A comparative assessment of failures and periodontal health between 2 mandibular lingual retainers in orthodontic patients. A 2-year follow-up, single practice-based randomized trial.

INTRODUCTION The objective of this study was to compare the survival rates and periodontal health in patients with 3-strand round twisted (RT) vs 8-strand rectangular braided (RB) fixed retainers bonded to all 6 anterior teeth in the mandible. METHODS A total of 133 patients completing orthodontic treatment (median age, 24.6 years; 25th percentile, 17.2 years; 75th percentile, 32.4 years; minimum, 15.1 years; maximum, 49.8 years) were randomly allocated in a 1:1 ratio to receive either an RT or RB wire retainer. Inclusion criteria were all mandibular permanent incisors and canines present, no active caries, no restorations, no fractures on the mandibular incisors and canines, no periodontal disease. Patients with poor oral hygiene before debonding were excluded from the trial. The primary outcome was any first-time retainer failure. Secondary outcomes were periodontal index, bleeding on probing, plaque index, gingival index, and probing depth. Randomization was accomplished with random permuted blocks of size 4, 6, or 8 with allocation concealed in sequentially numbered, opaque, sealed envelopes. Blinding was not possible in this trial. Patients were evaluated at baseline, 3, 6, 12, 18, and 24 months after placement of the retainer. Retainer survival was assessed using Cox regression. Periodontal parameters were reported at each time point and generalised estimating equations were used to assess the effect of treatment, time, tooth and treatment X time interaction on the indices. RESULTS Baseline characteristics were similar between groups; in 1 patient, the intervention was discontinued. During 2-year follow-up 37 of 66 (56.1%, RT group) and 32 of 66 (48.5%, RB group) retainers failed at least once (log-rank test, P = 0.55). The adjusted hazard ratio was 0.69 (95% confidence interval, 0.42-1.12; P = 0.13). Neither age nor gender was a predictor of failure. All periodontal parameters (periodontal index, bleeding on probing, plaque index, gingival index, and pocket depth) were comparable between groups and remained relatively stable during follow-up. CONCLUSIONS The overall risk for first-time failure was high and amounted to 52.3% (56.1% in the RT group and 48.5% in the RB group). There was no difference in terms of survival or periodontal health between the examined retainers

Gingival labial recessions and the post-treatment proclination of mandibular incisors

SummaryIntroduction: A prerequisite for development of gingival recession is the presence of alveolar bone dehiscence. Proclination of mandibular incisors can result in thinning of the alveolus and dehiscence formation. Objective: To assess an association between proclination of mandibular incisor and development of gingival recession. Methods: One hundred and seventeen subjects who met the following inclusion criteria were selected: 1. age 11-14 years at start of orthodontic treatment (TS), 2. bonded retainer placed immediately after treatment (T0), 3. dental casts and lateral cephalograms available pre-treatment (TS), post-treatment (T0), and 5 years post-treatment (T5), and 4. post-treatment (T0) lower incisor inclination (Inc_Incl) 100.5°. Two groups were formed: non-proclined (N = 57; mean Inc_Incl = 90.8°) and proclined (N = 60; mean Inc_Incl = 105.2°). Clinical crown heights of mandibular incisors and the presence of gingival recession sites in this region were assessed on plaster models. Fisher's exact tests, t-tests, and regression models were computed for analysis of inter-group differences. Results: The mean increase of clinical crown heights (from T0 to T5) of mandibular incisors ranged from 0.75 to 0.83mm in the non-proclined and proclined groups, respectively (P = 0.273). At T5, gingival recession sites were present in 12.3% and 11.7% patients from the non-proclined and proclined groups, respectively. The difference was also not significant (P = 0.851). Conclusions: The proclination of mandibular incisors did not increase a risk of development of gingival recession during five-year observation in comparison non-proclined teet

Gingival recessions and the change of inclination of mandibular incisors during orthodontic treatment

SUMMARY A recent systematic review demonstrated that, overall, orthodontic treatment might result in a small worsening of periodontal status. The aim of this retrospective study was to test the hypothesis that a change of mandibular incisor inclination promotes development of labial gingival recessions. One hundred and seventy-nine subjects who met the following inclusion criteria were selected: age 11-14 years at start of orthodontic treatment (TS), bonded retainer placed immediately after treatment (T0), dental casts and lateral cephalograms available pre-treatment (TS), post-treatment (T0), 2 years post-treatment (T2), and 5 years post-treatment (T5). Depending on the change of lower incisor inclination during treatment (ΔInc_Incl), the sample was divided into three groups: Retro (N = 34; ΔInc_Incl ≤ -1 degree), Stable (N = 22; ΔInc_Incl > -1 degree and ≤1 degree), and Pro (N = 123; ΔInc_Incl > 1 degree). Clinical crown heights of mandibular incisors and the presence of gingival recessions in this region were assessed on plaster models. Fisher's exact tests, one-way analysis of variance, and regression models were used for analysis of inter-group differences. The mean increase of clinical crown heights (T0 to T5) of mandibular incisors ranged from 0.6 to 0.91 mm in the Retro, Stable, and Pro groups, respectively; the difference was not significant (P = 0.534). At T5, gingival recessions were present in 8.8, 4.5, and 16.3 per cent patients from the Retro, Stable, and Pro groups, respectively. The difference was not significant (P = 0.265). The change of lower incisors inclination during treatment did not affect development of labial gingival recessions in this patient grou

Morphological variability in unrepaired bilateral clefts with and without cleft palate evaluated with geometric morphometrics

In subjects with orofacial clefts, there is an unresolved controversy on the effect of congenital maxillary growth deficiency vs. the effect of surgical intervention on the outcome of treatment. Intrinsic growth impairment in subjects with orofacial clefts can be studied by comparing facial morphology of subjects with untreated cleft and unaffected individuals of the same ethnic background. Bilateral cleft lip and palate is the most severe and least prevalent form of the orofacial cleft. The aim of this study was to compare facial morphology in subjects with unrepaired complete bilateral clefts and unaffected controls using geometric morphometrics. Lateral cephalograms of 39 Indonesian subjects with unrepaired bilateral complete cleft lip and alveolus (mean age: 24 years), or unrepaired bilateral complete cleft lip, alveolus, and palate (mean age: 20.6 years) and 50 age and ethnically matched controls without a cleft (25 males, 25 females, mean age: 21.2 years) were digitized and traced and shape variability was explored using principal component analysis, while differences between groups and genders were evaluated with canonical variate analysis. Individuals with clefts had a more pronounced premaxilla than controls. Principal component analysis showed that facial variation in subjects with clefts occurred in the anteroposterior direction, whereas in controls it was mostly in the vertical direction. Regression analysis with group, sex, and age as covariates and principal components from 1 to 6 as dependent variables demonstrated a very limited effect of the covariates on the facial shape variability (only 11.6% of the variability was explained by the model). Differences between cleft and non-cleft subjects in the direction of facial variability suggest that individuals with bilateral clefts can have an intrinsic growth impairment affecting facial morphology later in life.</p

Regional facial asymmetries in unilateral orofacial clefts

SummaryObjectives: Assess facial asymmetry in subjects with unilateral cleft lip (UCL), unilateral cleft lip and alveolus (UCLA), and unilateral cleft lip, alveolus, and palate (UCLP), and to evaluate which area of the face is most asymmetrical. Methods: Standardized three-dimensional facial images of 58 patients (9 UCL, 21 UCLA, and 28 UCLP; age range: 8.6-12.3 years) and 121 controls (age range 9-12 years) were mirrored and distance maps were created. Absolute mean asymmetry values were calculated for the whole face, cheek, nose, lips, and chin. One-way analysis of variance, Kruskal-Wallis, and t-test were used to assess the differences between clefts and controls for the whole face and separate areas. Results: Clefts and controls differ significantly for the whole face as well as in all areas. Asymmetry is distributed differently over the face for all groups. In UCLA, the nose was significantly more asymmetric compared with chin and cheek (P = 0.038 and 0.024, respectively). For UCL, significant differences in asymmetry between nose and chin and chin and cheek were present (P = 0.038 and 0.046, respectively). In the control group, the chin was the most asymmetric area compared to lip and nose (P = 0.002 and P = 0.001, respectively) followed by the nose (P = 0.004). In UCLP, the nose, followed by the lips, was the most asymmetric area compared to chin, cheek (P < 0.001 and P = 0.016, respectively). Limitations: Despite division into regional areas, the method may still exclude or underrate smaller local areas in the face, which are better visualized in a facial colour coded distance map than quantified by distance numbers. The UCL subsample is small. Conclusion: Each type of cleft has its own distinct asymmetry pattern. Children with unilateral clefts show more facial asymmetry than children without cleft

A brief history of orthodontic retention.

The retention phase has become an accepted part of orthodontic therapy. Irrespective of the patient's age, underlying malocclusion or the type of mechanotherapy, an orthodontist will use some retention method in virtually every patient following completion of the active treatment. This article presents a short description of the history of orthodontic retention and highlights major developments in retention strategy

A brief history of orthodontic retention

The retention phase has become an accepted part of orthodontic therapy. Irrespective of the patient's age, underlying malocclusion or the type of mechanotherapy, an orthodontist will use some retention method in virtually every patient following completion of the active treatment. This article presents a short description of the history of orthodontic retention and highlights major developments in retention strategy

The cervical vertebrae maturation (CVM) method cannot predict craniofacial growth in girls with Class II malocclusion

Summary Introduction: The cervical vertebrae maturation (CVM) method is used to determine the timing of treatment of Class II malocclusion. Because its performance has not been tested in patients with Class II, the objective of this study was to evaluate the effectiveness of the CVM method in predicting growth peak in Class II malocclusion. Methods: Twenty-nine untreated girls with Class II malocclusion were identified among participants of the Nijmegen Growth Study. Each girl had a series of cephalograms taken semi-annually from 9 to 14 years of age. The CVM status was established by five observers on a cephalogram taken at 9 years; mandibular and maxillary length and anterior face height were assessed on all available cephalograms. Method error was evaluated with kappa statistics and Bland-Altman (BA) plots. Regression analysis was used to determine if CVM grade can predict the phase of maximum facial growth. Results: The mean kappa for intra-rater agreement during grading with CVM was 0.36 (fair agreement). BA plots demonstrated acceptable agreement for cephalometric measurements. The regression analysis demonstrated that the only chronologic age was associated with the facial growth. The largest effect of age was for condylion-gnathion (Cd-Gn) and articulare-gnathion (ArGn)-for every additional 6 months the Cd-Gn increases by 1.8 mm [95 per cent confidence interval (CI): 1.7, 1.9, P &lt; 0.001] and Ar-Gn increases by 1.59 mm (95 per cent CI: 1.52, 1.67, P &lt; 0.001). The CVM grade could not predict the change of cephalometric variables. Conclusions: There is no evidence to support the hypothesis that the CVM method can predict the peak of craniofacial growth

Long-term Effectiveness of Maxillary and Mandibular Bonded Orthodontic Retainers.

PURPOSE This retrospective cohort study investigated the long-term effectiveness of one type of maxillary and 2 types of mandibular fixed lingual retainers. MATERIALS AND METHODS Eighty orthodontic patients in retention for 10-15 years were included. Irregularity index, intercanine width, overjet (OJ) and overbite (OB) were measured on plaster models at 3 occasions: (T1) pre-treatment, (T2) post-treatment and (T3) 10-15 years post-treatment. Analyses assessed the effect of the retainer type and time on mandibular irregularity, intercanine width and retainer failure. RESULTS In the mandible, the irregularity index increased (0.43 mm) between T2 and T3 for the 0.027" β-titanium (TMA) retainers bonded to canines only while it was stable (-0.02 mm) for the 0.016" x 0.022" braided stainless steel retainers (SS6) bonded to all six anterior teeth. The intercanine width was relatively stable in both groups during the entire observation period. In the maxilla, the irregularity index was stable between T2 and T3 (+0.07 mm). The intercanine width increased (+2.02 mm) during treatment T1-T2 and was stable (-0.02 mm) in the retention phase T2 to T3. CONCLUSIONS In the mandible, SS6 retainers were slightly more effective in maintaining alignment compared to the TMA retainers. In the maxilla, the SS4 retainers without canine extensions were effective in maintaining alignment. All retainers were effective in maintaining the intercanine width