Does age influence deep overbite correction with Invisalign? A prospective study evaluating mandibular incisor intrusion in adolescents vs adults

OBJECTIVE

To compare the accuracy of mandibular incisor intrusion with Invisalign (Align Technology, Santa Clara, Calif) in adolescents to that in adults.

MATERIALS AND METHODS

This prospective clinical study included 58 patients treated with either Invisalign Teen or Invisalign Full. Mandibular central and lateral incisors were measured on digital models created from intraoral scans. Predicted values were determined by superimposing the initial and final ClinCheck models, and achieved values were determined by superimposing the initial ClinCheck models and the digital models from the final scans. Individual teeth were superimposed with a best-fit analysis and measured using Compare software (version 8.1; GeoDigm, Falcon Heights, Minn).

RESULTS

The mean accuracies of mandibular incisor intrusion were 63.5% in adolescents and 45.3% in adults, and this difference was statistically significant. The amounts of achieved intrusion were 1.7 mm in adolescents and 0.9 mm in adults, and this difference was also statistically significant. Overall, there was a weak negative correlation between age and accuracy; as age advanced, the accuracy of mandibular incisor intrusion diminished slightly.

CONCLUSIONS

Mandibular incisor intrusion with Invisalign is significantly more accurate in adolescents than in adults. Orthodontists could contemplate reducing the degree of overcorrection for mandibular incisor intrusion in adolescents with deep overbites undergoing Invisalign Teen but still implementing the reverse curve of Spee mechanics.

The effect of vertical skeletal proportions on overbite changes in untreated adolescents: a longitudinal evaluation

OBJECTIVES

To evaluate the change in overbite within an untreated cohort from 9 to 18 years of age and to compare age-related changes in overbite depth based on vertical skeletal proportion.

MATERIALS AND METHODS

Lateral cephalograms were obtained from the American Association of Orthodontists Foundation (AAOF) Craniofacial Growth Legacy Collection Project. All cephalometric outcome measures were assessed at ages 9-11 (T1), 13-15 (T2), and 17-19 (T3) years. Generalized estimating equation (GEE) regression models were fit to examine the effect of MP-SN on overbite adjusted for age and gender.

RESULTS

A total of 130 subjects from the Denver, Bolton Brush, and Oregon Growth Studies were included. Overbite was relatively constant from T1 to T3 irrespective of facial type, with a minor decrease (0.15 mm) being observed overall. There was a transient increase between T1 and T2 (0.31 mm) that was canceled out by changes during later adolescence. Based on the GEE regression model adjusted for time and gender, a minor but statistically significantly greater reduction in overbite arose as MP-SN increased (coefficient = -0.080; 95% confidence interval -0.12, -0.04; P < .01).

CONCLUSIONS

In hyperdivergent subjects, a marginal decrease in overbite was observed from 9 to 18 years of age, with a transient increase from the period spanning 9-11 years to 13-15 years, which was negated in later adolescence. There are limited data to suggest that observation of vertical growth is required in most patients with marginally increased vertical facial proportions in the juvenile and pubertal phases.

Predicted overbite and overjet changes with the Invisalign appliance: a validation study

OBJECTIVES

To investigate whether the predicted changes in overbite (OB) and overjet (OJ) in Align Technology's (Santa Jose, Calif) digital treatment plan for the prescribed course of treatment with the Invisalign appliance were consistent with those same changes in OB and OJ measured with the Geomagic Control X (Geomagic US, Research, Triangle Park, NC) metrology software system.

MATERIALS AND METHODS

Geomagic Control X software was used to determine OB and OJ differences between the pretreatment and predicted outcome. STL files for patients satisfying inclusion criteria and undergoing nonextraction orthodontic treatment with the Invisalign appliance. The differences were compared, using the Bland-Altman analysis, to the corresponding data provided by Align Technology's digital treatment-planning interface, ClinCheck.

RESULTS

Data regarding 76 adult patients who satisfied strict inclusion criteria were assessed. The Shapiro-Wilks test indicated normality (P > .05). The Bland-Altman analysis showed high levels of agreement between the two measurements, with a bias range of -0.131 to 0.111 for OB and -0.393 to 0.03 for OJ recorded.

CONCLUSIONS

Clinicians and researchers can be confident that measurement data provided by Invisalign's ClinCheck digital treatment-planning facility concerning OB and OJ changes from the initial to the predicted treatment outcome are valid.

Predicted and achieved overjet and overbite measurements with the Invisalign appliance: a retrospective study

OBJECTIVES

To determine whether achieved outcome regarding overjet and overbite matched the predicted outcome following treatment with Invisalign (Align Technology, San Jose, Calif) aligner appliances.

MATERIALS AND METHODS

Data including pretreatment, predicted and achieved overjet, and overbite measurements provided by Align's digital treatment facility, ClinCheck Pro, were evaluated. Descriptive statistics, Mann-Whitney U-test, and Wilcoxon rank-sum intraclass correlation (ICC) test results were calculated.

RESULTS

From an initial sample of 600, 355 adult patients satisfied the inclusion and exclusion criteria. ICC scores for data input were excellent. Median (interquartile range [IQR]) age was 30.14 (23.33, 39.92) years and most (n = 259; 72.95%) were women. Almost one-third (n = 101; 28.45%) had undergone extraction as part of their treatment. More aligners were prescribed in the initial digital treatment plan for patients (median, 44; IQR: 35, 51.5; minimum, 17; maximum, 92) undergoing extractions as part of their orthodontic treatment than those who were not (median, 24; IQR: 18.25, 32; minimum, 13; maximum, 85) (P < .0001). Planned changes in overjet differed significantly from achieved outcomes (P < .001). Planned increases in overbite resulted in up to more than twice (222.72%) as much increase than predicted. Planned reduction of overbite achieved 8.69% of its predicted reduction in extraction cases.

CONCLUSIONS

Achieved overjet and overbite measurements differed significantly from the predicted outcomes at the end of an initial sequence of aligners. Planned increases in overbite resulted in greater overbite correction than predicted, particularly in extraction cases. Planned overbite reduction was challenging, especially in patients with extractions.

The Stability of Anterior Open Bite Closure After Bimaxillary Osteotomy

Introduction

The aim of this study was to evaluate the long-term success rate of combined surgical-orthodontic therapy of skeletal anterior open bite.

Materials and Methods

A total of 11 patients with an anterior open bite treated with a combined surgical-orthodontic therapy were retrospectively analysed via lateral cephalometric radiographs and models before treatment, 7-10 days after surgery (T1), one year post-operatively (T2) and two years post-operatively (T3).

Results

Ten patients continued to experience a positive overbite at T2. This decreased to 8 at T3. Three patients experienced relapse and had a negative overbite at T3. The average pre-treatment overbite was greater in the positive overbite group compared to the relapse group. Spearman's correlation analysis revealed a correlation between preoperative maxilla-mandibular plane angle (MMPA) with the overall change in overbite. Friedman's test followed by Bonferroni post-hoc analysis was carried out to identify any statistical significance.

Conclusion

In conclusion, combined surgical-orthodontic treatment achieves good results for anterior open bite. Patients with a high pre-operative MMPA have a higher risk of relapse. Lower anterior facial height ratio to total anterior facial height (LAFH/TAFH) and the amount of impaction do not significantly contribute to the risk of relapse. Long-term stability of overbite for anterior open bite patients should be around 75%.

Evaluation of efficacy of utility arch with inter-maxillary elastics for treating skeletal deep bite with retroclined upper incisors in the mixed dentition: a clinical randomized controlled trial

OBJECTIVES

To investigate the effectiveness of utility arch (UA) with inter-maxillary elastics compared with fixed anterior bite plane (FABP) for treating deep bite in brachy-facial children.

MATERIALS AND METHODS

This was a single-center, randomized controlled trial. Participants were children aged between 9 and 12 years with deep bite and a hypodivergent skeletal pattern. The sample was divided into the following two groups: (1) a UA group that was composed of patients with UAs with posterior inter-maxillary elastics and (2) an FABP group as a control. Outcomes were skeletal and dentoalveolar variables on cephalometric X-rays.

RESULTS

A total of 28 patients (13 boys, 15 girls) with a mean age of 10.66 years were enrolled. The treatment duration was 8.16 months in the UA group and 7.22 months in the FABP group. After treatment, the angle between the anterior cranial base and the mandible in the vertical plane increased significantly (P = .000) in both groups (about 1.97 degrees in the UA group and 2.75 degrees in the FABP group). Overbite decreased significantly in both groups (-2.1 m in the UA group and -3.64 m in the FABP group), but it decreased less significantly in the UA group than in the FABP group. The upper incisors flared significantly after treatment with both appliances (6.6 degrees in the UA group and 5.9 degrees in the FABP group).

CONCLUSIONS

Treatment of deep bite in children with a horizontal growth pattern by each of the appliances used in this study is effective. The mandible showed minor, significant backward rotation after treatment. The overbite decreased less in the UA group than in the FABP group.

Reverse Forsus vs. facemask/rapid palatal expansion appliances in growing subjects with mild class III malocclusions : A randomized controlled clinical study

PURPOSE

To investigate the skeletal, dental, and soft tissue effects of reverse Forsus (RF; 3M Unitek, Monrovia, CA, USA) and facemask/rapid palatal expansion (FM/RPE) appliances in growing subjects with class III malocclusions.

METHODS

The data of this prospective randomized controlled trial (RCT) were derived from pre- and posttreatment/observation lateral cephalograms of 45 subjects with mild class III malocclusions: group 1 (8 girls, 7 boys; mean age 10.54 years) received a FM/RPE appliance; group 2 (6 girls, 9 boys; mean age 10.49 years) received the RF appliance; and an untreated control group (7 girls, 8 boys; mean age 10.66 years) was matched to the treatment groups with regard to sagittal skeletal and dental classifications. Angular and linear measurements were evaluated using lateral cephalograms. Statistical analyses were performed by one-way analysis of variance, Kolmogorov-Smirnov test, Kruskal-Wallis, paired-samples t‑test, and Wilcoxon test, whereby p < 0.05 was accepted to be statistically significant.

RESULTS

The intermaxillary (ANB), interdental (overjet), and sagittal lip relations in the FM/RPE and RF groups showed significant improvements compared to the control group (p < 0.05). Although the anterior and inferior traction of the maxilla was greater in the FM/RPE group compared to the RF group (p < 0.05), both treatment groups showed similar clockwise rotation of the mandible compared to the control group. While significantly more proclination of maxillary incisors occurred in the RF group compared to the FM/RPE and control groups (p < 0.05), both treatments led to significantly retroclined mandibular incisors compared to the control group (p < 0.001).

CONCLUSION

Both therapies led to intermaxillary and interdental improvements. The RF appliance had a limited effect on the maxilla and it mostly had dentoalveolar effects when compared to FM/RPE therapy.

Changes in incisor relationship over the life course - Findings from a cohort study

OBJECTIVE

The aim of this longitudinal cohort study was to investigate the changes in incisor relationship over three decades from adolescence to mid-adulthood.

MATERIALS AND METHODS

The sample included 1,037 children (48.4% female) born between April 1972 and March 1973 from the longitudinal birth cohort Dunedin Multidisciplinary Health and Development Study. Overjet and overbite values were assessed at age 15 and 45 years and entered in a regression model as outcome variables. Baseline occlusal variables, sex, history of orthodontic treatment, periodontal data recorded at age 38, and self-reported oral parafunction and orthodontic treatment history recorded at age 45 were entered as covariates in the regression analysis.

RESULTS

Regression modelling showed that overjet/overbite category (high or low) at age 15 tends to predict overjet/overbite category at age 45, with overjet become slightly larger (around +0.5mm) and overbite slightly lower (-0.5mm) over time. Study members with self-reported tooth clenching had a slighter greater overbite (+0.3mm) at age 45 than those who did not. Additionally, those with signs of periodontal disease at age 38 had a slightly larger overjet (+0.5mm) at age 45 than those without disease. Sex differences were demonstrated with females having 0.6 mm larger overjet, and 0.4 mm overbite at age 45.

CONCLUSIONS

Overall, overjet values tend to be higher during mid-adulthood than during adolescence, while the converse is true for overbite. There appears to be a degree of sexual dimorphism in overjet and overbite values later in life.

CLINICAL SIGNIFICANCE

Incisor relationships change during the life course and are related to ageing, sex, periodontal health, and parafunctional habits. Clinicians and educators should be aware of these changes when making treatment decisions that alter incisor relationship.

Descriptive epidemiology of dental malocclusion in Najran patients seeking orthodontic treatment

Background

Untreated malocclusion can lead to compromised aesthetic function, depression, and low self-esteem. The aim of this study was to evaluate dental malocclusion in Najran, Saudi Arabia as no data existed before.

Method

This was a retrospective study analyzing the casts of all patients in Najran, Kingdom of Saudi Arabia, seeking orthodontic management for malocclusion between 2017 and 2019.

Measurements

The consultant orthodontist is the single investigator involved in collecting the details of demographics followed by molar relationships, overjet, overbite, crowding and spacing using digital caliper on each dental cast. Data were analyzed using IBM SPSS Statistics for IOS Version 25 (Armonk, NY: IBM Corp.

Results

A total of 326 patients sought treatment for different types of malocclusion. There were 143 males and 183 females with an M:F ratio of 1:1.3. Age ranged from 6 to 55 years with a mean SD of 22.6 ± 8.98. The prevalence for Class I, II and III malocclusions at 95% CI was (0.76 (0.757, 0.774)), 0.251 (0.243, 0.260) and 0.529 (0.519, 0.539) respectively. Fifty-one (15.6%) patients had reversed overjet, 65 (19.9%) reduced overjet, and 86 (26.4%) increased overjet. One hundred and sixty-four (50.3%) cases of reduced overbite and 99 (30.4%) cases of deep overbite were also observed. Tooth size arch length discrepancy were noticed with crowding and spacing in 83 (26.4%) and 71 (21.8%) patients, respectively.

Conclusions

This study has shown the prevalence of Class I, Class II, and Class III malocclusion to be 72.7%, 11.6% and 15.6% respectively. Increased over jet and crowding was demonstrated in more patients, though it is not statistically significant.

Efficacy of elastodontic devices in overjet and overbite reduction assessed by computer-aid evaluation

BACKGROUND

This study aimed to verify the efficacy of two elastodontic devices in overjet (OJ) and overbite (OB) reduction during treatment with the Equilibrator Series II (Eptamed) and Occlus-o-Guide (Sweden & Martina) devices.

METHOD

Sixty patients aged 7-15 years were enrolled in the study, and were divided into test and control groups. The test group included 30 patients (14 males, 16 females; mean age, 10.66 ± 2.12 years) treated with the EQ (Equilibrator) Series II. The control group included 30 patients (15 males, 15 females; mean age, 10.76 ± 2.52 years) treated with the Occlus-o-Guide. The two groups exhibited the same orthodontic features. The orthodontic criteria were: skeletal and dental class II malocclusion (divisions 1 and 2); and the presence of OJ and OB. Evaluation of OJ and OB was performed at two timepoints: T0 (before starting therapy) and T1 (after 1 year).

RESULTS

At T0, OJ and OB were similar for the two groups; however, at T1, both OJ and OB were significantly lower with the Eptamed device compared to the Occlus-o-Guide device (p = 0.0019).

CONCLUSIONS

Elastodontic devices improve orthodontic outcomes by aiding orthodontic patient management, diagnosis, and treatment planning, reducing the risk relapse acting on the whole organism and the rehabilitation of the tongue.

[Multipurpose miniscrews: combined canine disimpaction and malocclusion correction]

The objective of this case series was to show how only one miniscrew can be used to treat simultaneously or successively canine impaction and different malocclusions. Three patients aged of 13 years old who had malocclusions, such as Class II, overbite and canine impaction, were each one treated with the same miniscrew throughout the treatment period. Palatal miniscrews were placed mesially to the first molar and used as a direct or indirect anchorage depending on the moment of the treatment. In each case, satisfactory treatment was obtained with correction of overbite, class II malocclusion and canine impaction. The first steps of treatment were aesthetic for the patient and did not require patient cooperation.

Relationships between the upper central incisor crown forms and degree of labial inclination, overbite, and overjet in Japanese young adults

PURPOSE

The present study aimed to investigate the relationships between the crown form of the upper central incisor and their labial inclination, overbite, and overjet.

MATERIALS AND METHODS

Maxillary and mandibular casts of 169 healthy dentitions were subjected to 3D dental scanning, and analyzed using CAD software. The crown forms were divided into tapered, square, and ovoid based on the mesiodistal dimensions at 20% of the crown height to that at 40%. The degree of labial inclination of the upper central incisor was defined as the angle between the occlusal plane and the line connecting the incisal edge and tooth cervix. The incisal edges of the right upper and lower central incisor that in contact with lines parallel to the occlusal plane were used to determine the overbite and overjet. One-way ANOVA was performed to compare the labial inclination, overbite, and overjet among the crown forms.

RESULTS

The crown forms were classified into three types; crown forms with a 20%/40% dimension ratio of 1.00±0.01 were defined as square, >1.01 as tapered, and <0.99 as ovoid. The labial inclination degree was the greatest in tapered and the least in square. Both overbite and overjet in tapered and ovoid were higher than those in square.

CONCLUSION

Upper central incisor crown forms were related to their labial inclination, overbite, and overjet. It was suggested that the labial inclination, overbite, and overjet should be taken into consideration for the prosthetic treatment or restoring the front teeth crowns.

One versus two anterior miniscrews for correcting upper incisor overbite and angulation: a retrospective comparative study

Background

Miniscrews are effective devices for performing upper incisor intrusion. Different mechanics can be applied depending on the treatment objectives. This study aimed to evaluate the efficacy of one or two anterior miniscrews for upper incisor correction in cases of overbite and angulation in adult patients.

Methods

Forty-four adults with deep overbite were divided into two groups: group 1 was treated with one miniscrew between upper central incisors and group 2 with two miniscrews between upper lateral incisors and canines. Incisor intrusion and length were measured from lateral cephalograms before treatment, after treatment and at least 12 months into retention (T0, T1 and T2). Forces were applied (90 g) from the miniscrews to the archwire using elastomeric chains. ANOVA analysis was used to determine whether differences between evaluation times were statistically significant.

Results

Mean root resorption was 2.15 ± 0.85 mm, which ceased after active treatment. Overbite mean correction was − 3.23 ± 1.73 mm with no statistically significant relapse. Overbite correction and incisor intrusion were significantly greater in group 2 (− 3.80 ± 1.43 versus − 2.75 ± 1.63 for OB and 8.19 ± 3.66 versus 5.69 ± 2.66 for intrusion). Resorption and overbite correction were positively related. No counterclockwise rotation of the mandibular plane was observed.

Conclusions

Overbite correction can be performed by means of upper incisor intrusion without rotation of the mandibular plane. Correction of upper incisor intrusion and overbite is greater in patients treated with two miniscrews. The increase in upper incisor buccal angulation is greater with one miniscrew. Root resorption is positively related to the extent of intrusion. Stability is satisfactory regardless of whether one or two miniscrews are used.

A prospective clinical trial of the effects produced by the Connecticut intrusion arch on the maxillary dental arch

OBJECTIVE

To assess and compare the effects produced in the maxillary dental arch by means of Connecticut intrusion arch (CIA) with or without a cinch back on the distal end of the tube of the first molars.

MATERIALS AND METHODS

This study included 44 patients with a mean age of 13.1 ± 1.8 years treated for deep bite with a CIA randomly divided into two groups: group 1 (G1), 22 patients with initial mean age of 12.72 ± 1.74 years treated with the CIA in the upper arch without a cinch back on the distal surface of the tube of the first molars, and group 2 (G2), 22 patients with an initial mean age of 13.67 ± 2.03 years treated with the CIA with a cinch back. Lateral cephalograms were available before treatment (T1) and after intrusion of maxillary incisors (T2). The mean treatment period was 5.5 ± 1.45 months. Intragroup and intergroup changes in the maxillary incisor and molar positions were analyzed by paired and independent t-tests associated with the Holm-Bonferroni correction method for multiple comparisons (P < .05).

RESULTS

There were significant differences between groups in terms of maxillary incisor displacement. The maxillary incisors flared labially (2.17°) and proclined (1.68 mm) in group 1, whereas a palatal inclination (-1.99°) and retroclination (-1.13 mm) was observed in group 2. No significant differences were found for the molar positions between the groups.

CONCLUSIONS

The presence or absence of a distal bend in CIA affects incisor tipping and proclination during intrusion mechanics.

Controlling incisor torque with completely customized lingual appliances

PURPOSE

To test the null hypothesis of no significant deviation between the center of rotation (C_ROT) and the center of resistance (C_RES) during space closure in Angle class II division 2 subjects achieved using a completely customized lingual appliance (CCLA) in combination with class II elastics and elastic chains.

METHODS

This retrospective study included 29 patients (male/female 11/18; mean age 15.6 [13-27] years) with inclusion criteria of an Angle class II/2 occlusion of least of half of a cusp, maxillary dental arch spacing, completed CCLA treatment (WIN, DW Lingual Systems, Bad Essen, Germany) in one center with a standardized archwire sequence and use of class II elastics and elastic chains only. Maxillary incisor root inclination was assessed by X‑ray superimpositions of the maxilla at the beginning (T1) and the end (T3) of CCLA treatment. Using Keynote software (Apple®, Cupertino, CA, USA), the incisor's C_ROT was assessed with the point of intersection of the incisor axes (T1; T3) following vertical correction of overbite changes. C_RES was defined at 36% of the incisor's apex-incisal edge distance.

RESULTS

The null hypothesis was rejected: the mean C_ROT - C_RES difference was 52.6% (p < 0.001). The mean C_ROT was located at 88.6% (min-max 51-100%) of the incisor's apex-incisal edge distance. Although 6.9% of C_ROT were located between the C_RES and the alveolar crest, the vast majority (93.1%) were assessed between the alveolar crest and the incisal edge, or beyond.

CONCLUSION

CCLAs can create upper incisor palatal root torque even in cases in which lingually oriented forces applied incisally to the center of resistance of the upper incisors counteract these intended root movements.

The effect of overbite and overjet on clinical parameters of periodontal disease: A case control study

•

Malocclusion contributes in the development of periodontal diseases due to incomplete oral hygiene.

•

Over bite and over jet contribute differently to periodontal health status.

•

There lies a significant correlation between malocclusion and periodontal disease.

•

There is a need to correct overjet and overbite activities among individuals to control the prevalence of periodontal disease.

Aim

To investigate the association of overjet and overbite with clinical parameters of periodontal disease.

Material and methods

The study was performed in Riyadh, Saudi Arabia, from March 2017 to March 2018. 600 Saudi males aged 20–30 years old were included. Participants were divided into three groups (n: 200) depending on the presence of overjet (OJ) or overbite (OB) and its relationship with periodontal disease. Periodontal parameters were assessed clinically and radiographically. One-way analysis of variance was used to test for any significant differences between groups. Tukey’s post hoc comparison test was used to evaluate correlations among parameters.

Results

OJ exceeding 8 mm was correlated with debris, calculus, and periodontal scores on mandibular anterior teeth, especially on the lingual surfaces.

Both OJ and OB groups showed significantly increased PD, compared to that of the control group in measurement at the lingual (P = 0.004, 0.003) and proximal (P = 0.002, 0.002) surfaces of the lower anterior teeth. Finally, the CEJ-AB was statistically significantly higher in the OB group compared to the OJ and control groups (P = 0.091, 0.008).

Conclusion

The present study found a correlation between OJ and OB and periodontal disease, as measured using specific parameters. This indicates that periodontal treatment may be insufficient unless the overjet or overbite is corrected.

The variability of the curve of Spee : An analysis of multiple setups of the same Angle Class I patient case

PURPOSE

The aim of this study was to examine possible parameters correlating to the shape of the curve of Spee (COS) by analyzing multiple setups of the same Angle class I patient case.

METHODS

In all, 65 setups of the same Angle class I patient case were constructed. We measured the depth of the COS, length and width of the dental arch, steps, rotations, spaces and symmetry of the constructed setups. With a correlation analysis, possible relationships between the depth of the COS and measured parameters were evaluated.

RESULTS

The COS in the constructed setups was more exaggerated than in the reference case but none of the measured parameters correlated to the depth of the COS. The largest deviation was found on the mesiobuccal cusp tip of the first molar (-0.5 ± 0.4 mm left side; -0.8 ± 0.5 mm right side). This study found a negative correlation between the length and width of the lower dental arch (r = -0.61). While maintaining Angle class I, a large spread width of the depth of the COS, the dental arch width and length was shown.

CONCLUSION

The different manifestations of the COS in this study show the freedom of arrangement of the individual tooth morphology without exhibiting a correlation to parameters of the dental arch.

Does overbite reduction affect smile esthetics?

OBJECTIVES

To compare the effects of two common methods of overbite reduction on smile esthetics.

MATERIALS AND METHODS

A prospective clinical trial was conducted with 32 patients in whom overbite reduction was achieved using a maxillary incisor intrusion arch (18 patients) or flat anterior bite plate (14 patients). Clinical and cephalometric records were compared pretreatment (T1), after overbite reduction (T2), and posttreatment (T3).

RESULTS

Both treatment groups experienced a reduction in overbite and maxillary and mandibular incisor proclination during treatment (T1-T3). The center of resistance of the maxillary incisor and the incisal edge was significantly intruded in the intrusion arch group during overbite reduction (T1-T2). However, most of the intrusion of the center of resistance was lost by the end of treatment (T2-T3). Both treatment groups experienced a reduction in maxillary incisor display and flattening of the smile arc during overbite reduction.

CONCLUSIONS

Both overbite reduction methods caused a decrease in incisor display and flattening of the smile arc. Smiles were improved in some patients by the end of treatment. However, reduction in incisor display persisted. Clinicians should take precautions to prevent negative effects of overbite reduction.

Comparison of Canine Overlap in Pediatric Patients Requiring Stainless Steel Crown Placement under General Anesthesia before and after the Procedure

Objectives

Despite the increasing popularity of pediatric dental treatments under general anesthesia, information is scarce regarding occlusal changes in patients receiving stainless steel crowns (SSCs) under general anesthesia. This study sought to compare canine overlap before and after general anesthesia in children receiving SSCs. In case of a change, the possibility of returning to the preoperative state and the time required for this process were also evaluated.

Materials and Methods

This interventional, before-and-after study was performed on 60 children between 2 to 7 years of age requiring dental treatment under general anesthesia. The contact point of the most prominent area of the maxillary primary canine and mandibular primary canine was marked before and immediately after general anesthesia and at one and two weeks postoperatively. The change in canine overlap was analyzed using repeated measures analysis of variance (ANOVA) and linear regression test.

Results

Canine overlap significantly decreased immediately after general anesthesia (P<0.05). The mean bite opening was 0.51±0.22 mm at the site of the right canine and 0.50±0.185 mm at the site of the left canine. These values returned to their normal preoperative state after one week (P<0.05). Repeated measures ANOVA showed significant differences in this respect between the time points (P=0.002).

Conclusion

The occlusion and vertical dimension of pediatric patients may change following dental treatment under general anesthesia; the magnitude of change in canine overlap may vary depending on the class of occlusion and number of SSCs placed. These changes are temporary and often resolve within a week.

Influence of tooth position on wind instrumentalists' performance and embouchure comfort : A systematic review

PURPOSE

To systematically search the scientific literature concerning the influence of tooth position on wind instrumentalists' performance and embouchure comfort.

METHODS

The PubMed, Cochrane, and Embase databases were searched up to November 2017. The main orthodontic journals were searched for papers older than the inception date of PubMed. Grey literature was sought via Google Scholar. Eligible studies were critically appraised and analysed.

RESULTS

The searches retrieved 54 papers. Only two met the inclusion criteria. Searching the orthodontic journals and Google Scholar resulted in two additional eligible studies. All four studies had a cross-sectional design. The sample sizes ranged from 20-100 participants, varying from children to professional musicians. Because of a large heterogeneity in outcome variables, no meta-analysis could be performed. Descriptive analysis shows that there are indications that tooth irregularities have a negative influence on embouchure comfort and performance of a wind instrument player. A large overjet may impede the embouchure of brass musicians and may have a negative influence on trumpet player performance. A wide jaw form seems more beneficial to trumpet player performance than a small jaw form. Furthermore, players of all types of wind instruments can experience embouchure difficulties from extreme spacing or an open bite.

CONCLUSION

Tooth position can influence musical performance and embouchure comfort of wind instrumentalists. A Class I relationship without malocclusion seems appropriate for every type of wind instrument. The more extreme the malocclusion, the greater the interference with wind instrumentalists' performance and embouchure comfort. Evidence however is limited.

A comparative study of the effect of the intrusion arch and straight wire mechanics on incisor root resorption: A randomized, controlled trial

OBJECTIVE

To analyze and compare external apical root resorption (EARR) of maxillary incisors treated by intrusion arch or continuous archwire mechanics.

MATERIALS AND METHODS

This cone-beam computed tomography (CBCT) study analyzed 28 deep bite patients in the permanent dentition who were randomly divided into two groups: Group 1, 12 patients with initial mean age of 15.1 ± 1.6 years and mean overbite of 4.6 ± 1.2 mm treated with the Connecticut intrusion arch (CIA) in the upper arch (Ortho Organizers, Carlsbad, Calif) for a mean period of 5.8 ± 1.27 months. Group 2, 16 patients with initial mean age of 22.1 ± 5.7 years and mean overbite of 4.1 ± 1.1 mm treated with conventional leveling and alignment using continuous archwire mechanics for 6.1 ± 0.81 months. The degree of EARR was detected in 112 maxillary incisors by using CBCT scans and a three-dimensional program (Dolphin 11.7, Dolphin Imaging & Management Solutions, Chatsworth, Calif). The CBCT scans were obtained before (T1) and 6 months after initiation of treatment (T2). Differences between and within groups were assessed by nonpaired and paired t-tests, respectively, with a 5% significance level.

RESULTS

Significant differences were found for both groups between T1 and T2 ( P < .05) indicating that EARR occurred in both groups. However, there were no significant differences when EARR was compared between group 1 (-0.76 mm) and group 2 (-0.59 mm).

CONCLUSIONS

The Connecticut intrusion arch did not lead to greater EARR of maxillary incisors when compared with conventional orthodontic mechanics.

The Invisalign Appliance Could Be an Effective Modality for Treating Overbite Malocclusions Within a Mild to Moderate Range

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Management of overbite with the Invisalign appliance. Khosravi R, Cohanim B, Hujoel P, Daher S, Neal M, Liu W, Huang G. Am J Orthod Dentofacial Orthop 2017;151:691-9.

SOURCE OF FUNDING

This study was supported by the University of Washington Orthodontic Alumni Association TYPE OF STUDY/DESIGN: A retrospective study.

Association of overjet and overbite with esthetic impairments of oral health-related quality of life

OBJECTIVE

Esthetics is an important part of quality of life and a frequent reason for orthodontic treatment demand. It was the aim of this study to investigate whether esthetic impairments, related to overjet and overbite, can be assessed with an established oral health-related quality of life instrument.

MATERIALS AND METHODS

Data from 1968 participants (age: 16-90 years; 69.8% female) from three German surveys were analyzed. Esthetic impairments of oral health-related quality of life were measured with four questions of the Oral Health Impact profile (OHIP), which comprise esthetic aspects of oral health-related quality of life. Higher values represent greater esthetic impairment (sum score: 0-16). Overbite and overjet values were categorized (≤ - 1 mm, 0-1 mm, 2-3 mm, 4-5 mm, ≥ 6 mm). The specific impact of each category on esthetic impairment, in relation to the reference category (2-3 mm), was calculated in linear regression analyses. The type of relationship and the specific impact of overbite and overjet were evaluated in regression analyses with fractional polynomials.

RESULTS

Overbite ranged from - 5 to 15 mm (mean: 3.2 mm) and overjet from - 7 to 19 mm (mean: 3.1 mm). Both an increase and a decrease in overjet, in relation to the reference category, resulted in more esthetic-related oral health-related quality of life impairments. However, in this model, only the effect for increased overjet was statistically significant (4-5 mm: + 0.4 OHIP points; ≥ 6 mm: + 0.9 OHIP points). In the regression analysis with fractional polynomials, both an increase and a decrease in overjet resulted in more esthetic impairments, characterized by a U-shaped relationship. No association could be verified for overbite.

CONCLUSION

A substantial increase or decrease of overjet from the reference values is associated with esthetic impairments of oral health-related quality of life, whereas the extent of overbite seems to have no impact on esthetics.

The influence of occlusal morphology on occlusion time

OBJECTIVES

The aim of the study was to assess how the morphology of the occlusal surfaces of premolars and molars influenced the occlusion time in a mixed gender group of young adults with full natural dentition.

METHODS

Fifty healthy volunteers with Angle's Class I occlusion were included in the study. After clinical examination, the alginate impressions of both arches were taken, and plaster casts were prepared. To assess the morphology of lateral teeth, the digital models were measured. Occlusal analysis was performed with the T-Scan^® III to assess occlusion time.

RESULTS

A direct correlation was found between the cusp distance for the first upper premolar and occlusion time (r = -0.29, p<0.05) and the distance between distal buccal and distal lingual cusps of the first lower premolar and occlusion time (r = 0.33, p<0.05). The parameters that had their impact on occlusion time were the opening angle of lingual cusps for the lower molars and the furrow angle of aperture between cusps for first upper premolar.

DISCUSSION

Occlusal surface morphologies of premolars may have direct impact on occlusion time. However, anterior guidance parameters and morphologies of molars could also influence the time teeth are in contact coming to maximal intercuspation.

Components of overbite correction in lingual orthodontics: molar extrusion or incisor intrusion?

OBJECTIVE

The aim of this study was to evaluate the components of overbite correction with the lingual Incognito(®) technique.

MATERIALS AND METHODS

The study was based on 45 files of patients with overbite treated with the Incognito(®) technique. The evaluation of overbite correction is assessed by comparing lateral cephalograms before and after treatment using QuickCeph 2000(®) software. All the statistical calculations were performed using Statview II software for Mac(®).

RESULTS

The results revealed the efficiency of the Incognito(®) technique in overbite correction despite the absence of bite planes in the majority of cases. The components of this correction are, in order: intrusion of mandibular incisors, extrusion of mandibular molars, weak extrusion of maxillary molars and stability of the maxillary incisors. These were the results commonly found in previous studies on small samples. The study also demonstrated an increase of lower face height in extraction and non-extraction cases.

CONCLUSION

The Incognito(®) technique is very efficient in overbite correction. As the main component of overbite correction is mandibular incisor intrusion, it seems crucial from the esthetic point of view to evaluate the smile line when overbite correction is needed.

Occlusal characteristics of deaf-mute individuals in the Turkish population

OBJECTIVES

To classify and determine the occlusal characteristics of deaf-mute individuals and its gender distribution in the Turkish population.

METHODS

For this study, 213 deaf-mute individuals (155 boys and 58 girls) were evaluated. The age range was between 10-24 years, and the mean age was 16.37+/-2.53 years. Measurements were divided into four groups: dental, intraarch, interarch, and, extra data.

RESULTS

Of the participants, 75.0% had a Class I molar relationship, whereas 13.0% and 8.0% had Class II and Class III malocclusions, respectively. 23.9% of individuals had a normal overbite, 38.4% had a deepbite, and 23.4% had an openbite. One or more congenitally missing teeth were found in 6.0% of individuals; 81.0% expressed satisfaction with their esthetics, and 19.0% expressed the contrary.

CONCLUSIONS

Different characteristics and malocclusions are present in deaf-mute individuals.