Skeletal and dental effects of function-generating bite appliance compared to rapid palatal expander and untreated controls.

INTRODUCTION: Maxillary expansion is a fundamental interceptive orthodontic treatment, which can be achieved through either a rapid expansion protocol or functional devices. However, no data exist about the efficacy of functional devices in achieving skeletal expansion. Therefore, the aim of this study was to compare the effects of the rapid palatal expander (RPE) and the function-generating bite type M (FGB-M) on the transversal dimension of the maxilla, and on the maxillary and mandibular dental arch width. METHODS: One hundred eighty-one skeletal Class I patients, aged between 6 and 12 years and with a cervical vertebral maturation stage II or III, with maxillary transversal deficiency were retrospectively enrolled; among these 55 were treated with FGB-M, 73 were treated with RPE and 51 were untreated subjects retrieved from historical databases. The pre-treatment (T0) and post-treatment (T1) frontal cephalograms were retrieved, and the maxillary and mandibular widths, and the distance between upper and lower first molars were measured. T1-T0 interval was of 17.3 months (RPE), 24.6 months (FGB-M) and 18.2 months (controls). RESULTS: The statistical analysis showed that there were no statistically significant differences between the RPE and FGB-M groups regarding skeletal and dental expansion, while the untreated control group differed significantly from the other two groups. CONCLUSION: The comparison between patients treated with RPE and FGB-M showed that there were no statistically significant differences between the RPE and FGB-M groups regarding the amount of skeletal expansion and dental arch width, suggesting that both appliances can be used to achieve similar results.

Comparison of maxillary transversal changes between auxiliary beta-titanium expansion arch and miniscrew-assisted rapid palatal expansion.

OBJECTIVE(S): This study compared buccal bone thickness, dental inclinations and maxillary transverse width dimensions changes between auxiliary beta-titanium expansion arch (AEA) and miniscrew-assisted rapid palatal expansion (MARPE). MATERIALS AND METHODS: The sample consisted of 29 patients, aged between 18 and 40 years, with transverse maxillary deficiency and treated without extractions, divided into two groups: group AEA: comprised 13 individuals (initial mean age: 29.23 ± 9.13 years) treated using auxiliary beta-titanium expansion arch; group MARPE: comprised 16 patients (initial mean age: 24.92 ± 7.60 years) treated with miniscrew-assisted rapid palatal expansion. Buccal bone thickness, dental inclinations and transverse width dimensions (dental, nasal base and jugular) were measured in cone-bean computed tomographies at pre- and post-treatment stages. The variables were compared using the independent t-test. RESULTS: The buccal bone thickness was similar for both groups at the post-treatment stage. The second premolars were significantly more buccal inclined in the AEA group and the right maxillary first molars in the MARPE group. The intercanine and intermolar distances were statistically significantly greater in the MARPE group. Changes in dental arch transverse dimensions were significantly greater for the MARPE group. CONCLUSION: Both treatment protocols corrected the maxillary transverse discrepancy; however, MARPE provided greater correction.

The coordination of bimaxillary alveolar arch widths in subjects with normal occlusion or posterior crossbite: A CBCT retrospective study.

OBJECTIVES: To propose a method for evaluating the coordination of maxillomandibular alveolar arch in transverse dimension with cone-beam computed tomography (CBCT) and to apply this method to subjects with normal occlusion at different dentition stages or transverse discrepancy. MATERIALS AND METHODS: Digital data of 130 patients with normal occlusion at different dentition stages or transverse discrepancy were collected for three-dimensional reconstruction. The patients with normal occlusion were divided into Group 1 (>16 years) and Group 2 (≤16 years) based on their age. Adult patients with posterior crossbite were divided into the Group 3. According to the proposed method, the average alveolar arch coordination angle (AACA) and other parameters were analysed in each group. Group 1 was considered as the control group and compared with Group 2 and Group 3. RESULTS: Significant differences were observed in the maxillary posterior segment width among patients with normal occlusion. Group 3 demonstrated increased AACA and mandibular alveolar arch width compared with the normal occlusion group. Pearson correlation analysis indicated a positive relationship between maxillomandibular alveolar arch widths in the normal occlusion groups, with a strong correlation between AACA and the disparity in maxillomandibular widths. CONCLUSION: Adults with normal occlusion exhibit significantly wider maxillary posterior alveolar arches than adolescents, with no marked difference in mandibular widths. The posterior crossbite group showed broader mandibular alveolar arches. There was a strong correlation between AACA and the difference in maxillomandibular widths. This study's method shows potential value for orthodontic transverse diagnosis.

The association between dental and dentoalveolar arch forms of children with normal occlusion and malocclusion: a cross-sectional study.

BACKGROUND: Symmetrical and coordinated dental and alveolar arches are crucial for achieving proper occlusion. This study aimed to explore the association between dental and dentoalveolar arch forms in children with both normal occlusion and malocclusion. METHODS: 209 normal occlusion subjects (5-13 years, mean 8.48 years) and 199 malocclusion subjects (5-12 years, mean 8.19 years) were included. The dentoalveolar arch form was characterized by the smoothest projected curve representing the layered contour of the buccal alveolar bone, referred to as the LiLo curve. Subsequently, a polynomial function was utilized to assess dental and dentoalveolar arch forms. To facilitate separate analyses of shape (depth/width ratio) and size (depth and width), the widths of dental and dentoalveolar arch forms were normalized. The normalized dental and dentoalveolar arch forms (shapes) were further classified into 6 groups, termed dental/dentoalveolar arch clusters, using the k-means algorithm. RESULTS: The association between dental and dentoalveolar arch clusters was found to be one-to-many rather than one-to-one. The mismatch between dental and dentoalveolar arch forms is common in malocclusion, affecting 11.4% of the maxilla and 9.2% of the mandible, respectively. CONCLUSIONS: There are large individual variations in the association between dental and dentoalveolar arch forms. Early orthodontic treatment may play an active role in coordinating the relationship between the dental and dentoalveolar arch forms.

Comparative evaluation of transverse width indices for diagnosing maxillary transverse deficiency.

OBJECTIVES: This study aimed to compare and evaluate different transverse width indices for diagnosing maxillary transverse deficiency (MTD), a common malocclusion characterized by uncoordinated dental arches, crossbites, and tooth crowding. MATERIALS AND METHODS: Sixty patients aged 7-12 years were included in the study, with 20 patients diagnosed with MTD and 40 normal controls. Transverse width indices, including maxillary width at the buccal alveolar crest and lingual midroot level, as well as at the jugal process width, were measured. Differences between these indices and their corresponding mandibular indices were used as standardized transverse width indices. The reference range of these indices was determined and evaluated. Receiver operating characteristic (ROC) analysis was performed to evaluate their diagnostic ability. RESULTS: The transverse width indices and standardized transverse width indices of the MTD group were significantly smaller than those of the control group, except for the jugal process width. The evaluation of the reference range and ROC analysis revealed that the difference of the maxillomandibular width at buccal alveolar crest was the most accurate diagnostic method. CONCLUSIONS: The jugal point analysis method may not be suitable for diagnosing MTD. Instead, measuring the difference in maxillomandibular width at the buccal alveolar crest proves to be a more reliable and accurate diagnostic method for MTD.

Credibility of Pont's index in Egyptian population.

BACKGROUND: Many indices have been suggested to help orthodontists in predicting the ideal dental arch width. One of these was Pont's index which was established by Pont. He suggested equations to predict the ideal maxillary dental arch width (interpremolar and intermolar) from the combined mesiodistal width of the maxillary incisors. This study aimed to test the applicability of Pont's index as an orthodontic diagnostic tool in Egyptian population and to compare the results with those obtained from studies of different ethnic subjects. METHODS: This study was performed using dental casts of 184 Egyptian individuals (82 males and 102 females; age range, 19-24 years). The casts were divided into 46 casts with normal occlusion, 46 casts with class I, 46 casts with class II and 46 casts with class III malocclusion, according to Angle's classification. Alginate impressions were taken for all patients and poured immediately using dental plaster. The real models were transformed into digital models using three-dimensional laser scanner to allow digital model analysis. Predicted arch widths were calculated using Pont's equations. The predicted values were compared to the measured values. RESULTS: Intra class correlation coefficient (ICC) (absolute agreement) between measured and predicted arch widths was determined. Poor absolute agreement was found between measured arch width values and the corresponding values calculated according to Pont's index. CONCLUSION: According to the results of this study, Pont's index is not a reliable method for predicting the ideal dental arch widths in Egyptian populations.

Intra-Lesional Injection of Triamcinolone to Palatoplasty Scar to Aid Reversal of Transverse Maxillary Relapse after Orthognathic Surgery.

ABSTRACT: A 32-year-old female with a repaired right unilateral cleft lip and palate underwent several surgical and orthodontic procedures during the rehabilitation process of her condition. Nine years after this extensive treatment she underwent transverse relapse of her maxilla and requested a consultation for its correction as she felt her speech and chewing were negatively affected. She presented with a transverse maxillary arch collapse on the cleft side with significant palatal scarring secondary to multiple palate procedures. A course of maxillary expansion and dental alignment with fixed orthodontic appliances was carried out. in addition, she had 2 triamcinolone injections 7 months apart while undergoing orthodontic treatment and one 10 months after completion to soften the scarred palatal tissues. The maxillary arch was successfully expanded and aligned. She was retained with a removable chrome cobalt palatal frame to be used full-time and assure stability of the correction. She has been followed for 4 years with no clinical evidence of relapse. Triamcinolone injection into significant palatal scarring in cleft palate patients with a decreased transverse maxillary dimension can be considered an adjunct procedure in conjunction with orthodontic treatment.

Long-term stability of curve of Spee levelled with continuous archwires in subjects with different vertical patterns: a retrospective study.

OBJECTIVES: The aim of the study was to evaluate the curve of Spee (COS) stability in patients treated with continuous archwires with different vertical patterns. METHODS: The study sample consisted of 60 patients (28 males, 32 females; mean age 19.8 ± 1.4 years) presenting with COS depth of at least2 mm at baseline. For each subject, lateral cephalograms and dental casts were available before treatment (T1), at the end of orthodontic therapy (T2), and 2 years after the end of treatment (T3). All subjects were divided into three groups according to vertical facial patterns. Cephalometric parameters were used to evaluate the dental movements after treatment. COS depth was measured on digital casts. Mean differences between vertical facial subgroups were contrasted by means of analysis of variance test (P < 0.01). RESULTS: In low-angle subjects, COS levelling occurred through advancement and intrusion of lower incisors, whereas in high-angle patients, the COS was flattened through extrusion and uprighting of lower posterior teeth. In the low-angle group, a significant relapse of lower incisors inclination was observed. Differently, the high-angle group exhibited a greater stability of COS obtained by stable extrusion of posterior teeth. CONCLUSIONS: The long-term instability of flared incisors determined the relapse of overbite and COS depth in the low-angle group.

Efficacy of piezocision-based flapless corticotomy in the orthodontic correction of severely crowded lower anterior teeth: a randomized controlled trial.

BACKGROUND: No randomized controlled trial (RCT) has compared flapless piezocision-assisted corticotomy in the extraction-based orthodontic decrowding of lower anterior teeth with the conventional treatment. OBJECTIVE: To evaluate the effectiveness of flapless piezocision-assisted corticotomies in accelerating lower anterior teeth alignment. TRIAL DESIGN: A parallel-group RCT was conducted. MATERIALS AND METHODS: Thirty-six patients (mean age 20.32 ± 1.96 years) in need of orthodontic treatment with a fixed orthodontic appliance were enrolled and randomly allocated to either the experimental or the control group. Following first premolar extraction, five radiographic-guided micro incisions and localized piezoelectric corticotomies were performed on the labial surfaces of the alveolar bone between the six anterior teeth in order to accelerate alignment for patients in the experimental group, whereas those in the control group received traditional orthodontic treatment. The overall alignment time (OAT) required to complete anterior alignment of the mandibular dental arch (OAT) was measured. Little's Irregularity Index (LII) was also calculated at monthly intervals. Randomization was performed using a software-generated list of random numbers; the recruited patients were divided into two parallel groups with a 1:1 allocation ratio. Assessor blinding was employed. RESULTS: One hundred and eight severe dental crowding patients were evaluated for eligibility, 40 of them fulfilled the inclusion criteria. Thirty-six participants were allocated to the treatment groups randomly. One female patient was lost to follow-up from the control group, and another female patient was excluded from analysis for the experimental group. Accordingly, the results of 34 patients were statistically analyzed. OAT was reduced by 59% in the experimental group compared to the control group, with a statistically significant difference between the two groups (P < 0.001). No harms were encountered. CONCLUSION: Flapless piezocision technique was very effective in accelerating orthodontic tooth movement. TRIAL REGISTRATION: This trial was registered at Clinical Trials.gov (Identifier: NCT02977221).

Differences in the Alignment Pattern of the Maxillary Dental Arch Following Fixed Orthodontic Treatment in Patients With Bilateral Cleft Lip and Palate: Anteroposterior-Collapsed Arch Versus Transverse-Collapsed Arch.

The purpose of this study was to investigate differences in the alignment pattern of the collapsed maxillary arch following fixed orthodontic treatment (FOT) in bilateral cleft lip and palate (BCLP) patients according to collapse type. Fifteen BCLP patients were divided into Group 1 (anteroposterior-collapsed arch, n = 7) and Group 2 (transverse-collapsed arch, n = 8) according to maxillary arch shape before FOT. Linear and angular variables of lateral cephalograms and dental models were evaluated before (T1) and after FOT (T2), and statistical analysis was performed. In cephalometric measurements at T1, both the groups exhibited retrusive maxillae, a Class III relationship, and lingual inclination of U1-SN. At T2, significant improvement of U1-SN was observed in both the groups (P < 0.01 in Group 1; P < 0.05 in Group 2). In the model measurements at T1, the inter-second premolar width (IP2W), inter-first molar width (IM1W), and left segmental angle were smaller in Group 2 than in Group 1 (IP2W, P < 0.001; IM1W, P < 0.05; LSA, P < 0.05). From T1 to T2, the arch width increased significantly in Group 2 (inter-canine width, IP1W, IP2W, and IM1W; all P < 0.05), but not in Group 1. Therefore, there were significant differences in ΔIP2W (2.4 mm versus 14.9 mm, P < 0.01) and ΔIM1W (-0.7 mm versus 5.9 mm, P < 0.001) between Groups 1 and 2. In both the groups, the molar depth and right and left segmental angles increased significantly, while the premaxillary rotation angle decreased significantly (molar depth, RSA, LSA, and PMRA; all P < 0.05). The alignment strategy for the maxillary premolar and molar areas should be modified according to arch shape in BCLP patients.

Anthropometric Analysis of the Dental Arches of Five-Year-Old Children With Cleft Lip and Palate.

This study aimed to analyze the dimensional alterations of the dental arches of 5-year-old children with cleft lip and palate and to compare these dimensions with children without oral clefts. One hundred twenty children were divided into the following groups: unilateral cleft lip (UCL), unilateral cleft lip and palate (UCLP), cleft palate (CP), and control (C). A specific software was used to digitize the dental casts and perform the anthropometric analyses through the measurement of transversal linear intercanine and intermolar distances on the maxilla and mandible. The intergroup comparisons of the maxillary dimensions exhibited that the intercanine distances of groups C and UCL were statistically greater than that of groups UCLP and CP. The intermolar distance was significantly smaller in group UCLP than in the other groups. No statistically significant difference occurred in the mandibular intercanine and intermolar distance among groups. The analysis of the superposition of the maxillary over the mandibular transversal distances showed statistically significant differences among groups. This study showed that at 5-year old, the children with cleft involving the palate had more maxillary dimensional alterations than those without cleft palate.

Active Presurgical Infant Orthopedics for Unilateral Cleft Lip and Palate: Intercenter Outcome Comparison of Latham, Modified McNeil, and Nasoalveolar Molding.

OBJECTIVE: To compare dental arch relationship, craniofacial form, and nasolabial aesthetic outcomes among cleft centers using distinct methods of presurgical infant orthopedics (PSIO). DESIGN: Retrospective cohort study. SETTING: Four cleft centers in North America. PATIENTS: One hundred ninety-one children with repaired complete unilateral cleft lip and palate (CUCLP). MAIN OUTCOME MEASURES: Dental arch relationship was assessed using the GOSLON Yardstick. Craniofacial form was assessed by 12 cephalometric measurements. Nasolabial aesthetics were assessed using the Asher-McDade system. Assessments were performed between 6 and 12 years of age. RESULTS: The center that used no PSIO achieved the most favorable dental arch relationship and maxillomandibular relationship, with a median GOSLON score of 2.3 ( P < .01) and an ANB angle of 5.1° ( P < .05). The proportion of children assigned a GOSLON score of 4 or 5, predictive of the need for orthognathic surgery in adolescence, was 16% at the center that used no PSIO and no secondary surgery, compared to 76% at the centers that used the Latham appliance and early secondary lip and nose surgery ( P < .01). The center that used no PSIO and no secondary surgery achieved significantly less favorable nasolabial aesthetic outcomes than the centers using Latham appliance or nasoalveolar molding (NAM) ( P < .01). CONCLUSIONS: Effects of active PSIO are multifaceted and intertwined with use of revision surgery. In our study, centers using either the Latham appliance combined with early revision surgery or the NAM appliance without revision surgery achieved better nasolabial aesthetic outcomes but worse maxillary growth, compared to a center using no PSIO and secondary surgery.

Clinical effectiveness of 2 orthodontic retainer wires on mandibular arch retention.

INTRODUCTION: The aim of this study was to evaluate and compare the clinical success of 2 lingual retainer wires. METHODS: The 120 patients included in the study were divided into 2 groups randomly. In group 1, 0.0175-in 6-strand stainless steel wire (Ortho Technology, Lutz, Fla) was used, the lingual retainers were fabricated on plaster models, and a silicon transfer key was used. In group 2, 0.0195-in dead-soft coaxial wire (Respond; Ormco, Orange, Calif) was used, and the lingual retainers were fabricated directly in the patient's mandibular arch without a study model. Pretreatment, posttreatment, and posttreatment 3-month, 6-month, 9-month, and 12-month 3-dimensional orthodontic models were evaluated. Failure rates, mandibular arch irregularity values, intercanine distances, and arch lengths were compared. RESULTS: The clinical bond failure rates were 13.2% for the 0.0175-in 6-strand stainless steel wire and 18.9% for the 0.0195-in dead-soft wire. The difference in bond failures between the 2 groups was not statistically significant. There was a statistically significant increase in mandibular arch irregularity in both groups during the 12-month follow-up. However, the increase was significantly higher in the second group than in the first one. Furthermore, the intercanine distance decreased over time in the second group. CONCLUSIONS: Our findings regarding mandibular arch measurements indicate that fabrication of lingual retainers can be more safely accomplished with 0.0175-in 6-strand stainless steel wire than with 0.0195-in dead-soft coaxial wire.

Effect of posterior space discrepancy and third molar angulation on anterior overbite.

INTRODUCTION: In this study, we aimed to determine the effect of maxillary and mandibular posterior space discrepancies and third molar angulations on the overbite. METHODS: Pretreatment lateral cephalograms of 131 subjects were analyzed. The sample included 83 open-bite and 48 deepbite subjects. A multiple regression analysis was used to evaluate the influence of maxillary and mandibular posterior space discrepancies and third molar angulations (predictor variables) on overbite. Correlations between posterior space discrepancy and third molar angulation, and correlations between predictor variables and dental angulation and height of posterior teeth and incisors were evaluated with the Pearson correlation coefficient. Subgroups with accentuated negative overbite and deepbite (27 open-bite, 37 deepbite) were compared with t tests. RESULTS: The multiple linear regression analysis showed a positive association of the mesial angulation of the mandibular third molar with overbite. Posterior space discrepancy was negatively associated with posterior teeth mesial angulation and dentoalveolar height. However, these associations were weak, with no clinically significant implications. The deepbite subgroup showed significantly greater mesial angulation of the mandibular third molars than did the open-bite subgroup. CONCLUSIONS: There was no clinically significant effect of posterior space discrepancies and third molar angulations on overbite and dental angulation and height of posterior teeth and incisors.

Incisor malalignment and the risk of periodontal disease progression.

INTRODUCTION: The objective of this study was to investigate the association between incisor crowding, irregularity, and periodontal disease progression in the anterior teeth. METHODS: Data collected over 35 years from men enrolled in the Veterans Affairs Dental Longitudinal Study included information concerning pocket depth and alveolar bone loss. Plaster casts of the maxillary (n = 400) and mandibular (n = 408) arches were available for baseline measurements. Periodontal disease in the anterior teeth was defined as per arch sum of pathologic pocket depth and sum of teeth with any alveolar bone loss in the anterior sextants. Incisor malalignment status was defined by the anterior tooth size-arch length discrepancy index and Little's Irregularity Index. Adjusted mixed effects linear models computed the beta (ß) estimates and 95% confidence intervals (95% CI) of the amounts of change in periodontal disease outcomes by the level of malalignment. RESULTS: In the anterior maxillary arch, crowding and spacing were significantly associated with an increased per-arch sum of pathologic pocket depth (ß, 0.70 mm; 95% CI, 0.20-1.21, and ß, 0.49 mm; 95% CI, 0.06-0.91, respectively). In the anterior mandibular arch, incisor crowding and irregularity were significantly associated with an increased per-arch sum of pathologic pocket depth (mild crowding: ß, 0.47 mm; 95% CI, 0.01-0.93; severe irregularity: ß, 0.94 mm; 95% CI, 0.50-1.38), and the sum number of teeth with alveolar bone loss (mild and moderate-to-severe crowding: ß, 0.45 teeth; 95% CI, 0.08-0.82; and ß, 0.45 teeth; 95% CI, 0.13-0.83, respectively; moderate irregularity: ß, 0.34 teeth; 95% CI, 0.06-0.62). CONCLUSIONS: Certain incisor malalignment traits (ie, maxillary incisor crowding, maxillary incisor spacing, mandibular incisor mild crowding, mandibular incisor moderate-to-severe crowding, mandibular incisor moderate irregularity, and mandibular incisor severe irregularity) are associated with significant periodontal disease progression.

Performance of Hawley-type retainers: a systematic review of randomized clinical trials.

Background: Although post-treatment changes are almost inevitable, and retention has long been recognized as one of the most critical and routine problems faced by orthodontists, there remains a lack of certainty regarding the parameters of any definitive retention protocol following orthodontic treatment. Objective: To investigate the performance of the Hawley-type retainers. Search methods: Search without restrictions in 15 databases and hand searching until December 2016. Selection criteria: Randomized clinical trials comparing the performance of Hawley-type retainers to other removable appliances or comparing different Hawley-type retainers' wearing schedules. Data collection and analysis: Following study retrieval and selection, data extraction and individual study risk of bias assessment using the Cochrane Risk of Bias Tool took place. The overall quality of the available evidence was assessed with the Grades of Recommendation, Assessment, Development, and Evaluation approach. Results: Finally, 10 studies were identified involving 854 individuals, followed for up to 1 year after debonding. Eight studies compared subjects using Hawley and clear thermoplastic retainers; another compared Hawley to positioner and, finally, one trial involved individuals allocated to different Hawley appliance wearing schedules. Three studies were considered as being of low, four of unclear, and three of high risk of bias. In general, few differences were observed between the Hawley and other removable retainers regarding outcomes relevant to maxillary and mandibular dental arch measurements, dental arch relationships and occlusal contacts, speech evaluation, patient reported outcomes, adverse effects, and problems related to the appliances, as well as economic evaluation related outcomes. Moreover, no differences were observed between the compared Hawley wearing schedules. Overall, the quality of the available evidence was considered low. Conclusions: Given the overall quality of the available evidence and the multitude of parameters, which may have affected the results of the included trials, good practice would suggest further research in the respective field in order to increase both the quantity and quality of information available. Registration: PROSPERO (CRD42015029279). Funding: No funding was received for the present systematic review.

Growing patients with Duchenne muscular dystrophy: longitudinal changes in their dentofacial morphology and orofacial functional capacities.

Aim: The aim of this study was to describe the longitudinal changes in facial morphology, dental arch alterations and oral functional capacities that occur in growing patients with Duchenne muscular dystrophy (DMD) in order to identify the effects of the progression of the disease. Subjects and Methods: Twelve DMD patients (6.5-17.5 years of age) and 12 matched controls were screened on two different occasions (T1 and T2), 2 years apart. Dental casts, lateral cephalometric radiographs, maximal posterior bite force and labial force were measured to determine changes in their functional capacities and dentofacial morphology. Furthermore, the thickness and echogenicity of the masseter muscle were measured during clenching. Statistical evaluation: Unpaired t-tests were performed to evaluate the differences between the DMD patients and their healthy matched controls; paired t-tests were used to assess the changes that occurred within each group between T1 and T2. Results: Between T1 and T2 the following changes were observed: widening of the lower dental arch for the DMD patients of 2.6mm (±0.9mm) compared to a slight reduction of -0.1mm (±0.8mm) for the control group (P = 0.001). We found a statistically significant reduction of the sagittal skeletal intermaxillary relationship (ANB-angle) of 2.0° (±2.0°) in the DMD group (P = 0.012). In T1 and T2, the maximal posterior bite force and the labial force were lower for the DMD patients compared to the control group (P = 0.001), who showed an increase during this period. Conclusion: The results indicate that DMD influences the facial morphology, dental arch dimensions and oral functional capacities. The longitudinal perspective of this study revealed that the worsening of most of the measured parameters is associated with the progression of the disease. Besides the expected deterioration of the functional measurements, we found in all patients, a marked transverse increase of the posterior part of the dental arches, more in the lower than in the upper, resulting in posterior crossbites, as well as a tendency towards a skeletal Class III relationship.

Does headgear treatment in young children affect the maxillary canine eruption path?

Objective: To test whether early headgear (HG) treatment and space conditions in the dental arch affect the eruption pathway of the maxillary canines in young children with mixed dentition. Subjects and methods: Data from two randomized controlled trials studying the effects of early HG treatment were pooled, yielding a study sample comprising 99 children (38 girls and 61 boys, mean age 7.6 years) with Angle Class II occlusion. Fifty-one children were treated with HG and 48 children served as an untreated control group (CG). Digital 3D models and panoramic radiographs were taken before (T0) and after (T1) treatment, and changes in the maxillary canine eruption angle and interdental spaces were measured at T0 and T1. A paired samples t-test was used to assess changes in maxillary canine angulation, and an independent samples t-test was used to evaluate the effect of HG treatment on spacing in the dental arch. Associations between intra-arch space conditions and changes in maxillary canine angulation were estimated with linear regression models. Results: The eruption pattern of the permanent canine was significantly more vertical in the HG group than in the CG. The linear regression models showed a statistically significant association among the intercanine distance, crowding in the anterior part of the maxilla, and changes in the maxillary canine eruption angle. The maxillary canine eruption pattern changed significantly more to a vertical direction in spaced dental arches than in crowded dental arches in the HG group. Conclusion: This study shows that early HG treatment in children with Angle Class II occlusion may change the eruption pattern of permanent maxillary canines to a more vertical direction. This change appears to be related to space conditions in the maxillary arch, especially in the intercanine region, with more effect in children with spaced dental arches than in children with crowded dental arches.

Association between 3D palatal morphology and upper arch dimensions in buccally displaced maxillary canines early in mixed dentition.

Objectives: To evaluate the association between maxillary dental arch transverse dimensions, palatal depths, palatal area and volume with buccally displaced canine (BDC) in mixed dentition subjects when compared to non-BDC subjects using laser scanner 3D technology. Materials and methods: Sixty Caucasian subjects, 8-11 years of age (mean, 9.26 ± 1.48 years), were included. In each group (BDC and non-BDC) 30 children were matched. Digital dental casts were obtained using a 3 Shape D700 laser scanner. Intercanine and intermolar widths (cusp and gingival levels), anterior and posterior palatal depth (cusp level), palatal surface area and volume were measured. An independent sample Student's t-test and an ANOVA were undertaken with significance level set as P < 0.05. Results: Intercanine widths at the cusp (1.76 mm; P = 0.020) and the gingival level (1.6 mm; P = 0.006), palatal area (133 mm2; P = 0.021) and volume (790 mm3; P = 0.046) were significantly lower in the BDC compared to the control group. Limitations: A smaller part of the subjects was in late mixed dentition phase. To overcome this limitation a matched control group was used. Some subjects did not have some teeth because of the transition phase which might have had an influence on the dental measurements. However, these subjects were not excluded to avoid introducing a bias. Conclusions: 3D evaluation of the maxillary arch and palate highlighted significant differences between BDC and non-BDC mixed dentition subjects. Maxillary dental arch dimensions and palate morphology may allow early identification and prevention of maxillary canine impaction.

Use of Interarch Width Ratio to measure Transverse Relationship: A New Method to measure and assess Interarch Discrepancy.

AIM: The purpose of this study was to assess the arch width, transverse discrepancy, and transverse interarch ratio for class I malocclusion sample, with and without crossbite, in permanent dentition stage. MATERIALS AND METHODS: Records of class I malocclusion patients with minimal crowding and spacing with and without posterior crossbite were selected. Each group consisted of 40 pairs of dental casts (20 males and 20 females). Arch widths were measured for the canine, first, and second premolars, and first permanent molars using the buccal approach. Means and standard deviations (SDs) of dental arch widths were measured for the maxillary and mandibular arches, and the interarch width ratio was calculated. RESULTS: There was a highly significant difference between the noncrossbite and crossbite groups regarding the maxillary width, p < 0.001. However, no differences were found between groups for the mandibular widths, p > 0.01. There were also significant differences between both groups for the intercanine, first and second premolars, and first molar ratios, p < 0.001. CONCLUSION: This new simple method showed that a transverse maxillary-mandibular ratio of 1:1.1 is ideal. A ratio less than 1:0.9 will indicate the presence of crossbite. CLINICAL SIGNIFICANCE: The interarch ratio significantly aids in orthodontic treatment planning in patients requiring maxillary expansion and/or surgical cases.