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.
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.
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.
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.
Mandibular arch form the relationship between dental and basal anatomyEdwardHAngle
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.
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.
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.
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.
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.
Mandibular arch form the relationship between dental and basal anatomyEdwardHAngle
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.
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.
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).
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.
Gingival recession—can orthodontics be a cure? evidence from a case presentationEdwardHAngle
Does orthodontic treatment help or hinder a patient’s periodontal status? What factors affect the
periodontium? Can those factors be managed in a way that remedies existing periodontal issues?
A 35-year-old woman presented with severe gingival recession and a unilateral Class II
malocclusion. The treatment plan was to correct the malocclusion in a way that torques the roots
more onto bone and to change her dental hygiene methods. With an extensive review of the
literature, this case review attempts to make sense of the enigma of gingival recession and
demonstrates an excellent treatment solution to concomitant orthodontic and periodontal
problems.
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.
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.
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.
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.
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.
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.
ABSTRACT
Objective: To evaluate the role of age as a moderator of bone regeneration patterns and
symphysis remodeling after genioplasty.
Method: Fifty-four patients who underwent genioplasty at the end of their orthodontic treatment
were divided into three age groups: younger than 15 years at the time of surgery (group 1), 15 to
19 years (group 2), and 20 years or older (group 3). Twenty-three patients who did not accept
genioplasty and had a follow-up radiograph 2 years after the end of their orthodontic treatment
were used as a control group. Patients were evaluated at three time points: immediate preoperative
(T1), immediate postoperative (T2,) and 2 years postsurgery (T3).
Results: The mean genial advancement at surgery was similar for the three age groups, but the
extent of remodeling around the repositioned chin was greater in group 1, less in group 2, and still
less in group 3. Symphysis thickness increased significantly during the 2-year postsurgery interval
for the three groups, and this increase was significantly greater in group 1 than in group 3.
Remodeling above and behind the repositioned chin also was greater in the younger patients. This
was related to greater vertical growth of the dentoalveolar process in the younger patients. There
was no evidence of a deleterious effect on mandibular growth.
Conclusion: The outcomes of forward-upward genioplasty include increased symphysis
thickness, bone apposition above B point, and remodeling at the inferior border. When indications
for this type of genioplasty are recognized, early surgical correction (before age 15) produces a
better outcome in terms of bone remodeling. (Angle Orthod. 0000;00:000–000.)
Evaluation of Hard and Soft Tissue Dimensions Around Zirconium Oxide Implant–...Dr Ripunjay Tripathi
journal club Evaluation of Hard and Soft Tissue Dimensions Around Zirconium Oxide Implant–Supported Crowns: A 1-Year Retrospective Study
Kniha at el , J Periodontol 2016;87:511-518.
Dental Patterns in Peruvians: A Panoramic Radiography StudyIván E Pérez
The dental pattern is defined as the combination of distinct codes assigned to describe specific tooth conditions including virgin, missing, and restored teeth that comprise the complete dentition or from discrete groups of teeth. This pattern can be then compared to the dentition of individual/s in an attempt to determine positive identification. The aims of the present investigation were to study and determine the diversity of dental patterns in Peruvian citizens based on a sample of panoramic radiographs. Digital panoramic radiographs of 900 adult Peruvian patients (450 female and 450 male) were evaluated to determine the dental patterns. The most frequent dental patterns found in the complete dentition, maxillae, upper-anterior and lower-anterior sextants were all-virgin-teeth (0.3%), all-extracted teeth (1.9%), all-virgin teeth (1%) and all-virgin-teeth (34.2% and 72.3%) respectively. The diversity was calculated by the use of the Simpson´s diversity index, the resulting values for the full-dentition, maxilla and mandible were over the 99.8% value and were similar to those previously reported in the scientific literature. This study demonstrates the positive benefit of dental patterns in the process of identification. Additionally a combination of codes is proposed that could prove useful in cases where a better radiographic description is required.
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).
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.
Gingival recession—can orthodontics be a cure? evidence from a case presentationEdwardHAngle
Does orthodontic treatment help or hinder a patient’s periodontal status? What factors affect the
periodontium? Can those factors be managed in a way that remedies existing periodontal issues?
A 35-year-old woman presented with severe gingival recession and a unilateral Class II
malocclusion. The treatment plan was to correct the malocclusion in a way that torques the roots
more onto bone and to change her dental hygiene methods. With an extensive review of the
literature, this case review attempts to make sense of the enigma of gingival recession and
demonstrates an excellent treatment solution to concomitant orthodontic and periodontal
problems.
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.
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.
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.
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.
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.
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.
ABSTRACT
Objective: To evaluate the role of age as a moderator of bone regeneration patterns and
symphysis remodeling after genioplasty.
Method: Fifty-four patients who underwent genioplasty at the end of their orthodontic treatment
were divided into three age groups: younger than 15 years at the time of surgery (group 1), 15 to
19 years (group 2), and 20 years or older (group 3). Twenty-three patients who did not accept
genioplasty and had a follow-up radiograph 2 years after the end of their orthodontic treatment
were used as a control group. Patients were evaluated at three time points: immediate preoperative
(T1), immediate postoperative (T2,) and 2 years postsurgery (T3).
Results: The mean genial advancement at surgery was similar for the three age groups, but the
extent of remodeling around the repositioned chin was greater in group 1, less in group 2, and still
less in group 3. Symphysis thickness increased significantly during the 2-year postsurgery interval
for the three groups, and this increase was significantly greater in group 1 than in group 3.
Remodeling above and behind the repositioned chin also was greater in the younger patients. This
was related to greater vertical growth of the dentoalveolar process in the younger patients. There
was no evidence of a deleterious effect on mandibular growth.
Conclusion: The outcomes of forward-upward genioplasty include increased symphysis
thickness, bone apposition above B point, and remodeling at the inferior border. When indications
for this type of genioplasty are recognized, early surgical correction (before age 15) produces a
better outcome in terms of bone remodeling. (Angle Orthod. 0000;00:000–000.)
Evaluation of Hard and Soft Tissue Dimensions Around Zirconium Oxide Implant–...Dr Ripunjay Tripathi
journal club Evaluation of Hard and Soft Tissue Dimensions Around Zirconium Oxide Implant–Supported Crowns: A 1-Year Retrospective Study
Kniha at el , J Periodontol 2016;87:511-518.
Dental Patterns in Peruvians: A Panoramic Radiography StudyIván E Pérez
The dental pattern is defined as the combination of distinct codes assigned to describe specific tooth conditions including virgin, missing, and restored teeth that comprise the complete dentition or from discrete groups of teeth. This pattern can be then compared to the dentition of individual/s in an attempt to determine positive identification. The aims of the present investigation were to study and determine the diversity of dental patterns in Peruvian citizens based on a sample of panoramic radiographs. Digital panoramic radiographs of 900 adult Peruvian patients (450 female and 450 male) were evaluated to determine the dental patterns. The most frequent dental patterns found in the complete dentition, maxillae, upper-anterior and lower-anterior sextants were all-virgin-teeth (0.3%), all-extracted teeth (1.9%), all-virgin teeth (1%) and all-virgin-teeth (34.2% and 72.3%) respectively. The diversity was calculated by the use of the Simpson´s diversity index, the resulting values for the full-dentition, maxilla and mandible were over the 99.8% value and were similar to those previously reported in the scientific literature. This study demonstrates the positive benefit of dental patterns in the process of identification. Additionally a combination of codes is proposed that could prove useful in cases where a better radiographic description is required.
transverse dentoskeletal features of anterior open bite in the mixed dentitio...Indian dental academy
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Aim: The present study was aimed at assessing the lingual concavities in the submandibular fossa region in patients requiring dental implants with the help of cone beam computed tomography (CBCT). Materials and methods: The present study included 140 patients who visited the department with the missing mandibular posterior teeth. CBCT images were obtained using planmeca machine. Cross sections of 1 mm of submandibular fossa in the region of 1st and 2nd molar were studied and Type I to III lingual concavities were analyzed by a radiologist. Results: Type I lingual concavity (< 2 mm) was seen in 23%, type II (2-3 mm) in 62% and Type III (> 3 mm) in 15% of patients. The difference was significant (p < 0.05). Males had slightly higher mean ± S.D value at 1st molar (2.6 mm ± 0.94) and 2nd molar (2.8 mm ± 0.90) on the left side and (2.7 mm ± 0.92) at 1st molar and (2.9 mm ± 0.93) at 2nd molar on the right side. The difference was nonsignificant (p > 0.05). Females had mean ± S.D value at 1st molar (2.3 mm ± 0.90) and (2.5 mm ± 0.92) at 2nd molar on the left side and (2.4 mm ± 0.91) at 1st molar and (2.8 mm ± 0.93) at 2nd molar. The difference was nonsignificant (p > 0.05. The difference between both genders was statistically nonsignifi-cant (p > 0.05). Conclusion: Type I bone is the best for placing an implant. The chances of complications are more in type II and III bone. CBCT provides necessary information before planning implant in the edentulous area. Clinical significance: Cone beam computed tomography (CBCT) is the best radiographic aid which is effective in delin-eating different types of bone in the mandibular posterior region.
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5. Describe the cough and sneeze reflexes
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Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
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Childhood and Athletic Beginnings
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Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
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Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
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Malposition of unerupted mandibular second premolar in children with palatally displaced canines
1. 796Angle Orthodontist, Vol 79, No 4, 2009 DOI: 10.2319/081808-435.1
Original Article
Malposition of Unerupted Mandibular Second Premolar in Children with
Palatally Displaced Canines
Miri Shalisha
; Stella Chaushua
; Atalia Wassersteinb
ABSTRACT
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 differ-
ence was highly statistically significant (P Ͻ .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 signifi-
cantly 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 anom-
alies. (Angle Orthod. 2009;79:796–799.)
KEY WORDS: Malposition; Dental anomalies; Mandibular second premolar; PDC, Genetic etiol-
ogy; Late development
INTRODUCTION
Orthodontists treat malposed teeth. As orthodon-
tists, we are interested in knowing what causes teeth
to assume abnormal positions during their develop-
ment. To gain this knowledge, we study malposition
anomalies. In a recent such study, it was discovered
that exaggerated distoangular malposition of the un-
erupted mandibular second premolar (MnP2) was as-
Department of Orthodontics, Hebrew University–Hadassah
School of Dental Medicine, Jerusalem, Israel.
Department of Orthodontics, School of Dental Medicine, Tel
Aviv University, Israel Defence Forces, Tel-Aviv, Israel.
Corresponding author: Dr Miri Shalish, Hebrew University–
Hadassah School of Dental Medicine, PO B 12272 Jerusalem,
Israel
(e-mail: mshalish@hadassah.org.il)
Accepted: October 2008. Submitted: August 2008.
ᮊ 2009 by The EH Angle Education and Research Foundation,
Inc.
sociated with agenesis of its antimere.1
This finding
relates the MnP2 malposition to a group of tooth de-
velopment abnormalities of possible common genetic
origin, including agenesis (hypodontia), peg-shaped
maxillary lateral incisors, small maxillary lateral inci-
sors, palatally displaced canines (PDC), infraocclusion
of primary molars, and transpositions of various
teeth.2–8
Accumulated evidence on associations
among this group go well beyond coincidence,8
sug-
gesting that they are part of a broader genetically re-
lated pattern of dental anomalies.
A genetic basis of PDC is widely acknowledged.4,9,10
Interestingly, delayed tooth formation was reported
both in children with PDC11,12
and in children with mal-
position of MnP2.13
This study was undertaken to test
the hypotheses that (1) the distal angulation of the
MnP2 is significantly greater in children with PDC than
in age- and sex-matched controls, and (2) delayed
tooth formation is a significantly more frequent finding
2. 797MALPOSITION OF MANDIBULAR SECOND PREMOLAR IN PDC
Angle Orthodontist, Vol 79, No 4, 2009
Figure 1. The distal angle between the long axis of the mandibular
second premolar and the tangent to the lower border of the mandible
defined on a typical drawing of the relevant part of an orthopanto-
mogram.
in children with both malposed MnP2 and PDC than
in children with PDC but with a normal inclination of
MnP2.
MATERIALS AND METHODS
Two samples, an experimental group and a control
group, were selected from the pretreatment records of
patients. The experimental sample consisted of 43 pa-
tients (15 males and 28 females). Age ranged from 8
to 14 years (mean, 11.5; standard deviation [SD], 1.4).
Criteria for inclusion in this sample included (1) unilat-
eral or bilateral PDC, (2) no previous orthodontic treat-
ment, (3) mandibular deciduous second molars pres-
ent, and (4) development of the MnP2 tooth bud in
stages D to G of tooth formation, according to the clas-
sification of Koch et al.14
Unerupted stage D is defined
with crown formation completed down to the cemento-
enamel junction, unerupted stage E is defined with
root length smaller than crown length, unerupted stage
F is defined with root length equal or larger than crown
length, and unerupted stage G is defined with walls of
the root canal parallel and the root apex still partially
open. Of 43 patients with PDC, 25 patients had bilat-
eral PDC, 10 had PDC on the right side only, and 8
had PDC on the left side only.
The control sample consisted of 43 patients with
normally erupting canines and was collected from the
same orthodontic patient pool to match age (rounded
to half year) and sex in the study group.
We developed a unique method by which to mea-
sure the inclination of the MnP2.1
In both samples,
panoramic radiographs were used to trace each
MnP2, along with the neighboring mandibular first mo-
lar, the deciduous second molar, and a tangent to the
inferior border of the mandibular body on that side.
The long axis of the MnP2 was determined as the line
connecting the uppermost point of the pulp with the
point bisecting the distance between the mesial and
distal points of the apex. A protractor was used to
measure the distal angle formed between the long axis
of the MnP2 and the line drawn tangent to the inferior
border of the mandible. Figure 1 shows a typical draw-
ing with assigned lines and the resulting angle. All
tracings were made independently by a single exam-
iner using 0.003 inch frosted acetate paper and a 0.5
mm pencil.
Descriptive statistics, including mean, standard de-
viation, and range, were calculated for the unerupted
MnP2 angles measured in the experimental and the
control groups. The significance of the differences be-
tween compared means was evaluated using the Stu-
dent t-test for paired samples. The significance level
was set at P Ͻ .05. Some patients had unerupted
MnP2 on both sides. However, because one may not
include more than 1 data point per patient in the same
statistics, the question of which side to choose arises,
as well as whether this arbitrary choice influences the
result and how. To avoid any possible inconsistency
while showing all the data, we collected 2 independent
sets of data: one for all the right sides of the sample
group, and another for the left sides of the same
group, each matched with the same side in the control
sample.
To quantify the error of the method, a second set of
data was traced and measured 1 month later by the
same examiner. Standard deviations calculated for 2
repeated measurements of 2 tracings of 6 different
panoramic roentgenograms were used as intraexami-
ner error. This procedural error was found to be 1.0
degree, within reasonable limits in the context of this
study.
To test the second hypothesis, we had to define the
developmental stage of MnP2 and single out patients
with malposed MnP2. The developmental stage of
MnP2 was evaluated using the Koch classification.13
MnP2 malposition was defined as the distal angle (be-
tween the long axis of MnP2 and the tangent to the
3. 798 SHALISH, CHAUSHU, WASSERSTEIN
Angle Orthodontist, Vol 79, No 4, 2009
Table 1. Interpatient Test: Sample vs. Control—Right Sidea,b
Group N Range Mean SD t-Test Value P Value
Right side MnP2 in the experimental sample (PDC) 40 51.0–108.0 75.4 10.2 Ϫ5.53 Ͻ.0001
Right side MnP2 in the control sample (reference) 40 71.0–98.0 85.8 6.2
a
Comparison of distoangular malposition of the MnP2 (ie, distal angle formed at intersection of long axis of unerupted MnP2 and tangent
to inferior border of the mandible) in degrees, between the right side MnP2 in the PDC sample and that in the control sample.
b
MnP2 indicates unerupted mandibular second premolar tooth; PDC, palatally displaced canine.
Table 2. Interpatient Test: Sample vs. Control—Left Sidea,b
Group N Range Mean SD t-Test Value P Value
Left side MnP2 in the experimental sample (PDC) 37 61.0–97.0 77.9 8.5 Ϫ4.54 Ͻ.0001
Left side MnP2 in the control sample (reference) 37 76.0–97.0 85.1 4.5
a
Comparison of distoangular malposition of the MnP2 (ie, the distal angle formed at the intersection of the long axis of unerupted MnP2
and tangent to the inferior border of the mandible) in degrees, between the left-side MnP2 in the PDC sample and the control sample.
b
MnP2 indicates unerupted mandibular second premolar tooth; PDC, palatally displaced canine.
lower border of the mandible) when it was smaller than
75 degrees. This value is about the mean angle of
malposed MnP2, as observed in previous studies.1,15
RESULTS
Table 1 shows descriptive statistics of the right-side
MnP2 in the experimental group and the same side in
the age- and sex-matched paired control group. Of 43
patients with PDC, 40 had an unerupted MnP2 on the
right side. The mean distal inclination of the MnP2 in
the right side of the experimental sample was 75.4 de-
grees, compared with a mean of 85.8 degrees ob-
tained for the same side in the matched control group.
The mean increase of 10.4 degrees in the distoangular
malposition of the developing MnP2 in PDC patients
was highly statistically significant (P Ͻ .0001).
Table 2 shows the descriptive statistics of the left-
side MnP2 in the experimental group and the same
side in the age- and sex-matched paired control group.
Of 43 patients with PDC, 37 had an unerupted MnP2
on the left side. The mean distal inclination of the
MnP2 in the left side of the experimental sample was
77.9 degrees, compared with a mean of 85.1 degrees
obtained for the same side in the matched control
group. The mean increase of 7.2 degrees in the dis-
toangular malposition of the developing MnP2 in PDC
patients was highly statistically significant (P Ͻ .0001).
Thus, the first hypothesis, that the distal angulation
of the MnP2 is significantly greater in children with
PDC than in age- and sex-matched controls, is retained.
The difference between sides within the PDC sample
calls for an intrapatient comparison to test whether this
difference is of significance. Using a paired t-test, we
found no significant difference between the right side
and the left side. Pearson correlation was found to be
0.57, significant at the 0.01 level (P ϭ .0004).
The distribution of the MnP2 dental developmental
stage in the PDC sample according to Koch classifi-
cation was as follows: Of 23 patients showing MnP2
malposition, 61% were at stage E and 39% at stage
F, while out of 20 patients showing normal inclination
of the MnP2, 25% were at stage E, and 75% were at
stage F. These results show that the average dental
age is delayed in patients who show both abnormali-
ties (malposed MnP2 and PDC) compared with pa-
tients who show PDC anomaly but with normal incli-
nation of MnP2. Our second hypothesis that delayed
tooth formation is a significantly more frequent finding
in children with both malposed MnP2 and PDC is thus
retained.
DISCUSSION
This study was designed to test the null hypothesis
that angular malposition of unerupted MnP2 is not di-
rectly associated with PDC. The results suggest a sta-
tistically significant association between these 2 con-
ditions.
The palatally displaced canine is a maxillary dental
anomaly, whereas MnP2 is a mandibular anomaly.
Hence common mechanical cause is unlikely. The ab-
sence of a shared mechanical cause suggests asso-
ciation through a common genetic disorder. Peck et
al16
have already suggested that the homeobox gene
MSX1 may be involved in the genetic control of PDC.
The association of MSX1 with agenesis17
and with
clefting18
has been established in genetic linkage anal-
yses. Both agenesis and clefting have been shown to
be associated with the MnP2 malposition anomaly.1,15
Results of this work, along with results from Shalish et
al,1,15
associate the MnP2 angulation anomaly with
PDC, agenesis, and clefting, suggesting the MnP2
anomaly is a variable in a genetically related group of
dental anomalies likely to be associated with MSX1
mutations. It is likely that the MnP2 anomaly may ap-
4. 799MALPOSITION OF MANDIBULAR SECOND PREMOLAR IN PDC
Angle Orthodontist, Vol 79, No 4, 2009
pear in combination with any other of these inter-as-
sociated anomalies (eg, infraocclusion, mesially ectop-
ic maxillary first molar, tooth transposition, tooth rota-
tion, tooth size reduction, peg-shaped maxillary lateral
incisor), perhaps because all of these anomalies are
caused by the same mechanism. What could be this
mechanism?
Delayed tooth formation was reported in children
with clefting,19
with PDC,11,12
and with malposition of
MnP2.13
It therefore seems possible that the common
mechanism is a delay in tooth formation. If this is cor-
rect, one should expect a longer delay to increase the
likelihood of anomalies and thereby the likelihood that
more than 1 anomaly will be observed in the same
patient. This means that children who show more than
1 anomaly should also show a greater delay in tooth
formation. Indeed, an average greater delay was con-
firmed in this study in children showing both PDC and
MnP2 anomalies, compared with children showing
PDC but with a normal inclination of MnP2.
CONCLUSION
• PDC and MnP2 malposition anomalies are signifi-
cantly statistically associated, despite their taking
place on opposite jaws, suggesting a common ge-
netic etiology.
• Although 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.
• These findings suggest a delay in tooth formation as
a possible common genetic mechanism for these 2
malposition anomalies.
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HK. MSX1 mutation is associated with orofacial clefting and
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lip/plate. Am J Orthod Dentofacial Orthop. 1986;90:11–18.