We investigated mandibular dental arch form at the levels of both the clinically relevant application points of the orthodontic bracket and the underlying anatomic structure of the apical base. The correlation of both forms was evaluated and examined to determine whether the basal arch could be used to derive a standardized clinical arch form.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
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Tweed merrifield philosophy /certified fixed orthodontic courses by Indian ...Indian dental academy
The Indian Dental Academy is the Leader in
continuing dental education , training dentists
in all aspects of dentistry and offering a wide
range of dental certified courses in different
formats.
Indian dental academy provides dental crown &
Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit
www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Finishing and detailing /certified fixed orthodontic courses by Indian dental...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Tweed merrifield philosophy /certified fixed orthodontic courses by Indian ...Indian dental academy
The Indian Dental Academy is the Leader in
continuing dental education , training dentists
in all aspects of dentistry and offering a wide
range of dental certified courses in different
formats.
Indian dental academy provides dental crown &
Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit
www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Finishing and detailing /certified fixed orthodontic courses by Indian dental...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Straight wire – history, evolution and concepts /certified fixed orthodontic ...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Functional & ceph analysis for functional appliance /certified fixed ortho...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
00919248678078
Torque /certified fixed orthodontic courses by Indian dental academy Indian dental academy
The Indian Dental Academy is the Leader in
continuing dental education , training dentists
in all aspects of dentistry and offering a wide
range of dental certified courses in different
formats.
Indian dental academy provides dental crown &
Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit
www.indiandentalacademy.com ,or call
0091-9248678078
Mc namara analysis /certified fixed orthodontic courses by Indian dental acad...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all
aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
K- Sir loop /certified fixed orthodontic courses by Indian dental academy Indian dental academy
Welcome to Indian Dental Academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy has a unique training program & curriculum that provides students with exceptional clinical skills and enabling them to return to their office with high level confidence and start treating patients
State of the art comprehensive training-Faculty of world wide repute &Very affordable.
Malposition of unerupted mandibular second premolar in children with palatall...EdwardHAngle
Objective: To test the hypotheses that (1) the distal angulation of unerupted mandibular premolar
(MnP2) is significantly greater in children with palatally displaced canines (PDC) than in those in
a control sample; and (2) delayed tooth formation is significantly more frequent in children with
both malposed MnP2 and PDC than in children with PDC only.
Materials and Methods: We examined retrospectively panoramic radiographs from 43 patients
with PDC who had no previous orthodontics. A control sample consisted of age- and sex-matched
patients. The distal angle formed between the long axis of MnP2 and the tangent to the inferior
border was measured. Dental age was evaluated using the Koch classification.
Results: A significant difference was observed between the mean inclination of the right side
MnP2 in the PDC group (75.4 degrees) and that of the control group (85.8 degrees). This difference
was highly statistically significant (P < .0001). The same evaluation was carried out for the
left side, with similar results. The average dental age was found to be delayed in patients who
showed both abnormalities (malposed MnP2 and PDC) compared with patients who showed the
PDC anomaly only.
Conclusion: Both hypotheses are retained. Statistically, PDC and MnP2 malposition are significantly
associated suggesting a common genetic etiology, despite taking place on opposite jaws.
While the presence of PDC or MnP2 anomaly has been associated with a delay in tooth formation,
we find the presence of both anomalies to show a more profound delay. Our findings suggest a
delay in tooth formation as a possible common genetic mechanism for these 2 malposition anomalies.
Role of polycystin 1 in bone remodeling- orthodontic tooth movement study in ...EdwardHAngle
Objective: To test the hypothesis that polycystin-1 (PC1) is involved in orthodontic tooth movement as a mechanical sensor.
Materials and Methods: The response to force application was compared between three mutant and four wild-type 7-week-old mice. The mutant mice were PC1/Wnt1-cre, lacking PC1 in the craniofacial region. An orthodontic closed coil spring was bonded between the incisor and the left first molar, applying 20 g of force for 4 days. Micro–computed tomography, hematoxylin and eosin staining, and tartrate-resistent acid phosphatase (TRAP) staining were used to study the differences in tooth movement among the groups.
Results: In the wild-type mice the bonded molar moved mesially, and the periodontal ligament (PDL) was compressed in the compression side. The compression side showed a hyalinized zone, and osteoclasts were identified there using TRAP staining. In the mutant mice, the molar did not move, the incisor tipped palatally, and there was slight widening of the PDL in the tension area. Osteoclasts were not seen on the bone surface or on the compression side. Osteoclasts were only observed on the other side of the bone—in the bone marrow.
Conclusions: These results suggest a difference in tooth movement and osteoclast activity between PC1 mutant mice and wild-type mice in response to orthodontic force. The impaired tooth movement and the lack of osteoclasts on the bone surface in the mutant working side may be related to lack of signal from the PDL due to PC1 deficiency.
Straight wire – history, evolution and concepts /certified fixed orthodontic ...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Functional & ceph analysis for functional appliance /certified fixed ortho...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
00919248678078
Torque /certified fixed orthodontic courses by Indian dental academy Indian dental academy
The Indian Dental Academy is the Leader in
continuing dental education , training dentists
in all aspects of dentistry and offering a wide
range of dental certified courses in different
formats.
Indian dental academy provides dental crown &
Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit
www.indiandentalacademy.com ,or call
0091-9248678078
Mc namara analysis /certified fixed orthodontic courses by Indian dental acad...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all
aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
K- Sir loop /certified fixed orthodontic courses by Indian dental academy Indian dental academy
Welcome to Indian Dental Academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy has a unique training program & curriculum that provides students with exceptional clinical skills and enabling them to return to their office with high level confidence and start treating patients
State of the art comprehensive training-Faculty of world wide repute &Very affordable.
Malposition of unerupted mandibular second premolar in children with palatall...EdwardHAngle
Objective: To test the hypotheses that (1) the distal angulation of unerupted mandibular premolar
(MnP2) is significantly greater in children with palatally displaced canines (PDC) than in those in
a control sample; and (2) delayed tooth formation is significantly more frequent in children with
both malposed MnP2 and PDC than in children with PDC only.
Materials and Methods: We examined retrospectively panoramic radiographs from 43 patients
with PDC who had no previous orthodontics. A control sample consisted of age- and sex-matched
patients. The distal angle formed between the long axis of MnP2 and the tangent to the inferior
border was measured. Dental age was evaluated using the Koch classification.
Results: A significant difference was observed between the mean inclination of the right side
MnP2 in the PDC group (75.4 degrees) and that of the control group (85.8 degrees). This difference
was highly statistically significant (P < .0001). The same evaluation was carried out for the
left side, with similar results. The average dental age was found to be delayed in patients who
showed both abnormalities (malposed MnP2 and PDC) compared with patients who showed the
PDC anomaly only.
Conclusion: Both hypotheses are retained. Statistically, PDC and MnP2 malposition are significantly
associated suggesting a common genetic etiology, despite taking place on opposite jaws.
While the presence of PDC or MnP2 anomaly has been associated with a delay in tooth formation,
we find the presence of both anomalies to show a more profound delay. Our findings suggest a
delay in tooth formation as a possible common genetic mechanism for these 2 malposition anomalies.
Role of polycystin 1 in bone remodeling- orthodontic tooth movement study in ...EdwardHAngle
Objective: To test the hypothesis that polycystin-1 (PC1) is involved in orthodontic tooth movement as a mechanical sensor.
Materials and Methods: The response to force application was compared between three mutant and four wild-type 7-week-old mice. The mutant mice were PC1/Wnt1-cre, lacking PC1 in the craniofacial region. An orthodontic closed coil spring was bonded between the incisor and the left first molar, applying 20 g of force for 4 days. Micro–computed tomography, hematoxylin and eosin staining, and tartrate-resistent acid phosphatase (TRAP) staining were used to study the differences in tooth movement among the groups.
Results: In the wild-type mice the bonded molar moved mesially, and the periodontal ligament (PDL) was compressed in the compression side. The compression side showed a hyalinized zone, and osteoclasts were identified there using TRAP staining. In the mutant mice, the molar did not move, the incisor tipped palatally, and there was slight widening of the PDL in the tension area. Osteoclasts were not seen on the bone surface or on the compression side. Osteoclasts were only observed on the other side of the bone—in the bone marrow.
Conclusions: These results suggest a difference in tooth movement and osteoclast activity between PC1 mutant mice and wild-type mice in response to orthodontic force. The impaired tooth movement and the lack of osteoclasts on the bone surface in the mutant working side may be related to lack of signal from the PDL due to PC1 deficiency.
Purpose: To assess the amount of dental and skeletal expansion and stability after surgically assisted
rapid maxillary expansion (SARPE).
Patients and Methods: Data from 20 patients enrolled in this prospective study were collected before
treatment, at maximum expansion, at the removal of the expander 6 months later, before any second
surgical phase, and at the end of orthodontic treatment, using posteroanterior cephalograms and dental
casts.
Results: With SARPE, the mean maximum expansion at the first molar was 7.48 1.39 mm, and the
mean relapse during postsurgical orthodontics was 2.22 1.39 mm (30%). At maximum, a 3.49 1.37
mm skeletal expansion was obtained, and this expansion was stable, such that the average net expansion
was 67% skeletal.
Conclusion: Clinicians should anticipate a loss of about one third of the transverse dental expansion
obtained with SARPE, although the skeletal expansion is quite stable. The amount of postsurgical relapse
with SARPE appears quite similar to the changes in dental-arch dimensions after nonsurgical rapid palatal
expansion, and also quite similar to dental-arch changes after segmental maxillary osteotomy for
expansion.
Angular changes and their rates in concurrence to developmental stages of the...EdwardHAngle
In the early developmental stage of the mandibular second premolar (MnP2), it is not unusual to find the tooth extremely angulated to the lower border of the mandible, as seen in the panoramic roentgenogram. On eruption, the tooth, in most cases, is close to being upright. However, impaction or other types of malocclusions due to its ectopic eruption are not rare.
Malposition of unerupted mandibular second premolar in children with cleft li...EdwardHAngle
Objective: To determine whether distoangular malposition of the unerupted mandibular second
premolar (MnP2) is more frequent in children with unilateral clefts of the lip and palate.
Materials and Methods: This retrospective study examined panoramic radiographs from 45 patients
with unilateral clefts of the lip and/or palate who had no previous orthodontics. A control
sample consisted of age- and sex-matched patients. The distal angle formed between the long
axis of MnP2 and the tangent to the inferior border was measured. The mean, standard deviation,
and range were calculated for the angles measured in the cleft and the control groups. The
significance of the differences between the means was evaluated by the paired t-test. The angles
of the cleft and noncleft sides were also measured and compared.
Results: The mean inclination of the MnP2 on the cleft side was 73.6°, compared with 84.6° in
the control group. This difference was highly significant statistically (P < .0001). The difference
in angles from the cleft and noncleft sides was 0.7°, not statistically significant. A significant association
was found between clefting and distoangular malposition of the developing MnP2, suggesting
a shared genetic etiology. This association is independent of the clefting side, ruling out
possible local mechanical effects.
Conclusion: Clinicians should be aware of the potential for anomalous development of MnP2 in
children with clefts.
Transverse growth of the maxilla and mandible in untreated girls with low, av...EdwardHAngle
The purpose of this study was to investigate maxillary and mandibular transverse growth in
untreated female subjects with low, average, and high mandibular plane angles longitudinally from ages 6 to 18.
Increased occurrence of dental anomalies associated with infraocclusion of de...EdwardHAngle
Objective: To test the null hypothesis that there is no relationship between infraocclusion and the
occurrence of other dental anomalies in subjects selected for clear-cut infraocclusion of one or
more deciduous molars.
Materials and Methods: The experimental sample consisted of 99 orthodontic patients (43 from
Boston, Mass, United States; 56 from Jerusalem, Israel) with at least one deciduous molar in
infraocclusion greater than 1 mm vertical discrepancy, measured from the mesial marginal ridge of
the first permanent molar. Panoramic radiographs and dental casts were used to determine the
presence of other dental anomalies, including agenesis of permanent teeth, microdontia of
maxillary lateral incisors, palatally displaced canines (PDC), and distal angulation of the mandibular
second premolars (MnP2-DA). Comparative prevalence reference values were utilized and
statistical testing was performed using the chi-square test (P< .05) and odds ratio.
Results: The studied dental anomalies showed two to seven times greater prevalence in the
infraocclusion samples, compared with reported prevalence in reference samples. In most cases,
the infraoccluded deciduous molar exfoliated eventually and the underlying premolar erupted
spontaneously. In some severe phenotypes (10%), the infraoccluded deciduous molar was
extracted and space was regained to allow uncomplicated eruption of the associated premolar.
Conclusion: Statistically significant associations were observed between the presence of
infraocclusion and the occurrence of tooth agenesis, microdontia of maxillary lateral incisors,
PDC, and MnP2-DA. These associations support a hypothesis favoring shared causal genetic
factors. Clinically, infraocclusion may be considered an early marker for the development of later
appearing dental anomalies, such as tooth agenesis and PDC.
Craniofacial growth in untreated skeletal class i subjects with low, average,...EdwardHAngle
The dental measurements showed few changes with growth in all groups. In terms of skeletal measurements from ages 9 to 18, similar growth changes were found between the sexes in most angular measurements, but males had larger values in linear measurements than females.
Short term and long-term stability of surgically assisted rapid palatal expan...Dr Sylvain Chamberland
Introduction: The purpose of this article is to present further longitudinal data for short-term and long-term
stability, following up our previous article in the surgery literature with a larger sample and 2 years of stability
data. Methods: Data from 38 patients enrolled in this prospective study were collected before treatment, at maximum
expansion, at removal of the expander 6 months later, before any second surgical phase, at the end of
orthodontic treatment, and at the 2-year follow-up, by using posteroanterior cephalograms and dental casts.
Results: With surgically assisted rapid palatal expansion (SARPE), the mean maximum expansion at the first
molar was 7.60 6 1.57 mm, and the mean relapse was 1.83 6 1.83 mm (24%). Modest relapse after completion
of treatment was not statistically significant for all teeth except for the maxillary first molar (0.99 6 1.1 mm). A
significant relationship (P-.0001) was observed between the amount of relapse after SARPE and the posttreatment
observation. At maximum, a skeletal expansion of 3.58 6 1.63 mm was obtained, and this was stable.
Conclusions: Skeletal changes with SARPE were modest but stable. Relapse in dental expansion was almost
totally attributed to lingual movement of the posterior teeth; 64% of the patients had more than 2 mm of dental
changes. Phase 2 surgery did not affect dental relapse.
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Effects of bonded rapid palatal expansion on the transverse dimensions of the...EdwardHAngle
The purpose of this study was to examine the maxillary response on the transverse dimensions to rapid palatal expansion (RPE) by using cone-beam computed tomography (CBCT).
Long term clinical and bacterial effetcx of xylitol on paitnets with fixed or...EdwardHAngle
Background: The objective of this study was to evaluate long-term clinical and bacterial effects of using 6 g of
xylitol per day for 3 months on patients with full fixed orthodontic appliances.
Methods: The study was a pilot clinical trial that included 41 subjects who were undergoing orthodontic
treatment. The subjects were randomly divided into three groups. Group A received xylitol chewing gum, group B
received xylitol dissolvable chewable tablets, and Group C served as the control group and did not receive xylitol
gums or tablets. Clinical examination and the collection of plaque and saliva samples were carried out at baseline
and 3, 6, and 12 months. All three groups were given oral hygiene instruction and were put on a 6-month cleaning
and topical fluoride schedule. Plaque scores and bacterial counts were used to evaluate the effectiveness of the
different approaches at reducing the caries risk.
Results: Xylitol groups did not experience any more reduction in plaque score, plaque MS counts, or salivary MS
counts than the control group nor did they have lower values at any of the time points. Chewing gum did not
significantly increase the incidence of debonded brackets over the other groups.
Conclusions: Xylitol does not have a clinical or bacterial benefit in patients with fixed orthodontic appliances. Oral
hygiene instructions and 6-month topical fluoride application were effective at reducing plaque scores and bacterial
counts in patients with full fixed appliances regardless of whether or not xylitol was used.
Influence of common fixed retainers on the diagnostic quality of cranial magn...EdwardHAngle
Introduction: Orthodontists are often asked to remove fixed retainers before magnetic resonance imaging
(MRI). This study was undertaken to assess the effects of 2 commonly used fixed retainers on MRI distortion
and whether they should be removed. Methods: MRI scans were performed on a dry skull with Twistflex (Dentaurum,
Ispringen, Germany) and Ortho Flex Tech (Reliance Orthodontic Products, Itasca, Ill) retainers. Two
neuroradiologists independently ranked the distortions. The influence of the fixed retainers' alloys, their distance
to the area of diagnosis, location, strength of the magnetic field, and the spin-echo sequence were examined.
Statistical analysis included kappa and Pearson chi-square tests. Results: Ortho Flex Tech retainers caused
no distortion. Twistflex retainers caused distortion in 46% of the tests in areas close to the retainer (tongue
and jaws). Maxillary fixed retainers and the combination of maxillary and mandibular fixed retainers further
increased the distortion. Greater distortion was observed with 3-T magnetic fields and T1-weighted spin-echo
sequences. Conclusions: Removal of the Ortho Flex Tech retainer is unnecessary before MRI. Removal of
the Twistflex should be considered if the MRI scans are performed to diagnose areas close to the fixed retainers,
when 3-T magnetic fields and T1-weighted sequences are used, and when both maxillary and mandibular fixed
retainers are present.
Effects of rapid palatal expansion on the sagittal and vertical dimensions of...EdwardHAngle
The purpose of this study was to use cone-beam computed tomography imaging to examine the skeletal and dental changes in the sagittal and vertical dimensions after rapid palatal expansion.
Subjective classification and objective analysis of the mandibular dental arc...EdwardHAngle
Our objective was to evaluate the relationship between subjective classification of dental-arch shape, objective analyses via arch-width measurements, and the fitting with the fourth-order polynomial equation.
Two Treatment Approaches for Missing Maxillary Lateral Incisors: A CaseAbu-Hussein Muhamad
Missing maxillary lateral incisors create an esthetic problem with specific orthodontic and prosthetic considerations. The aim of the present study is to evaluate the clinical success of the transmucosal flapless implant placement and immediate loading of the implants to restore the agenic lateral incisors after completing the orthodontic treatment and during the retention period.
Journal Club Presentation on Overlay Removable Partial DentureNeerajaMenon4
Overlay removable partial dentures (ORPDs), a subset of overdentures, are often referred to as an RPD that has part of their components covering the occlusal surface of the abutment teeth to restore them into a functional occlusion
dentists, orthodontists and other experts in the past. While prevention and cure of dental diseases, surgical reconstitution to address teeth anomalies and research studies on teeth and development of the dental arch during the growing up years has been the main concerns across the past decades, in recent years, substantial effort has been evident in the field of mathematical analysis of the dental arch curve, particularly of children from varied age groups and diverse ethnic and national origins. The proper care and development of the primary dentition into permanent dentition is of major importance and the dental arch curvature, whose study has been related intimately by a growing number of dentists and orthodontists to the prospective achievement of ideal occlusion and normal permanent dentition, has eluded a proper definition of form and shape. Many eminent authors have put forth mathematical models to describe the teeth arch curve in humans. Some have imagined it as a parabola, ellipse or conic while others have viewed the same as a cubic spline. Still others have viewed the beta function as best describing the actual shape of the dental arch curve. Both finite mathematical functions as also polynomials ranging from 2nd order to 6th order have been cited as appropriate definitions of the arch in various studies by eminent authors. Each such model had advantages and disadvantages, but none could exactly define the shape of the human dental arch curvature and factor in its features like shape, spacing and symmetry/asymmetry. Recent advances in imaging techniques and computer-aided simulation have added to the attempts to determine dental arch form in children in normal occlusion. This paper presents key analysis models & compares them through some secondary research study.
Keywords
Dental Arch, Curve,Normal Occlussion
9.Umrani S, Mathew P, Hemant AV, Tiwari R, Dixit H. A review on Extraction versus Non-extraction on Facial and Smile Esthetics. Int J Oral Health Med Res 2017;4(3):83-86.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
2. during the 1930s. He established his diagnostic analysis in
favor of extraction and refined the mechanics for extrac-
tion treatment. Simultaneously, another Angle student,
Begg,10
also changed to the extraction technique and
sought anthropologic evidence for extraction treatment
because of less mastication required in modern diets.
Since then, this theory was confirmed by case reports, and
most orthodontists are now convinced of the validity of
this theory.11,12
However, an objective limit for buccal or
labial tooth movement in any patient, especially those
with mild crowding, is still not available today.2
As the frequency of extraction orthodontic treatment
has decreased over the last 30 years, a new bone-growing
theory has emerged. Esthetic preference for fuller profiles,
temporomandibular disorder problems,2
and the emer-
gence of functional appliance therapy13
were contributing
factors, but, most significantly, it was found that extrac-
tion did not insure stability.14
With stability not guaran-
teed, extraction treatment lost much of its perceived
advantage. Recently, the clinical results of a new orth-
odontic appliance were reported.15
Its developer claimed
that buccal tooth movements without tipping could be
achieved with his biocompatible appliance with extremely
light forces. Computed tomography images of expanded
teeth from severely crowded dental arches were shown,
and apparently healthy alveolar bone was demonstrated as
evidence for this bone-growing theory. Most clinicians,
however, still explain to their patients that there might be
a limit for expansion of the dental arch with any appliance.
Furthermore, we still do not know exactly the limit for
each patient.
The purpose of this study was to investigate the
relationship between the dental arch form and the
supporting bone. We hypothesized that there is a
quantifiable relationship between basal and dental arch
forms, and that basal-bone landmarks can be used as
reliable references for determining biologic arch form
in clinical orthodontics.
MATERIAL AND METHODS
The mandibular dental casts of 35 patients (13
male, 22 female) were randomly selected from a
sample of 750. The mandible was studied because
therapeutic possibilities are more limited than in the
maxilla, and the maxillary arch form is strongly asso-
ciated with the mandibular form.2,16
The subjects’
pretreatment casts were identified as skeletal Class I
(ANB angle, 0°-4°) and dental Class I (canine and
molar relationship according to Angle classification)
with fully developed permanent dentitions from first
molar to first molar. The second molars were excluded
from analysis because the age of most patients pre-
cluded ascertainment of complete eruption of this tooth.
The patients had only minimal restorations with no
prosthetic crowns and were excluded if they had
occlusal wear or gingival defects, or if the mucogingi-
val junction was not identifiable on the model. Mild
crowding or spacing (Ͻ2 mm) was acceptable, but no
subjects requiring extractions for arch-length defi-
ciency were included in the sample. The average age of
these patients was 17 years 11 months.
The dental casts were laser scanned with a computer-
assisted noncontact high-definition 3-dimensional (3D)
scanning system. This system consisted of a laser-
scanning unit (Dental Plaster Model Shape Scanning
System,17
Surflacer model VMS-100F, UNISN, Osaka,
Japan), a computer-aided-design software program
(Dent-Merge, version 5.0; UNISN), and dental cast
analyzing software (Surfacer, version 9.0, Imageware,
Ann Arbor, Mich). This setup was used for image
production and refinement, and landmark identification.
A detailed description of the performance characteris-
tics, including measurement accuracy of this data-
recording system, was reported elsewhere.18
The mea-
suring device of the laser-scanning unit consisted of a
slit-ray laser projector and 2 sets of charged-coupled
device video cameras to capture the reflected images.
X, y, and z coordinate data and data to measure the
circumference of the object was produced as a result.
The scanner was connected to the computer for image
processing. The dental casts were projected and
scanned by a revolving polygon mirror with a slit-ray
laser beam of 670 nm wavelength at 3 mW output.
Triangulation was used to determine the location of
each point with a measurement error of less than 0.05
mm.The generation of 3D graphics of each dental cast
took approximately 80 minutes. About 90,000 sets of
coordinates (x, y, z) per model were stored in the
computer.
Each mandibular dental cast was scanned at 3
angles in the frontal and sagittal planes (Fig 1, a). The
image processor converted the raster coordinates and
brightness data of the analog video signals’ input from
the video cameras into digital data. The computer
imported the digital data and converted the picture
coordinates to 3D spatial coordinates. The data was
synthesized, manually corrected for scanning errors, and
merged into a single data set for each model with the
Dent-Merge software. With cast analyzing software, a 3D
model of the entire mandibular dentition and its adjacent
structures was constructed (Fig 1, b and c).
By using the cast analyzing software, 2 reference
points (1 on the crown, and 1 at the mucogingival
junction) were selected for each tooth from the right to the
left first molar for a total of 24 points for each model.
The FA point is defined as the midpoint of the facial
American Journal of Orthodontics and Dentofacial Orthopedics
Volume 134, Number 3
Ronay et al 431
3. axis of the clinical crown, which is the most prominent
part of the central lobe on each crown’s facial surface
except for the molars.19
For the first molars, the facial
axis of the clinical crown is represented by the mesio-
buccal groove that separates the 2 large facial cusps.
The WALA ridge is defined as the most prominent
point on the soft-tissue ridge immediately occlusal to the
mucogingival junction. It is located at or nearly at the
same vertical level as the horizontal center of rotation of
each tooth.20
WALA was measured directly below FA of
each tooth perpendicular to the occlusal plane. This point
varied in its occlusogingival position from tooth to tooth.
Both points were digitized as coordinates (x, y, z)
and exported in an ASCII format from the Surfacer
software into Excel 2002 software (Microsoft, Red-
mond, Wash). A standard graph format was created to
enable comparisons of the patients. The data was first
translated, shifting the midpoint between the WALA
and FA points of the central incisors to the origin of the
graph (x-y intersection). Then it was rotated, relocating
the midpoint of the first molars to the y-axis. The
positions of the rotated reference points and the curve
were confirmed on the graphic display of the software
program. This method was applied to the data of each
set of FA and WALA points, and average FA and
WALA curves were created (Fig 2).
Statistical analysis
Descriptive statistics including the average and
standard deviation of the relative distances between FA
and WALA points of corresponding teeth were com-
puted and shown graphically. The average values and
Fig 1. a, Original model scanning; b, polygon wire-frame image; c, Gouraud-shaded image.
Fig 2. Sample FA and WALA curves superimposed.
American Journal of Orthodontics and Dentofacial Orthopedics
September 2008
432 Ronay et al
4. standard deviations of the intercanine and intermolar
widths at FA and WALA including their ratios were
calculated. The Pearson correlation coefficients be-
tween the width at the bilateral FA points and the
WALA points at the canine and molar levels were
calculated and statistically analyzed at the 0.01 and
0.05 levels of significance. Furthermore, the Pearson
correlation coefficients between the ratios at the FA and
WALA point widths were calculated and also statisti-
cally analyzed at the 0.01 and 0.05 levels. These
evaluations were made to investigate the relationship
between points representing the dental arch and those
constituting the basal arch.
RESULTS
A data table was created for each patient (Fig 3).
All 3 coordinates (x, y, z) of the FA and the WALA
points were described for each tooth, starting at the
right first molar and ending with the left first molar. The
third dimension (z, vertical) was omitted in further
analysis to facilitate comparison in arch width and
length. To compare patients, the data was standardized
as described above. The patient tables also show the
absolute distance between FA and WALA of the
corresponding teeth in millimeters. The FA and WALA
curves were superimposed to evaluate their relationship
Fig 3. Digitized FA and WALA points were imported into Excel 2002 (Microsoft, Redmond, Wash).
First, the distances between the 12 pairs were digitally calculated to create the “original” data. Then
the data was “translated” with the midline at the origin of the x-y axis. Finally, the data was “rotated”
to relocate the first molars as bilateral reference points for standardized y-axis positioning that
would permit comparison between subjects. Canine and molar widths and depths, and canine to
molar ratios, were determined. This method was applied to each FA-WALA data set. FDI
tooth-numbering system; R, right; L, left.
American Journal of Orthodontics and Dentofacial Orthopedics
Volume 134, Number 3
Ronay et al 433
5. (Fig 2). Male and female data were combined because
initial analysis showed them to be indistinguishable.
The distribution of FA and WALA points on the
mandibular cast is shown in Figures 4 and 5, respec-
tively, with the FA and WALA curves produced
through connection of their single values by linear
interpolation. Those curves are individual and the
values describing the same teeth are scattered, espe-
cially in the premolar and molar areas.
The average relative distances between correspond-
ing FA and WALA points were created by summing the
values of the right and left sides. This data (Table I) is
shown in Figure 6, illustrating which FA points are
located more lingually (positive values) and which are
located more labially (negative values) in relation to
corresponding WALA points.
Table II gives the intercanine and intermolar widths
for the FA and WALA points in millimeters and the FA
Fig 4. FA curves created through linear interpolation of the individual FA values.
Fig 5. WALA curves created through linear interpolation of the individual WALA values.
American Journal of Orthodontics and Dentofacial Orthopedics
September 2008
434 Ronay et al
6. and WALA ratios of the canines and molars to each
other, including averages and standard deviations. In
the canine area, increasing distances between FA points
were accompanied by increasing distances between
WALA points. However, the corresponding increase in
distances between FA points was always larger. With a
canine correlation coefficient of 0.75, this data was
highly statistically significant (Table III). Similarly, in
the molar region where the proportional increase in
distances between the WALA points was even larger,
the correlation was also highly significant (0.87). A
comparison of the x- and y-coordinates shows that in
the canine area there was greater variation in FA than in
WALA distances. To a lesser degree, this tendency was
also observed in the molar region.
DISCUSSION
Retention is still a major issue in orthodontics.
Theories have been proposed to minimize posttreat-
ment relapse, such as creating a proper occlusion4
and
muscular balance,21
uprighting mandibular incisors,22
and maintaining the pretreatment apical base6
and
intercanine and intermolar widths.14
The purpose of our
analysis was to estimate arch dimensions that permit
stable treatment goals.2
Orthodontists generally accept
the importance of respecting basal bone when planning
treatment. Treatment decisions regarding arch form in
particular should be related to the patient’s underlying
basal anatomy.
The definition of apical base is not completely clear
in the literature. These words—apical base, basal bone,
basal arch, and supporting bone—are not anatomic
terminology and are used only in orthodontics. Defini-
tions of the vertical position of the basal area of the
alveolar process vary. For example, in 1925, Lund-
ström6
defined it as follows: “in normal cases the apical
base will in the horizontal plane coincide with the
region in which the apices of the roots are located.”
Howes23
stated that the basal arch refers to the apical
third of the alveolus and the bone that supports the
alveolar processes below the mandibular teeth. He also
explained that it is the most constricted area of the
alveolus and is generally about 8 mm below the
gingival margin.
Clinicians generally assess basal anatomy by either
subjective palpation or analyzing lateral cephalograms.
The latter uses Points A and B to define the anterior
limit of the apical bases, but it obviously does not take
into account actual width and overall size. With dental
casts, the method of recording the most concave con-
tour of the sulci in relation to the apices of the teeth has
been reported.24
Various studies have looked at the position of the
teeth in the basal bone, and several methods for
determining this relationship have been used. In 1945,
Tweed25
described a method of sectioning dental casts
in the midline to determine the relationship of the
incisors to the alveolar and basal bone. Sergl et al24
measured the maxillary and mandibular apical base
area using a gnathograph specially designed for this
purpose. Oda et al26
presented a technique to record and
evaluate mandibular apical base form and tooth posi-
tion with computed tomography scans.
The use of 3D scanning devices has been reported
recently.27
The area of interest is most likely between
the bottom of a periodontal pocket and the apex of a
tooth. A reason for this variation in definition is the
difficulty in estimating the height of the root apex of
tooth without x-ray evaluation. However, there is not
enough data about the limit of buccal or labial tooth
movements, and it is not clear how much the bones can
be changed. In 2000, Andrews and Andrews20
pro-
posed a new term, WALA ridge, to indicate a surface
structure at the same level as basal bone. The WALA
ridge is the ridge of tissue at the mucogingival junction,
and they suggested that the horizontal arch shape of this
ridge of an initial mandibular basal arch in an orthodon-
tic patient is similar to the archwire form of the dental
arch. The WALA ridge is easy to identify and might be
more clinically reliable than estimation of the root
apex. However, that hypothesis has not been widely
discussed and confirmed. This is the first report that
examines the usefulness of WALA points to represent
the basal arch and their relevance in determining dental
arch form, but further research is required.
The use of different points in different reports could
have caused confusion regarding arch form. Some
studies used the arch form based on points where the
orthodontic bracket is placed, and others used the arch
form connecting the incisal edges and cusp tips of the
teeth. Different results are obtained with these measure-
ment methods on the same dental cast.28
This is the first
study to investigate the mandibular dental arch form
while considering both the clinically relevant working
point of the orthodontic bracket and wire and the
underlying anatomic-biologic structure of the basal
bone to correlate these structures. Most other arch-form
Table I. Average distances (mm) of WALA points
relative to corresponding FA points and their standard
deviations (n ϭ 70) (FDI tooth-numbering system)
Tooth 1 2 3 4 5 6
Average Ϫ1.21 Ϫ0.88 Ϫ0.32 0.59 1.78 2.77
SD 1.24 1.07 1.63 1.28 1.10 0.89
American Journal of Orthodontics and Dentofacial Orthopedics
Volume 134, Number 3
Ronay et al 435
7. studies attempted to fit generalized mathematic or
geometric functions to the dentition but did not look for
an anatomic reference for deriving an “ideal” form for
each patient.
Arch form has been analyzed on plaster reproduc-
tions of the dentition for years. By using digital models
(3D virtual images), point identification takes on new
meaning, particularly for basal arch form. Each identi-
fied point has 3 known Cartesian coordinates that
permit precise analysis of its position. Relationships
between some points can be determined on digital
models regardless of interfering structures. Virtual
points within the model can also be created and
comparisons made between internal and external or
surface landmarks.
Relatively large individual variations of dental arch
form were found with both FA and WALA points as
shown in Figures 4 and 5, in spite of excluding dental
casts with significant crowding or irregularities. This
can be seen as a naturally occurring variation of tooth
position and bone anatomy in Class I occlusion. These
wide variations in dental and basal arches can be
explained by genetic background and environmental
factors influencing the patient’s growth and develop-
ment. These observations suggest that the quantified
arch forms are highly individual and should not be
viewed as variations of a general arch form as had been
done in the past.
On the other hand, a statistically significant positive
correlation was found between the dental and basal
arches in untreated patients. Comparisons of canine and
molar values in Tables II and III show a constant
relationship between dental and basal arch forms. A
statistically significant positive correlation of canine
and molar widths to corresponding FA and WALA
points was found. This suggests that the dental arch
form is affiliated with the basal arch form (defined by
the WALA points) in each patient, supporting the
above-mentioned apical base theory. If the dental arch
form is altered without considering the basal arch form,
it might result in unhealthy periodontal conditions or
unstable treatment results. Additionally, by determin-
ing WALA values, one can estimate their correspond-
ing FA values and then determine clinical arch form,
which can produce an archwire form. A statistically
significant positive correlation also was found for the
WALA and FA canine-to-molar width ratio. This rela-
tionship was observed for both dental arch size and
shape.
These findings have considerable relevance for
treatment outcomes. An implant study in the 1980s
reported significant lateral expansion of the maxillary
basal bone by a functional appliance.13
A recent article
reported thinned or dehisced buccal plates after maxil-
lary palatal expansion therapy with computed tomog-
raphy.29
Ultimately, the new bone-growing theory is
still at odds the apical base theory.15
The new bone-
growing theorists claim that crowded posterior teeth
can be moved laterally, and buccal bones can be
developed without tipping and bone loss with ex-
tremely light forces. However, most orthodontists be-
lieve that the dental arch cannot usually be expanded in
a short time without a heavier force, such as with
palatal expansion. Thus, a classic controversy in orth-
Fig 6. Average distances (mm) of WALA points relative to corresponding FA points and their
standard deviations (n ϭ 70).
American Journal of Orthodontics and Dentofacial Orthopedics
September 2008
436 Ronay et al
8. odontics has been reignited. Research on the morphol-
ogy of the supporting bone after conventional and
newly developed orthodontic mechanics and stability
of the treatment results is therefore critical, and the
WALA and FA points used in this study might be
useful references for this purpose.
Our results demonstrate the ability to look at the
apical base and predict a patient’s dental arch form. It
will be of future interest to study whether other ana-
tomic landmarks could serve as an even more accurate
representations of basal bone. Additionally, it should be
determined whether the buccolingual relationships be-
tween the FA and WALA points are related to archwire
torque. Further research should also include the third
dimension when assessing patient data to give clini-
cians more information about the curve of Spee. How-
ever, the vertical distribution of WALA points might
depend on not only tooth inclination but also periodon-
tal conditions, such as the attachment level or the root
length of the patient. We expect that the WALA-FA
relationships will be different in patients with Class II
and Class III dental and skeletal relationships, as well
as in adults relative to growing patients. These are the
subjects of continuing investigations.
This study shows that distal to the mandibular
canines, the average distance between FA and WALA
points describing the same tooth changes buccolin-
gually. In this posterior area, the FA points are more
lingually located than the WALA points. This fact
might be linked to the clinically observed gradient of
crown torque along the dental arch but also to the
differences in basal vs dental arch shape. Andrews and
Andrews20
obtained different results. They reported
only positive values between FA and WALA points and
projected that the points at the mucogingival junction
were always more buccally positioned than the most
prominent part of the tooth crown. The difference in
results can be explained by their method or sample
selection. Nonetheless, our findings support their hy-
pothesis that WALA points can be used to describe the
basal arch and to draw conclusions regarding the
dimensions of the dental arch form. Additionally,
individual variations of the distance between the
WALA and FA points for each tooth were observed.
This might reflect the buccolingual inclination of the
teeth.
As a result of our research, we cannot confirm past
research postulating the existence of an ideal arch form
template. On the contrary, this study suggests that all
basal and dental arches should be individually derived.
Furthermore, the basal arch, represented by WALA
points, can be used as a clinical guide in fabricating
Table III. Correlation coefficients between FA and
WALA points at 3-3 width, 6-6 width, and (3-3/6-6)
ratio
3-3
width
6-6
width
(3-3/6-6)
ratio (%)
Correlation coefficient 0.750 0.869 0.750
t value (degree of freedom n-2 ϭ 33) 6.520 10.105 6.516
5% significance level 1.69 1.69 1.69
1% significance level 2.45 2.45 2.45
3-3, Canine to canine; 6-6, first molar to first molar.
Table II. FA and WALA point distances between ca-
nines and molars and their ratios
Patient
Distances (mm)
Ratios (%)
FA points WALA points
FA
ratio
(3-3/6-6)
WALA
ratio
(3-3/6-6)
3-3
width
6-6
width
3-3
width
6-6
width
1 28.00 54.50 29.27 60.27 51.37 48.57
2 27.05 50.26 26.50 54.54 53.81 48.59
3 29.80 52.50 28.50 57.76 56.77 49.33
4 28.29 55.28 30.85 59.25 51.17 52.07
5 26.81 48.34 29.37 56.10 55.45 52.34
6 28.26 53.35 30.82 58.15 52.97 53.00
7 30.01 48.77 31.50 54.75 61.53 57.53
8 27.07 52.29 28.01 55.78 51.77 50.23
9 26.00 50.29 28.26 56.33 51.70 50.17
10 26.50 50.75 28.00 53.78 52.21 52.05
11 28.95 56.48 29.42 57.58 51.25 51.10
12 27.02 53.11 27.01 59.26 50.86 45.57
13 26.05 50.10 28.29 56.78 52.00 49.82
14 26.36 48.93 26.53 53.41 53.87 49.67
15 26.05 53.14 24.34 57.35 49.02 42.45
16 28.53 51.59 30.76 59.55 55.31 51.65
17 28.00 48.75 30.75 53.25 57.43 57.76
18 29.54 51.05 30.04 54.06 57.87 55.58
19 24.27 45.50 23.75 49.75 53.35 47.73
20 30.25 59.30 29.75 66.51 51.02 44.73
21 26.50 49.00 27.75 53.75 54.08 51.62
22 29.50 50.74 31.75 57.00 58.12 55.71
23 25.76 47.83 27.81 52.80 53.87 52.68
24 23.52 51.00 24.50 55.50 46.11 44.14
25 27.54 50.01 27.00 52.76 55.06 51.17
26 27.01 49.77 30.00 55.01 54.26 54.53
27 25.67 46.34 27.25 53.05 55.40 51.37
28 28.75 50.50 31.01 58.50 56.92 53.01
29 29.95 54.35 30.29 60.59 55.11 49.99
30 27.00 50.99 30.50 54.75 52.94 55.71
31 27.50 53.00 29.75 58.75 51.88 50.63
32 27.25 54.00 29.99 59.77 50.46 50.18
33 27.07 46.40 29.55 52.81 58.35 55.96
34 29.26 49.31 29.51 55.79 59.34 52.90
35 27.77 50.33 30.04 56.30 55.17 53.36
Average 27.51 51.08 28.81 56.32 53.94 51.22
SD 1.60 2.92 2.02 3.14 0.03 0.04
3-3, Canine to canine; 6-6, first molar to first molar.
American Journal of Orthodontics and Dentofacial Orthopedics
Volume 134, Number 3
Ronay et al 437
9. individualized archwire templates. Consideration of the
anatomy of each mandibular base also ensures that
optimal function of the occlusion, periodontal health,
desired esthetic appearance, and, of course, stability of
the dental arch form can be achieved. With increasing
access to 3D patient data, this important information
will be available to practitioners and must be consid-
ered in orthodontic treatment planning and archwire
design.
CONCLUSIONS
1. Arch forms derived from both FA and WALA are
individual and cannot be defined by 1 generalized
shape. These results show that form, degree of
curvature, and other parameters of the alveolar
ridge and dental arch are subject to much variation.
2. WALA points can be useful in the predetermination
of a dental arch form. The highly significant corre-
lation of WALA and FA point width in the canine
and molar areas proves that assessments of WALA
points enable prediction of corresponding FA val-
ues and the clinical arch form.
We thank Mutsuji Muramoto, UNISN, Osaka, Ja-
pan, for generously providing the VMS Dental Plaster
Model Shape Scanning System for this study.
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