Removable thermoplastic appliances as orthodontic retainers--a prospective study of different wear regimens

The aim of this prospective study was to evaluate and compare stability after 6 months of Essix retainer use. Patients' perceptions of wearing the retainer were also evaluated. A total of 69 patients, 53 girls and 16 boys [mean age 15.7 years, standard deviation (SD) 1.96], were included in the study and randomized into two groups with different wear regimens; full-time wear for 3 months and thereafter at night (group A) compared to full-time wear for 1 week and thereafter at night only (group B). Sixty patients completed the study and thus, group A comprised 30 maxillary retainers and 18 mandibular retainers and group B 30 maxillary and 18 mandibular retainers. Little's irregularity index (LII), overjet, and overbite were measured at debond (T(1)) and after 6 months (T(2)). Differences within and between groups were analysed with a Mann-Whitney test. At T(2), all patients completed a questionnaire in order to evaluate their experience of wearing an Essix retainer and how they complied with the given instructions. Differences in LII during T(1)-T(2) were 0.44 and 0.49 mm for group A and B, respectively, but with no significant difference between the groups. There were also no significant changes in overjet and overbite within or between the groups during T(1)-T(2). According to the responses to the questionnaire, the retainer was well tolerated by the patients. It was therefore concluded that the Essix retainer is sufficient for maintaining the results after orthodontic treatment and that night-time wear is adequate.     

Twenty-year follow-up of functional treatment with a bionator appliance: A retrospective dental cast analysis

Objective:To investigate changes in dental arch configuration, relationship, and malocclusion directly after Class II malocclusion treatment with a Balters bionator modified by Ascher as well as 20 years after treatment.Materials and Methods:Orthodontic dental cast analysis of 18 patients with skeletal Class II treated with a bionator without any additional fixed therapy was performed with a digital caliper at three stages: before (T0), after (T1) and 20 years after (T2) treatment. Arch perimeter and depth, intermolar and intercanine distance, overjet, overbite, sagittal molar and canine relationship, mandibular incisor irregularity (Little''s index), and malocclusion (PAR index) were assessed.Results:During treatment (T0–T1), upper arch perimeter significantly increased with a significant decrease in the upper and lower arch perimeter long-term (T1–T2), whereas corresponding arch depths changed only slightly in both periods. Transverse intermolar width increased significantly during treatment, remaining almost constant from T1 to T2. Lower intercanine distance remained fairly unchanged during treatment, but decreased significantly during follow-up. Lower incisor irregularity improved slightly during treatment but increased significantly long-term. After treatment, sagittal molar relationships on both sides were improved, overjet and overbite reduced; these significant changes remained stable long-term. The peer assessment rating (PAR) index was significantly lower after treatment and increased insignificantly during follow-up.Conclusions:20 years after bionator treatment without additional fixed appliances, the improved sagittal relationship and the reduced overjet and PAR index remained fairly stable. Long-term changes are most likely due to physiological aging processes and are not associated with bionator treatment.     

Long-Term Effects of Rapid Maxillary Expansion Followed by Fixed Appliances

Objective:To evaluate the long-term changes in maxillary arch widths, overjet, and overbite in patients who were treated with rapid maxillary expansion (RME) followed by edgewise appliances.Materials and Methods:The material for the study consisted of study casts taken from 41 patients (19 males, 22 females) on four different occasions (before treatment, T1; after RME, T2; after treatment, T3; and during follow-up period, T4). The upper intercanine, interpremolar, and intermolar widths and overjet and overbite were measured on each set of study casts. Mean age of the subjects was 13.2 ± 1.3 years (range, 11.2–16.9 years) at T1, 13.3 ± 1.3 years (range, 11.3–17 years) at T2, 15.5 ± 1.4 years (range, 13.1–18.8 years) at T3, and 20.4 ± 1.6 years (range, 17.9–24.8 years) at T4.Results:The net increase in intercanine width, interpremolar width, intermolar width, overjet, and overbite was 1.4 ± 2.4 mm, 4.6 ± 2.6 mm, 4.3 ± 2.5 mm, 0.1 ± 0.6 mm, and 0.2 ± 0.6 mm, respectively, and the relapse rates were 37% for intercanine width, 19% for interpremolar width, and 17% for intermolar width at the end of the follow-up period.Conclusions:A significant amount of relapse occurred in maxillary arch widths at the postretention assessment, the greatest being in intercanine width. RME significantly decreased overbite and increased overjet, and a statistically significant decrease was observed in both overbite and overjet at the postretention assessment.     

Age-Related Long-Term Posttreatment Occlusal and Arch Changes

Objective:To evaluate differences in long-term postretention changes between adolescents and adults.Materials and Methods:The sample included 96 subjects, 51 adolescents and 45 adults (14.2 ± 0.8 and 21.5 ± 6.8 years of age, respectively, at the end of treatment) retained for 3 years and followed approximately 16 years post treatment, who were randomly selected from two private practices. Prior to treatment, 38 and 58 had Class I and Class II malocclusions, respectively.Results:With the exception of adult midlines, all of the occlusal variables (overjet [0.50–0.77 mm], overbite [0.85–0.95 mm], the maxillary incisor irregularity [0.69–0.80 mm], the mandibular incisor irregularity [0.85–1.50 mm] and the PAR score [0.86–1.92 points]) showed significant increases over time. Adolescents consistently showed greater increases of the occlusal variables than adults, with mandibular incisor irregularity and the PAR index attaining statistically significant (P < .05) levels. Arch length and mandibular intercanine width showed statistically significant decreases over time in both groups; maxillary intercanine and intermolar widths did not change significantly. Overjet increased significantly more in Class II patients than in Class I patients, whereas Class I patients showed significantly greater decreases in mandibular intermolar width than Class II patients.Conclusions:Over the 16-year posttreatment period, adolescents showed significantly greater increases in mandibular incisor irregularity, and the PAR index than adults. Treated Class I patients demonstrated less increase in overjet and greater decreases in mandibular intermolar width than Class II patients.     

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

PURPOSEThe 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 METHODSMaxillary 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.RESULTSThe 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.CONCLUSIONUpper 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.     

Dimensional changes of dental arches produced by fixed and removable palatal cribs: A prospective,randomized, controlled study

Objective:To evaluate the dimensional changes of dental arches on digital models of open bite treatment with fixed and removable palatal cribs.Materials and Methods:The sample comprised 41 patients of both sexes who were white, aged 7–10 years, and who had mixed dentition, Angle Class I molar relationship, and a negative overbite of at least 1 mm. The sample was randomly divided into two groups: G1, fixed palatal crib; and G2, removable palatal crib. Cast models, obtained initially (T1) and after 1 year of treatment (T2), were scanned by a three-dimensional (3D) scanner, 3Shape R700, producing a 3D image. Measurements were performed by a calibrated examiner using OrthoAnalyzer™ 3D software.Results:At T2–T1, differences were observed between the groups regarding vertical dentoalveolar development and overjet. There was more mandibular incisor extrusion for G1 (−1.66 mm) than for G2 (−0.54 mm). An overjet increase was observed in G1 (0.56 mm), in contrast to a reduction in G2 (−0.40 mm). There was a similar overbite increase for both groups (3.51 mm for fixed palatal crib and 3.88 mm for removable palatal crib).Conclusions:Both the treatment protocols are similarly effective for anterior open bite correction, providing an overbite increase with dentoalveolar arch changes, especially in the anterior region.     

Patient compliance with Hawley retainers fitted with the SMART® sensor: A prospective clinical pilot study

Objective:To evaluate the compliance of patients while wearing maxillary Hawley retainers embedded with SMART microsensors.Methods:The sample population consisted of 22 patients who were divided into an experimental (group A) and a control group (group B). Group A was informed that they would be monitored through the use of SMART microsensors, while group B was not informed that they would be monitored. After the delivery of the retainers (T0), the patients were evaluated at T1 and T2, represented by 6- and 12-week follow-up visits, respectively. At T1, group B was informed of our ability to monitor their compliance. Both groups continued wearing their retainers during T1 to T2.Results:During T0–T1, Group A wore their retainers for an average of 16.3 hours (SD 4.39), while group B wore their appliances for an average of 10.6 hours (SD 5.36, t  =  2.426, P  =  .027). Although group B increased their retainer wear by 0.5 hours/day from T1 to T2, this increase was not statistically significant.Conclusions:Despite significant differences being noted between the two groups at T1, group B did not show significant mean changes in their wear time before and after becoming aware of the use of the SMART microsensor.     

Dentoskeletal effects produced by a Jasper Jumper with an anterior bite plane

Objective:The aim of this retrospective study was to evaluate the dentoskeletal effects produced by a modified Jasper Jumper with an anterior bite plane for the correction of Class II division 1 malocclusion.Materials and Methods:A sample of 32 growing patients (mean age  =  11.9 ± 1.4 years) with Class II division 1 malocclusion and increased overbite were treated with a modified Jasper Jumper (JJ) and anterior bite plane protocol and compared with a matched control group of 30 subjects with untreated Class II malocclusion (mean age 12.2 ± 0.8 years). Lateral cephalograms were taken before treatment (T1) and at the end of comprehensive treatment (T2). Mean treatment duration was 2.1 ± 0.4 years. The T1–T2 changes in the two groups were compared with Student’s t-tests for independent samples.Results:The JJ group was successfully treated to a Class I occlusal relationship with a significant reduction in overjet (–3.9 mm, P < .001) and overbite (–3.1 mm, P < .001). The JJ group exhibited a significant increase in mandibular length and a significant improvement in maxillomandibular sagittal skeletal relationships. The lower incisors were significantly proclined, while the lower first molars demonstrated significant movement in a mesial direction.Conclusions:Use of a modified JJ appliance and anterior bite plane is an effective protocol for the treatment of Class II malocclusion with increased overbite and greater skeletal (75%) than dentoalveolar (25%) effects mainly at the mandibular level.     

Long-term stability of the leveling of the curve of Spee.

The aim of the study was to investigate whether the orthodontic leveling of the curve of Spee is a treatment procedure with a stable result on a long-term basis. Measurements were made on the plaster casts of 149 orthodontically treated patients (57 males and 92 females). The mean age before treatment was 12.8 years (range, 8-25 years). Study casts were taken before treatment (T1), at the completion of orthodontic therapy (T2), and 6.7 years (mean) posttreatment (T3). Inclusion criteria were no extractions, all Angle classifications except Class III malocclusions, and all permanent teeth fully erupted except second and third molars. The curve of Spee and the irregularity index were measured on standardized digital photographs of the casts. Overjet and overbite were assessed with a ruler. Changes in the curve of Spee were correlated with changes in irregularity index, overjet, and overbite from T1 to T3. The following results were noted: (1) leveling of the curve of Spee is a relatively stable treatment procedure compared with a return of incisor crowding and deepening of the bite; (2) neither the initial depth of the curve of Spee nor the initial irregularity index is an indicator for the amount of relapse; (3) the amount of leveling is not correlated with the relapse of the 4 tested parameters (curve of Spee, irregularity index, overjet, and overbite); and (4) there is a mild correlation between the relapse of the curve of Spee and the relapse of the irregularity index, overjet, and overbite. According to the results of the study, leveling the curve of Spee during orthodontic treatment seems to be very stable on a long-term basis; it was weakly correlated with the other variables tested.     

Twelve-year follow-up of mandibular incisor stability: Comparison between two bonded lingual orthodontic retainers

Objective:To compare the long-term outcome 9 years after removal of two different types of fixed retainers used for stabilization of the mandibular anterior segment.Materials and Methods:Sixty-four children who had undergone orthodontic treatment with fixed appliances in both arches were divided into two groups depending on which kind of retainer being used. Twenty-eight of the patients had a canine-to-canine retainer bonded to the canines and 36 had a bonded twistflex retainer 3-3, bonded to each tooth. Measurements were made on study models and lateral head radiographs, before and after treatment, 6 years after treatment, and 12 years after treatment, with a mean of 9.2 years after removal of the retainers.Results:No significant differences were found between the two groups at the long-term follow-up according to Little''s Irregularity Index or available space for the mandibular incisors. The overjet and overbite were reduced after treatment in both groups and stayed stable throughout the observation period. Also, no differences in bonding failures between the two retainers were found.Conclusions:Both a canine-to-canine retainer bonded only to the canines and a twistflex retainer 3-3 bonded to each tooth can be recommended. However, neither of the retention types prevented long-term changes of mandibular incisor irregularity or available space for the mandibular incisors after removal of the retainers.     

A new method of evaluating posterior occlusion and its relation to posttreatment occlusal changes.

The purpose of this study was to assess the relationship between posterior occlusion and posttreatment changes in other occlusal variables. Pretreatment (T1), posttreatment (T2), and postretention (T3) records were obtained for 49 Class I (n = 23) and Class II (n = 26) extraction cases. Overbite, overjet, mandibular incisor irregularity, right and left molar deviations, midline deviation, and mandibular arch length were measured, and occlusal registrations were made of each set of dental casts. The proximity of posterior occlusal surfaces was measured as the contact or near-contact areas at or below 300 microm thickness, based on the optical densities of scanned images of the posterior occlusal registrations. The treatment changes for overbite, overjet, right and left molar deviation, and arch length were significantly greater in the Class II group, and the reductions in incisor irregularity were greater in the Class I group. No other class differences were found. Overbite, overjet, and incisor irregularity increased after treatment, and arch length continued to decrease, with no significant class differences. Contact and near-contact areas at or below 300 microm constituted 7% of the functional occlusal table for both classes at the end of treatment, having decreased significantly in both groups (21% in Class I and 29% in Class II) during treatment. Because contact and near-contact areas increased in some patients and decreased in others, there were no significant posttreatment changes. Negative correlations were found between contact and near-contact areas at T2 and changes in overjet from T2 to T3, and between contact and near-contact areas at T3 and changes in overbite from T2 to T3. No relationships were found between posterior contact and near-contact area and incisor irregularity. We concluded that (1) the area of actual and near contacts at or below 300 microm decreased significantly with treatment, indicating that, despite excellent treatment results by conventional standards, the proximity of posterior occlusal surfaces lessened; (2) the proximity of the posterior occlusal surfaces should not be expected to increase posttreatment; (3) posttreatment contact and near-contact areas may be factors in overbite and overjet stability; and (4) posttreatment contact and near-contact areas are not related to incisor irregularity.     

Stability of anterior crossbite correction: A randomized controlled trial with a 2-year follow-up

Objective:To compare and evaluate the stability of correction of anterior crossbite in the mixed dentition by fixed or removable appliance therapy.Material and Methods:The subjects were 64 consecutive patients who met the following inclusion criteria: early to late mixed dentition, anterior crossbite affecting one or more incisors, no inherent skeletal Class III discrepancy, moderate space deficiency, a nonextraction treatment plan, and no previous orthodontic treatment. The study was designed as a randomized controlled trial with two parallel arms. The patients were randomized for treatment with a removable appliance with protruding springs or with a fixed appliance with multibrackets. The outcome measures were success rates for crossbite correction, overjet, overbite, and arch length. Measurements were made on study casts before treatment (T0), at the end of the retention period (T1), and 2 years after retention (T2).Results:At T1 the anterior crossbite had been corrected in all patients in the fixed appliance group and all except one in the removable appliance group. At T2, almost all treatment results remained stable and equal in both groups. From T0 to T1, minor differences were observed between the fixed and removable appliance groups with respect to changes in overjet, overbite, and arch length measurements. These changes had no clinical implications and remained unaltered at T2.Conclusions:In the mixed dentition, anterior crossbite affecting one or more incisors can be successfully corrected by either fixed or removable appliances with similar long-term stability; thus, either type of appliance can be recommended.     

Retrospective Analysis of Casts to Assess Cervical Headgear Treatment in the Presence of Vertical Growth Pattern

Abstract Objective: Does molar distalization as effected by cervical headgear increase the vertical dimension of occlusion in patients with vertical growth pattern? Materials and Methods: A sample of 86 patients with neutral and vertical growth pattern in the late mixed dentition stage underwent headgear treatment. Their initial and intermediary casts were retrospectively analyzed for occlusal relationships at the maxillary first molars and degrees of overjet and overbite. The only cases included were those in which headgear treatment was carried on for at least 6 months, achieving a minimum distalization of 4 mm. The intermediary casts were fabricated after headgear treatment had been completed and prior to the initiation of multiband treatment.Patients were divided into three groups (N, V1 and V2) according to the degrees of vertical growth pattern, which were determined based on y-axis angle values. Results: Grouped by degrees of vertical growth, the data revealed occlusal relationship changes of 6–8 mm and overjet reductions of 0.6–1.2 mm. The overbite changes were unexpectedly small (0–0.04 mm).Grouped by degrees of overbite, the data revealed that headgear treatment increased the vertical dimension of occlusion in deep-bite patients (> 4 mm), while giving rise to decreases in patients with overbites of < 3 mm.     

Digital images as an alternative to orthodontic casts in assessing malocclusion and orthodontic treatment need

Objective. To investigate the potential use of two-dimensional digital images as an alternative to orthodontic casts in the assessment of malocclusion and orthodoantic treatment need. Material and Methods. Assessment of malocclusion (Angle's classification of molars, overjet, and overbite) and orthodontic treatment need (Index of Orthodontic Treatment Need (IOTN): Dental Health Component (DHC) and Aesthetic Component (AC)) was conducted on 313 study casts and their images by two trained and calibrated examiners. Agreement of orthodontic treatment need and Angle's molar classification was assessed employing Kappa statistics (κ). Agreement of overjet and overbite (measured in mm) was assessed in comparison and correlation analyses. Inter- and intra-examiner reliability of assessment was investigated. Results. There was substantial agreement of the molar relationship classifications (κ >0.70), orthodontic treatment need as assessed by IOTN-DHC (κ =0.79) and IOTN-AC (κ =0.56) between measurements obtained from orthodontic casts and their images. There was also substantial agreement of measurements of overjet and overbite as obtained from orthodontic casts and their images. The standardized directional differences of overjet and overbite were ≤0.2. The intra-class correlation coefficients of assessments of overjet and overbite obtained from orthodontic casts and their images were >0.90. Inter- and intra-examiner reliability for the assessment of malocclusion and orthodontic treatment need was acceptable. Conclusion. Two-dimensional digital images can be used as an alternative to casts in assessment of malocclusion and orthodontic treatment need.     

Incisor inclination changes produced by two compliance-free Class II correction protocols for the treatment of mild to moderate Class II malocclusions

Objective:To compare the changes in incisor inclination between two compliance-free Class II correction protocols for the treatment of mild to moderate Class II malocclusions.Materials and Methods:Among Class II malocclusion patients a total of 38 consecutive patients treated with the Xbow appliance and later with full brackets (XB) were compared to 36 consecutive patients treated with Forsus connected to the archwire while on full brackets (FO). Evaluated cephalometric variables were overjet, overbite, skeletal Class II, lower incisor inclination, and upper incisor inclination. Factors that were analyzed were gender, treatment type, age at start of treatment (T1), and treatment length. Independent t-tests, χ², multiple analysis of variance, and Pearson correlations were applied.Results:No differences in incisor inclination between both treatment protocols were identified. At T1 no statistical difference for any cephalometric variable was demonstrated with regard to gender and treatment type. Gender was also not associated with a different treatment time or age at T1. The mean treatment time was 24.2 months for XB and 30.2 months for the FO group (P  =  .037). XB patients averaged 10 fewer months of fixed edgewise appliances compared to FO patients. Neither gender nor treatment type had any influence on the changes of the evaluated dependent variables between T1 and the end of treatment. Lower incisors proclined more the longer the treatment (P  =  .005). Both overjet and upper incisor inclination were affected by age at T1 (P  =  .001 and P  =  .014, respectively).Conclusions:Both compliance-free Class II correction protocols for the treatment of mild to moderate Class II malocclusions appear to generate the same amount of incisor inclination. Large variability was identified.     

Pattern and amount of change after orthodontic correction of upper front teeth 7 years postretention

Objective:To investigate the amount and pattern of changes of maxillary front teeth 7 years postretention, which previously were retained with a bonded retainer.Materials and Methods:The study group consisted of 27 patients. Study models before treatment (T1), at debonding (T2), 1 year after removal of the upper bonded retainer (T3), and 7 years postretention (T4) were present. The irregularity index (sum of contact point displacements) and the rotations of front teeth toward the raphe line were calculated.Results:The irregularity index of the maxillary front teeth changes very little or not at all during the first year postretention. Further change long term resulted in an irregularity index of mean 2.0 (range 0.0–5.8). The contact relationship between the laterals and centrals seems to be the most critical. Forty rotated teeth in 21 patients were corrected more than 20°. Mean relapse during the first year postretention was 6.7° (range 0.0°–14.7°). Mean changes during 7 years was 8.2° (range 0.0°–19.3°).Conclusions:Relapse of upper front teeth retained with a bonded retainer is minor in both the short and long term. If permanent retention is required after 3 years of retention, it is enough to retain the incisors.     

Longitudinal study of cephalometric soft tissue profile traits between the ages of 6 and 18 years

Objective:To study the longitudinal changes in 19 soft tissue cephalometric traits (according to the Bergman cephalometric soft tissue facial analysis).Materials and Methods:Cephalograms and photographs of 40 subjects (20 male, 20 female, from the Burlington Growth Centre) that were obtained at ages 6, 9, 12, 14, 16, and 18 years were used. Subjects were orthodontically untreated whites and had Class I dentoskeletal relationships (ideal overjet and overbite). Images were obtained with the lips in a relaxed position or lightly touching.Results:Three groups of soft tissue traits were identified: (1) traits that increased in size with growth (nasal projection, lower face height, chin projection, chin-throat length, upper and lower lip thickness, upper lip length, and lower lip–chin length); (2) traits that decreased in size with growth (interlabial gap and mandibular sulcus contour [only in females]); and (3) traits that remained relatively constant during growth (facial profile angle, nasolabial angle, lower face percentage, chin-throat/lower face height percentage, lower face–throat angle, upper incisor exposure, maxillary sulcus contour, and upper and lower lip protrusion).Conclusion:Current findings identify areas of growth and change in individuals with Class I skeletal and dental relationships with ideal overjet and overbite and should be considered during treatment planning of orthodontic and orthognathic patients.     

Association between malocclusion in the mixed dentition with breastfeeding and past nonnutritive sucking habits in school-age children

ObjectivesTo evaluate the association between malocclusion characteristics in the mixed dentition stage, breastfeeding, and past nonnutritive sucking habits in school-age children.Materials and MethodsA total of 547 school children in the mixed dentition, in the age range between 7 and 13 years, were evaluated by means of questionnaire and clinical examination. Binomial and multinomial logistic regression models were used to evaluate the associations between breastfeeding and finger and pacifier sucking habits, the malocclusion characteristics of posterior crossbite, and excessive or deficient overjet and overbite.ResultsIndividuals who had nonnutritive sucking habits had 2.16 times greater chance of having anterior open bite (odds ratio [OR] 2.16; 95% confidence interval [CI], 1.07–4.33) and 2.39 times greater chance of having posterior crossbite (OR 2.39; 95% CI, 1.56–5.49). Children who were exclusively breastfed up to at least 6 months of age had a higher frequency of normality for overjet and overbite and the lowest posterior crossbite index. However, in adjusted analysis, breastfeeding showed no association with malocclusion characteristics in the mixed dentition stage.ConclusionsBreastfeeding was not associated with the presence of malocclusion in the mixed dentition, whereas past nonnutritive sucking habits were associated with the occurrence of malocclusion.     

Stability of orthodontic treatment outcomes after 1-year treatment with the eruption guidance appliance in the early mixed dentition: A follow-up study

Objectives:To investigate occlusal stability from the early mixed to the permanent dentition in children after early treatment with the eruption guidance appliance (EGA).Materials and Methods:Of 46 participants who received 1-year early EGA treatment, 35 attended a follow-up examination at age 12. Group 1 (n = 21) started their EGA treatment at mean age 7.7 years, and group 2 at 9.1 years. Following 1-year treatment, the EGA was used as a retainer. Changes in overjet, overbite, sagittal molar relationship, and anterior crowding were measured on casts obtained before EGA treatment, after EGA treatment, and at follow-up to evaluate occlusal stability.Results:Mean overjet, overbite, sagittal molar relation, and mandibular crowding improved significantly during the study period. Participants with good compliance during the retention period had significantly smaller overjet and overbite values than those with poor compliance.Conclusions:Early correction of increased overjet, overbite, and class II molar relation with the EGA is maintainable and can also be effective in the permanent dentition, provided the EGA is worn regularly as a retainer.     

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.