Pulsating forces were applied to a patient's maxillary molar to induce piezoelectricity and accelerate tooth movement. Piezoelectricity generates charges when bone deforms under mechanical stress, inducing microcurrents that may stimulate bone remodeling. A device applied 30 oz peak (20 oz average) pulsating forces at 0.7 Hz to the test tooth, and 18 oz continuous force to the control tooth. Over 180 hours, the pulsed tooth moved 0.056 inches, more than the control. Mobility was also lower for the pulsed tooth. Precise measurements showed pulsating forces may achieve faster, less painful orthodontic tooth movement through piezoelectric effects.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.)
This journal club presents a case of prosthetic
rehabilitation of an amputated thumb. It emphasizes that
prosthetic replacement is a better option for aesthetic and
psychological improvement, particularly in cases where the
victim is unwilling to undergo complicated surgical procedures for reconstruction of thumb or where functioning
of thumb cannot be restored even by multiple surgeries. In
the present case, a 20 years old female patient, with
missing thumb of her right hand was rehabilitated aesthetically by a non-invasive and cost effective prosthetic
procedure by using heat temperature vulcanizing silicone
material. The prosthesis (the thumb) was attached using
medical adhesives. On 3 months recall appointment, no
complications were observed. The prosthesis was in good
shape and required no further intervention. The prosthetic
thumb lacks the sensation of a normal or reconstructed
thumb, although it does not require the multiple procedures
of surgical reconstruction and the accompanying loss of
time for rehabilitation and healing
Orthodontic tooth movement is basically a biologic response towards a mechanical force. Osteoclast and osteoblast cells mediate bone resorption and apposition, which eventually produces tooth movement. Researches showed that the rate of orthodontic tooth movement can be altered by certain drugs locally or systemically. The Objective of this article is to discuss the current data concerning the effect of drugs on orthodontic tooth movement.
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.
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.
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.
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.
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.
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.
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.
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.
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.)
This journal club presents a case of prosthetic
rehabilitation of an amputated thumb. It emphasizes that
prosthetic replacement is a better option for aesthetic and
psychological improvement, particularly in cases where the
victim is unwilling to undergo complicated surgical procedures for reconstruction of thumb or where functioning
of thumb cannot be restored even by multiple surgeries. In
the present case, a 20 years old female patient, with
missing thumb of her right hand was rehabilitated aesthetically by a non-invasive and cost effective prosthetic
procedure by using heat temperature vulcanizing silicone
material. The prosthesis (the thumb) was attached using
medical adhesives. On 3 months recall appointment, no
complications were observed. The prosthesis was in good
shape and required no further intervention. The prosthetic
thumb lacks the sensation of a normal or reconstructed
thumb, although it does not require the multiple procedures
of surgical reconstruction and the accompanying loss of
time for rehabilitation and healing
Orthodontic tooth movement is basically a biologic response towards a mechanical force. Osteoclast and osteoblast cells mediate bone resorption and apposition, which eventually produces tooth movement. Researches showed that the rate of orthodontic tooth movement can be altered by certain drugs locally or systemically. The Objective of this article is to discuss the current data concerning the effect of drugs on orthodontic tooth movement.
Optimal force /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
Optimal force /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
Effect of lacebacks in maxillary canine retraction /certified fixed orthodont...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
Space closure2 /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
biomechanics of space closure in orthodonticcs / fixed orthodontics coursesIndian dental academy
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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.
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
- 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
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
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
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
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
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
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!
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
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Orthodontic movement using pulsating force induced peizoelctricity
1. Orthodontic movement using pulsating
force-induced piexoelectricity
E. Shapiro, F. W. Roeber, and L. S. Klempner
Boston. Mass.
Piezoelectricity may be a means of achieving physiologic tooth movement.
The generation of piezoelectricity in response to the mechanical deformation of bone has
been reported by a number of researchers. l-6 When bone is deformed, there are generated
piezoelectric charges which vary directly with the magnitude of the induced stress.6 These
charges induce microcurrents to flow through bone and soft tissue’ and may enhance tooth
movement by stimulating osteoblastic and osteoclastic activity. The microcurrents flow
only during the application or release of stress6 and are not observed where continuous
orthodontic forces are used. It is believed that the inducement of piezoelectric charges by
the application of pulses of force to teeth can achieve and accelerate osteogenic response.
In this study, tooth movement is evaluated as pulsating (intermittent) forces are applied to
maxillary molars with the ultimate objective of achieving physiologic tooth movement.
Background
Yasuda and associates’ exerted pressure on a femur and observed callus formation in
the periosteum and endosteum. Potentials were negative for bone under compression and
positive for bone under tension, thus demonstrating that mechanical forces can induce a
polarized electric surface charge. Further investigations of Fukada and Yasuda* attributed
the generation of piezoelectricity to the deformation of the crystalline structure of
collagen.
In a study of bone bending, Grimm4 found that bone may actually be under tension on
the classic “pressure” side and compression on the classic “tension” side. The advancing
tooth may “bend” the septal bone creating tension, thus producing the positive
piezoelectric charges associated with osteoclastic activity. The trailing wall is pulled by
the periodontal fibers causing alveolar bending, compression, negative piezoelectric
charges, and osteoblastic activity. In his investigation, Grimm speculated that orthodontic
tooth movement in response to a given force is related to the magnitude of alveolar
deflection and to root surface area. Grimm hypothesized that a strain-induced electrical
or chemical phenomenon may be the link between mechanotherapy and alveolar bone
response.
Cochrar? observed bone formation using the direct application of 10 microamperes of
current. Bassett7 concurred that direct current stimulates the rate of osteogenesis and
FromTufts University School of Dental Medicine.
Presented in part before the Research Section of the Northeastern Society of Orthodontists, New
York, N. Y., November, 1977.
This study was supported by Research Grant 1 Rol DE04487-01, National Institute of Dental Re-
search.
0002-9416/79/070059+08$00.80/O 0 1979 The C. V. Mosby Co. 59
2. Fig. 1. Vertical wires parallel to the long axes of molars for measurement of tooth tipping and transla-
tion. Wires were used only during measurement.
Fig. 2. Measuring apparatus attached to the anterior teeth for measuring movement of the wires shown
in Fig. 1.
further indicated that this rate was increased by uniphasic pulses. Friedenberg’ss implan-
tation of electrodes in the femora of rabbits determined that the application of 5 to 20
microampere current is optimal for osteogenic activity. Levy lodetermined mathematically
that an electrical stimulus having a frequency of 0.7 Hz should “elicit a maximum
response in bone,” and he substantiated this figure in subsequent experiments with canine
femora. He concluded that pulses of electrical current accelerate repair.
Methods and materials
Initial investigations were conducted on a 23-year-old Caucasian woman to compare
the effectiveness of using pulsating versus continuous forces to move contralateral molars
distally. Complete orthodontic records were prepared; these included study casts,
cephalometric and intraoral radiographs, and oriented photographic prints. In addition to
these routine records, apparatus was devised to obtain precise measurements of tooth
3. Volume 16
Number I
Pulsating force-induced piezoelectricity 61
Fig. 3. Tooth mobility sensor connected by a nylon line to the molar.
Fig. 4. Acrylic appliance with bands, actuator for pulsating force, and rod for continuous force.
position, angulation, and mobility on both the pulsed and the control teeth.
Tooth tipping and translation were monitored by measuring movement of the ends of a
vertical wire attached to the buccal surface of each molar and oriented parallel to the long
axis (Fig. 1). The measurement apparatus was affixed with an acrylic splint to the teeth
anterior to the molars (Fig. 2). These measurements were recorded in both the sagittal and
frontal planes. Positional and angular changes of both molar teeth were thus obtained.
A sensor was devised to record mobility of 0.00001 inch or greater. A nylon line
extended from the sensor to a vertical pin attached to the molar (Fig. 3). A strain gauge
affixed to the sensor converted movement of the tooth into electrical signals that were
recorded on an oscillograph. The mobility device is frictionless and imposes a negligible
force on the test tooth. Its low mass allows it to record the instantaneous movement of the
molar during pulsing. A standard mobility test was performed periodically by means of a
4. Fig. 5. Force applicator appliance with restraining headgear
wire plunger extending through the acrylic.appliance to the orthodontic band on the test
tooth. Mobility was monitored as an elastic activated the plunger. Comparison mobility
tests were conducted on both the control and the test teeth.
An acrylic appliance was designed to provide a platform from which to deliver the
forces (Fig. 4). To prevent anterior movement of the maxillary teeth, a Northwest type of
headgear was attached to the acrylic appliance (Fig. 5). Throughout the test period a
continuous force of 18ounces was applied to the control tooth, and a pulsating force of 30
ounces peak (20 ounces average) was applied to the test tooth. The force to the control
tooth was supplied by three elastics activating a wire plunger. The force to the test tooth
was supplied by a pneumatic actuator consisting of a cylindrical metal housing encasing a
piston. The cylindrical housing interlocks into a metal socket in the acrylic appliance, and
a rod attached to the piston extends to an orthodontic band on the molar (Fig. 6). A timing
circuit operates a pneumatic valve, thereby controlling the inlet of pressurized air into the
actuator. The magnitude of air pressure in the cylinder determines the amount of force
exerted on the molar. When the valve is closed, the air in the cylinder is allowed to leak
out at a controlled rate, decreasing the force on the tooth proportionately.
The system has been designed to operate in this manner to induce unidirectional
microcurrents in the alveolar bone. To achieve the maximum charge build-up and to
overcome charge neutralization, it is necessary to use a high rate of force application.6
Abrupt removal of the force would produce an opposite polarity charge and microcurrent
flow in the opposite direction.” In order to minimize the generation of an opposite
polarity-piezoelectric charge, the force is removed slowly, relieving the stress within the
bone7 (Fig. 7). Pulses are repeated at a frequency of 0.7 Hz.‘O Orthodontic elastics were
used to apply continuous forces to the control molar.
One of us (F. W. R.) conducted tests to determine the force decay of the elastics as
used on the control side. Three elastics were stretched the same distance as in the reported
study, thereby developing the force used on the control side. The following data were
obtained:
5. Volume 76
Number I
Pulsating force-induced piezoelectricity 63
Fig. 6. Pneumatic pulsating force actuator to move test molar.
Time (hrs.) Force (oz.)
0 20
I 20
9.5 20
20.0 19.75
24 19.75
Hence, the force decay was practically negligible, even after 24 hours. Previous
investigators have noted as much as 25 percent force reduction, but this decay was
probably because of elastics being used inside the mouth as opposed to extraoral use as in
this study. The test gauge incorporated a “last word indicator” commonly used in
deflection measurement.
Results
Pulses of force have produced sustained movement rates of 0.2-0.3 x 10-a inches per
hour when applied to the patient’s maxillary left second molar. Initial testing with 10
ounce pulses (6 ounces average) produced low and erratic rates of movement. By increas-
ing the pulsing force to above 8 ounces, 56 x lo-” inches of crown movement was
achieved during 180 hours of pulsing (Fig. 8). The test period extended over 40 nights for
an average of only 4.5 hours of pulsing per night.
A continuous force of 18ounces on the control tooth was 2 ounces less than the average
magnitude of the pulsed force. In pulsing, the peak force applied to the tooth was maintained
for 0.2 second and then slowly decreased during the remaining 1.2 seconds of the cycle to a
sustained level of 8ounces. During the cycle this produced an average force of 2Oounces on
the pulsed tooth. The rate of movement aswell asthe total movement of the pulsed tooth was
greater than the control tooth (Fig. 9). Throughout the experiment tooth mobility was
minimized when a sustained force of 8 ounces was maintained by the actuator.
The patient’s response to pulsating forces hasbeen favorable. Pain was experienced on
the control side from time to time throughout the experiment but not on the pulsed side.
The patient reported that the force pulsations were just barely perceptible, that she was not
usually aware of them, and that they did not interfere with sleep.
6. PULSATING FORCE PARAMETERS
( TRACE OF OSCILLOGRAPH RECORDING )
t
PEAK
FORCE
i
PULSE
-I-
4PPLICATION
I= PER’oD -4
DURATION OF CONTINUOUS PULSING
TIME
Flg. 7. Pulsating force parameters (tracing of oscillograph recording).
Period = Time between the leading edges of two successive pulses (1.4 seconds). Pulse application
rime = Time required to reach the peak force (20 msec.). Peak force = Maximum force level achieved
during the pulse cycle (900 Gm). Pulse width = Time duration of maximum force application (0.2
second). Force removal time = Trailing edge of the pulse extending from the end of the peak force
pulse to the beginning of the next pulse (1.2 seconds). Sustained force = Force still acting on tooth at
end of pulse period (240 Gm.). Duration of continuous pulsing = Number of pulses applied during a
treatment session, multiplied by the pulse period.
MOVEMENT OF PULSED 8 CONTROL TEETH
l Pulsed
60
100 200 300 400 500 600 700
HOURS OF TESTING
Fig. 8. Movement of pulsed and control teeth.
The accuracy of the measuring systems developed for the project permits precise
monitoring of patient responses and thus rapid evaluation of experimental parameters. The
accuracies of the measurement apparatus are kO.002 inch for position, kO.25 degree for
rotation, and +-0.001 inch for mobility. The mobility sensor system provides noise-free
oscillograph registrations of 0.06001 inch or more of crown movement, although we
record movement to the nearest 0.001 inch. The mobility measurements are made over
short intervals and are therefore not subject to temperature-induced changes of the nylon
line. The sensor exerts a constant fraction of an ounce of force on the line during the
mobility test and therefore does not subject the line to force gradients which would stretch
7. Volume 76
Number I
Pulsating force-induced piezoelectricity 65
RATE OF MOVEMENT
VS TOOTH MOVEMENT
l-
z
$i a .6- l Pulsed
$ $ 0P$- ,5- Conlrol
E” .4-
8” .3-
l-r.0
b w .2-
pz
*‘-
2
, ,+(fy-,
10 20 30 40 50 60 70 80 90 100
TOOTH MOVEMENT
1INCHES X 1O-3)
Fig. 9. Rate of movement versus tooth movement.
MOBILITY OF PULSED 8 CONTROL TEETH
l Pulsed
30- 0 Control
10
100 200 300 400 500 600 700
HOURS OF TESTING
Fig. 10. Mobility of pulsed and control teeth.
it at one time more than at any other time. Hence, reliable comparative measurements can
be made on the test and the control teeth.
The force applicator system has delivered more than 2.5 million pulses throughout the
testing without a failure.
Summary
According to Steinberg and associate? and Bassett,’ piezoelectric charges are gen-
erated in response to the mechanical deformation of bone and these charges induce
microcurrents to flow through bone and soft tissue. The direction of current, amperage,
and wave form are all critical considerations in maximizing the effects of piezoelectricity.
In summarizing recent concepts, CochratP recommends the direct application of a con-
tinuous or pulsed current of 10 microamperes to optimize bone deposition at the cathode.
Friedenberg’ss implantation of electrodes in the femora of rabbits determined an optimal
current of 5 to 20 microamperes for optimum bone formation, both osteoblastic and
osteoclastic. There is evidence that nonoscillatory electric fields and DC currents can be
osteogenic. Friedenberg and associates used DC currents.
8. Levy’” determined mathematically that a stimulus having a frequency of0.7 Hz should
“elicit a maximum response in bone.” and he substantiated this tigure in subsequent
experiments with canine femora. He concludes that the use of pulsed signal sources can
accelerate repair. Cochran points out that the frequency of 0.7 Hz corresponds closely
with the natural frequency of walking.
An appliance and instrumentation have been designed and constructed to apply pulsat-
ing forces for the distal movement of maxillary molars. Devices have been developed to
determine tooth position, angulation, or tipping and mobility-both static and dynamic.
These measurements are carried out to 0.002 inch, to 0.25 degree, and to 0.001 inch,
respectively. Clinical testing has been initiated on one patient, and sustained distal crown
movement has been indicated in 180 hours. Perhaps more data would enhance the study,
and at present additional subjects are being investigated. Although only one patient was
used in the present study, the data gathered will, as far as we know, represent the only
information reported in the literature on pulsating-force-induced movement of teeth. We
will conduct further investigations optimizing parameters of force magnitude, pulse dura-
tion and period, and force application and removal rates.
REFERENCES
1. Yasuda, I., Nogucki, K., and Sata, T.: Dynamic callus and electrical callus, J. Bone Joint Surg. 37A:
1291-1293, 1955.
2. Fukada, E., and Yasuda, I.: On the piezoelectric effect of bone, J. Physiol. Sot. Jpn. 12: 115% 1162, 1957.
3. Steinberg, M. E., Bosch, A., Schwan, A., and Glazer, R.: Electrical potentials in stressed bone, Clin.
Orthop. 61: 294-299, 1968.
4. Grimm, F. M.: Bone bending, a feature of orthodontic tooth movement, AM. J. ORTHOD. 62: 384-393,
1972.
5. Zengo, A. N., Pawluk, R. J., and Bassett, C. A. L.: Stress-induced bioelectric potentials in the dentoalveo-
lar complex, AM. J. ORTHOD. 64: 17-27, 1973.
6. Steinberg, M. E., Busenkell. G. L., Block, J., and Korostoff E.: Stress-induced potentials in moist bone in
vitro, J. Bone Joint Surg. 56: 704-713. 1974.
7. Bassett, C. A. L.: Biologic significance of piezoelectricity, Calcif. Tissue. Res. I: 252-272. 1968.
8. Cochran, G. V. B.: Experimental methods for stimulation of bone healing by means of electrical energy.
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