Postretention relapse of mandibular anterior crowding in patients treated without mandibular premolar extraction

Long-term relapse of anterior teeth in orthodontic patients treated with and without premolar extractions using a 3-dimensional surface mesh analysis

INTRODUCTION

The study evaluated the long-term postretention changes in patients with borderline crowding treated with and without premolar extractions using 3-dimensional surface registration analyses and 2-dimensional (2D) conventional measurements.

METHODS

The study sample comprised 29 nonextraction patients (nonextraction group [NG]) and 33 extractions (extraction group [EG]). Cephalometric radiographs and dental models of the included patients were used from pretreatment, posttreatment, and postretention. Retention durations were 3.76 ± 1.26 years and 4.52 ± 1.94 years in the NG and EG, respectively. The postretention follow-up period was 17.06 ± 5.83 years for the EG and 14.30 ± 5.70 years for the NG, with similar long-term observations. Maxillary and mandibular superimpositions were performed using 3-dimensional digital scans of the dental models and commercial software. In addition, conventional 2D model measurements and the irregularity index were also assessed.

RESULTS

The investigated parameters regarding the surface changes showed nonsignificant differences (P >0.05) between the 2 groups in the maxillary and mandibular anterior 6 teeth, except for the under tolerance value (the percentage of mesh points that is less than the lower tolerance limit) in mandibular surface registrations (P <0.044). In both groups, the maxillary and mandibular irregularity index and maxillary and mandibular intercanine distances showed significant relapses (P <0.05).

CONCLUSIONS

Comparable surface change outcomes were observed in the NGs and EGs. However, the percentage of meshes exceeding the negative threshold value (-1 mm) of the mandibular dentition in the NG exceeded the EG, indicating more significant lingual movement and relapse of the incisors. In addition, the 2D conventional linear relapse measurements were well below the 3.5 mm threshold value reported in the literature. This finding indicated that both treatment approaches provide acceptable long-term stability in borderline patients when similar retention regimens are employed.

Impact of Vitamin D3 on Postorthodontic Treatment Stability: A Randomized Controlled Trial

AIM

This study aims to clinically evaluate whether the local administration of vitamin D3 enhances postorthodontic tooth stability over a period of 3 months immediately after debonding.

MATERIALS AND METHODS

Patients aged 15-30 years with dental malocclusion and moderate crowding in the lower arch (Little's irregularity score of 4-6) were selected and randomly split into the experimental and the control groups. After complete alignment and leveling, vitamin D3 injection was delivered to the experimental group and the control group was given a placebo injection with 0.9% normal saline mixed with 2% lignocaine. Fourteen days after the injection, the lower archwires were removed from the control and experimental groups.

RESULTS

Relapse was significantly higher in control than in the experimental group at all-time intervals. Statistically significant values of relapse were observed at T2 and T3 intervals between the two groups, with greater relapse in the control group than in the experimental group. Inter-canine width, arch perimeter, and intermolar width showed mild changes over 3-month period, but there were no significant differences between the two groups.

CONCLUSION

Relapse was seen in both the control and the experimental in the first 4 weeks of the study. Still, the control group showed a greater relapse rate in the following 8th week and 12th week when compared to the experimental group. How to cite this article: Kothandaraman T, Anbarasu P, Dinesh SPS, et al. Impact of Vitamin D3 on Postorthodontic Treatment Stability: A Randomized Controlled Trial. J Contemp Dent Pract 2024;25(12):1156-1161.

Long-term stability of mandibular incisor alignment in patients treated nonextraction with or without interproximal enamel reduction

INTRODUCTION

This study aimed to compare long-term mandibular incisor stability in nongrowing patients with moderate crowding treated nonextraction with and without interproximal enamel reduction (IPR).

METHODS

Forty-two nongrowing patients with Class I dental and skeletal malocclusion with moderate crowding were divided into 2 groups with an equal number of patients depending on whether IPR was used (IPR group) or not (non-IPR group) during treatment. All patients were treated by the same practitioner and used thermoplastic retainers full-time for 12 ± 1 months at the end of the active treatment. Changes in Peer Assessment Rating scores, Little's irregularity index (LII), intercanine width (ICW), and mandibular incisor inclination (IMPA and L1-NB°) were evaluated using pretreatment, posttreatment, and 8 ± 1 years postretention dental models and lateral cephalograms.

RESULTS

At the end of the treatment, Peer Assessment Rating scores and LII decreased, and ICW, IMPA, and L1-NB° increased significantly (P <0.001) in both groups. At the end of the postretention period, in both groups, LII increased, and ICW decreased significantly (P <0.001) compared with posttreatment values, whereas IMPA and L1-NB remained stable. When treatment changes were compared, increases in ICW, IMPA, and L1-NB were significantly (P <0.001) higher in the non-IPR group. When postretention changes were compared, the only significant difference between 2 groups was observed in ICW. The decrease in ICW was significantly higher in the non-IPR group.

CONCLUSIONS

Long-term stability of mandibular incisor alignment in Class I nongrowing patients with moderate crowding treated nonextraction with and without IPR was similar.

The Effect of Third Molars on the Mandibular Anterior Crowding Relapse-A Systematic Review

The present systematic review updates the evidence on wisdom teeth contributing to lower incisor crowding following orthodontic treatment. Relevant literature was searched on online databases, namely Pubmed, Scopus, and Web of Science, up to December 2022. Eligibility criteria were formulated using the PICOS approach and PRISMA guidelines. Eligible research included original clinical studies involving patients previously being treated orthodontically with permanent dentition at the end of treatment, regardless of sex or age. The initial search yielded 605 citations. After considering eligibility criteria and removing duplicates, only 10 articles met the criteria for inclusion. The risk of bias of eligible studies was evaluated using the Cochrane Handbook for Systematic Reviews and Interventions tool. The majority were highly biased, mainly regarding allocation concealment, group similarity, and assessment blinding. The vast majority did not report statistically significant associations between the presence of third molars and crowding relapse. However, a minor effect has been suggested. Seemingly, there is no clear connection between mandibular third molars and incisor crowding after orthodontic treatment. The present review did not find adequate evidence to advocate preventative removal of the third molars for reasons of occlusal stability.

Association between arch width changes and long-term stability 20 years after orthodontic treatment with and without extractions

OBJECTIVES

To investigate long-term stability 20 years after orthodontic treatment and the association with arch width changes during treatment.

MATERIALS AND METHODS

This retrospective study investigated 103 patients with Class I and II malocclusions treated with fixed appliances with and without extractions. The sample was treated by one experienced orthodontist and collected from a private orthodontic office. Dental casts were obtained pretreatment (T1), posttreatment (T2), and long-term postretention (T3); they were scanned and converted to STL files. Measurements were evaluated in for the upper and lower arch: intercanine width (IC), intermolar (IM) width, Little's irregularity index (LII).

RESULTS

There were 73 female and 30 male patients. Class I was present in 74 patients and Class II in 29. Average postretention time was 17.2 (±6.5) years after an average active retention time of 3.4 (±1.17) years. Extraction was performed in 55 patients while 48 received nonextraction treatment. Bonferroni Post Hoc test showed that LII in the upper and lower arches at T1 was significantly higher in the extraction group (P < .001). Upper and lower arch LII at T3 was slightly higher in extraction cases but remained under 2.05 mm. LII at T3 in the upper and lower arches showed negative correlation with IM T3 in the upper arch (Pearson, N = 103, P = .047), while IC in the upper and lower arches at T3 correlated with IM T3 in the upper and lower (N = 103, P < .001).

CONCLUSIONS

Clinically relevant long-term stability in both arches was found in extraction and nonextraction cases. Intermolar width and its change during orthodontic treatment was an influential factor on long-term stability in extraction cases.

Incisor irregularity and dental arch dimensions changes in subjects with different severity of anterior crowding: a 37-year follow-up

BACKGROUND

Occlusal stability is one of the goals of orthodontic treatment, and keeping teeth aligned in the long term is a challenge for the orthodontist. This study aimed to compare the long-term incisors irregularity and dental arches dimensions changes in subjects treated with 4 premolar extractions with different pretreatment Little's irregularity index (LII). The knowledge of long-term outcomes is evidence-based information for the prognosis of future treatments.

METHODS

In total, 41 treated subjects were divided into two groups according to mandibular Little irregularity value at pretreatment (mild or severe). The maxillary and mandibular LII, transversal, and longitudinal widths were assessed at pretreatment, posttreatment, and 37-year posttreatment. Chi-square and independent t tests were used for intergroup comparison.

RESULTS

The groups presented similar behavior for all stages of maxillary and mandibular arch dimensions changes. Maxillary irregularity was corrected in both groups after treatment, and the alignment was acceptable in the long term. In the mild group, the mandibular incisor irregularity returned to pretreatment values in the long term. The mandibular LII increased in the severe group but did not return to pretreatment values in the long term.

CONCLUSIONS

The mild crowding group presented proportionally more relapse of mandibular incisor irregularity than the severe crowding group in the long term. Even so, the correction of mild and severe crowding with the extraction of 4 premolars showed satisfactory results in the long term, even with the presence of maturational changes and relapse.

Outcomes and Stability of Anterior Open Bite Treatment with Skeletal Anchorage in Non-Growing Patients and Adults Compared to the Results of Orthognathic Surgery Procedures: A Systematic Review

The objective of this review is to evaluate, on the basis of the available literature, if anterior open bite (AOB) can be successfully treated with the intrusion of molar teeth using skeletal anchorage in non-growing patients and adults and if this treatment modality provides comparable results to those obtained by orthognathic surgery procedures.

METHODS

A systematic review of published data in major databases from 2000 to 2021 was performed.

RESULTS

In total, 92 articles were included in title and abstract screening, and only 16 articles (11 concerning AOB correction by molar intrusion with skeletal anchorage, and five considering AOB treatment by orthognathic surgical intervention) qualified for thorough data extraction and analysis.

CONCLUSIONS

On the basis of this review, it seems to be possible to obtain successful results for AOB treatment in non-growing patients and adults by means of the intrusion of molar teeth with skeletal anchorage. However, due to the different methods of assessing treatment outcomes used by different authors, it is not possible to state conclusively whether the treatment of AOB by means of molar intrusion with skeletal anchorage provides long-term results that are comparable to orthognathic surgery procedures.

Occlusal changes in orthodontically treated subjects 40 years after treatment and comparison with untreated control subjects

INTRODUCTION

The objective of this study was to compare the aging changes of the dental arches in orthodontically treated and untreated subjects after a 4-decade follow-up period.

METHODS

This retrospective study analyzed 2 groups. The treated group comprised 29 patients (11 male, 18 female) presenting with Class I or Class II malocclusions orthodontically treated with extractions of 4 first premolars. Dental models taken at pretreatment (12.84 years), posttreatment (14.95 years), and long-term posttreatment (51.37 years) were evaluated. The untreated (control) group consisted of 22 untreated patients with dental models taken at 13.32, 17.82, and 60.95 years of age. The dental models were digitized, and the following variables were evaluated: Little irregularity index, intercanine, interpremolar and intermolar widths, arch length, arch perimeter, overjet, and overbite. Interphase comparison of the treated group was performed with repeated measures analysis of variance and Tukey tests. Intergroup comparisons were performed using t tests (P <0.05).

RESULTS

Crowding was corrected with treatment but relapsed significantly in the long term. Intercanine width increased with treatment and decreased in the long term. Interpremolar and intermolar widths, arch perimeter, and length decreased with treatment and continued to decrease long-term posttreatment. Overjet and overbite were corrected with treatment and remained stable in the long term. From posttreatment to long-term posttreatment, a greater crowding increase was observed in the treated group than in the untreated group. The treated group demonstrated a greater decrease in mandibular intercanine and maxillary and mandibular interpremolar widths than the untreated sample. Overbite increased in the treated group and decreased in the untreated group. The multiple regression analysis showed that previous 4-premolar extractions orthodontic treatment is significantly associated with anterior crowding in the long term.

CONCLUSIONS

In the long-term, the treated patients showed relapse of crowding and a decrease in arch form. Long-term changes of treated patients were different from untreated subjects. Relapse might have contributed to greater changes in incisor crowding and arch widths observed in the treated patients.

Association between incisor positions and amount of interdental stripping in patients undergoing orthodontic treatment

INTRODUCTION

The study aimed to investigate the effect of a nonextraction treatment approach with interdental stripping (IDS) on the dentofacial structures in patients with dental and skeletal Class I, II, and III malocclusions.

METHODS

A total of 60 patients with mild-to-moderate crowding of the teeth and nonsevere skeletal malocclusion were included and divided into 3 groups: Class I, Class II, and Class III groups (n = 20 per group). In all patients, nonextraction orthodontic treatment was administered, and those who underwent IDS at the jaw quadrants as needed were evaluated. For pretreatment and posttreatment evaluation, lateral cephalometric radiography and 3-dimensional dental model scans were acquired for each patient. For statistical analysis, paired-samples t test and 1-way analysis of variance with Tukey post-hoc test were used for parametric variables, whereas the Wilcoxon paired signed rank test and Kruskal-Wallis test with Dunn post-hoc test were used for nonparametric variables.

RESULTS

An increase in the maxillary incisor angle was observed in patients with Class I and Class III malocclusions, whereas a decrease was observed in patients with a Class II malocclusion (P < 0.05). Mandibular incisor angles were significantly increased in the Class II malocclusion group (P < 0.05) but unchanged in the other groups. IDS was more frequently applied to the posterior aspect of the maxilla and mandible in patients with a Class II malocclusion than in patients with other malocclusion types, and the amount of IDS at the anterior aspect of the mandible was significantly higher in the Class III group.

CONCLUSIONS

Combined nonextraction orthodontic treatment and IDS yielded successful treatment outcomes. IDS application was localized to different jaw regions according to the different malocclusion types.

In vitro comparison of the torsional load transfer of various commercially available stainless-steel wires used for fixed retainers in orthodontics

OBJECTIVE

To assess the torsional load transfer of various commercially available stainless-steel wires used for fixed retainers.

DESIGN

An in vitro study using a robotic device.

SETTING

Department of Pediatric Oral Health and Orthodontics, University of Basel.

METHODS

A 10° proclination of a maxillary lateral incisor of a 2-2 retainer was simulated with a robotic device. Eight stainless-steel wires with different shapes (round or rectangular), types (plain, braided, coaxial or chain) and dimensions were selected to measure the torsional load transfer at the adjacent central incisor. The influence of annealing was also tested.

RESULTS

The 0.016 × 0.016 and Bond-A-Braid™ wires (0.02645 × 0.01055-inch, 8-stranded, braided) showed the largest relative torsional load transfer (3.7% and 3.3%, respectively). The two multistranded wires - Triple Flex™ and Respond® - showed the smallest values of 1.0% and 0.7%, respectively. The spiral direction of these two multistranded wires affected the load transfer, the twisting showing larger torsional load transfer than the untwisting one.

CONCLUSION

The effective torsional load transfer depends on the dimension, shape and type of a wire. Plain and braided retainers were more predictable in torsional load transfer than multistranded retainers, which may have stored more energy in the area between the composite bonding sites. This may explain the unexpected complications reported in multistranded retainers.

Anterior tooth alignment and arch dimensions changes: 37-year follow-up in patients treated with and without premolar extraction

INTRODUCTION

The objective of this research was to evaluate the anterior tooth alignment and dental arch dimension changes after orthodontic treatments with and without premolar extractions in the long-term.

METHODS

Fifty-seven patients with Class I and Class II malocclusion were divided into 2 groups. Group 1 included 16 patients treated with nonextraction therapy, with mean initial (T1), final (T2), and long-term follow-up (T3) ages of 13.20 years, 15.07 years, and 50.32 years, respectively. The mean treatment (T2 - T1) and long-term follow-up (T3 - T2) times were 1.86 years and 35.25 years, respectively. Group 2 included 41 patients treated with extraction of 4 first premolars, with T1, T2, and T3 ages of 13.31 years, 15.63 years, and 53.60 years, respectively. The mean treatment and long-term follow-up times were 2.32 years and 37.96 years, respectively. The mean retention time was 2.26 years for both groups. The dental casts were obtained and digitized at T1, T2, and T3 stages. The following measurements were obtained: Little irregularity index, arch length, perimeter, and intercanine, interpremolar, and intermolar widths. Intragroup and intergroup comparisons were performed with repeated measures analysis of variance and t tests, respectively.

RESULTS

Anterior tooth irregularity index increased at T3 in both groups. In addition, all arch dimensions, except the intercanine width, were significantly smaller in the extraction group at T3. Both groups showed similar arch dimension changes at T3, except for the mandibular arch perimeter. The percentage of mandibular anterior tooth alignment change was significantly greater in the nonextraction than in the extraction group.

CONCLUSIONS

There was no difference in the changes of anterior alignment and transverse arch dimensions in patients treated with and without premolar extraction at T3, but the percentage of mandibular anterior tooth alignment changes was higher in the nonextraction than in the extraction patients at T3. The mandibular arch perimeter showed more of a decrease at T3 in extraction patients.

Long-Term Outcomes of Nonextraction Treatment in a Patient with Severe Mandibular Crowding

OBJECTIVE

To describe a clinical case with a severe mandibular crowding treated without extraction and showing a long-term outcome.

METHODS

A 14-year-old boy in permanent dentition showed a class I molar and cuspid relationship, a severe deep bite of 8 mm, a constricted V-shaped upper arch with moderate crowding, and a severe crowding of about 12 mm in the lower arch. The panoramic X-ray showed an impacted upper right canine. The treatment started with the placement of a transpalatal bar and 0.022 × 0.028 in standard edgewise appliances in the upper arch and a lip bumper bonded on the second lower molars. Initial leveling of the teeth was accomplished with light Australian round wires. Finishing was then performed with rectangular wires. The phase with fixed appliances lasted 2 years and 9 months, and the patient was motivated and cooperative throughout the treatment, although with poor oral hygiene. The patient was treated without extractions.

RESULTS

The space was gained with the first and second upper molar derotations using the transpalatal bar and the gingival lip bumper in the lower arch. The upper right canine was well positioned, and the maxillary arch form was improved. The severe lower crowding was completely corrected, and a good overbite was achieved.

CONCLUSION

A conservative, nonextraction treatment approach for this patient with class I malocclusion with severe mandibular crowding was effective, and the results have remained stable after a long-term follow-up (10 years).

Evaluation of conformity of preformed orthodontic archwires and dental arch form

Introduction:

The alterations in the arch form during treatment are dictated by the dimensions of the archwires.

Objective:

This study aimed to determine the mean arch dimensions of a sample of Pakistani subjects and to evaluate the conformity of preformed archwires with mandibular arch form.

Methods:

The dental records of 1,500 adult subjects were evaluated. The mandibular casts of 42 subjects (males = females = 21) with balanced facial profile, Class I occlusion, ideal overjet and overbite were included. Brackets were bonded on all teeth. Arch dimensions were evaluated at canines, first premolars, second premolars, first and second molars, with digital vernier calipers. The arch widths at the level of aforementioned teeth were evaluated on the digitized archwires, using the mean arch depths of the subjects.

Results:

In males, the archwires were found to be wider at canines and premolars, and significantly narrower at first (p< 0.001, 95% CI = 2.03 - 5.74) and second molars (p< 0.001, 95% CI = 2.29 - 7.73) as compared to the arch dimensions of the mandibular casts. In females, the archwires were significantly narrower at canines (p< 0.001, 95% CI = 1.4 - 3.97), and first (p= 0.02, 95% CI = 0.402 - 4.41) and second molars (p< 0.001, 95% CI = 1.76 - 6.13).

Conclusion:

No single commercially available archwires evaluated in the present study conformed to the arch dimensions of our subjects. Utilization of the currently available archwires may result in unwarranted modification of arch form, which may lead to unstable post-treatment teeth position.

Mandibular alignment changes after full-fixed orthodontic treatment: a systematic review and meta-analysis

Background

Although post-treatment mandibular alignment has been extensively investigated, the findings remain controversial.

Objectives

The objective was to assess mandibular alignment changes, as measured by the irregularity index, of patients who underwent full-fixed orthodontic treatment and were followed up at least 1 year after retention.

Search methods

MEDLINE, EMBASE, and Cochrane library, in addition, the reference lists of included studies, were screened. The search was conducted up to April 2018.

Selection criteria

The study designs included both interventional and observational studies of orthodontic patients who received either extraction or non-extraction treatment.

Data collection and analysis

The interventional studies were assessed using the Cochrane Collaboration’s risk of bias assessment tool. The quality of the observational studies was evaluated using National Institution of Health quality assessment tools. The first two authors independently applied the eligibility criteria, extracted the data, and assessed the risk of bias. Any conflicts were resolved with consensus discussion with the third author.

Results

The search retrieved 11 326 articles, 170 of which were assessed for eligibility. There were 44 studies included in the qualitative assessments and 30 in the meta-analyses. The studies included 1 randomized control trial (RCT) and 43 observational studies. The RCT was judged to have a high risk of bias and all of the observational studies had either fair or poor quality. The meta-analysis was based on studies judged to be of fair quality, including a total of 1859 patients. All meta-analyses were performed using random-effect models. The standardized mean difference between post-treatment and post-retention irregularity was 1.22 (95% CI, 1.04–1.40) and 0.85 (95% CI, 0.63–1.07) after extraction and non-extraction treatments, respectively. There was a substantial heterogeneity for the extraction (I2 = 75.2%) and non-extraction (I2 = 70.1%) studies. The follow-up duration (1–10 versus 10–20 years) explained 33% of the heterogeneity, with longer follow-up studies showing more irregularity.

Limitations

The quality of evidence provided by the studies was low. There was a risk of publication bias, and the search was limited to English language.

Conclusions and implications

Post-treatment mandibular irregularity increases are limited. Irregularity increases are slightly greater in patients treated with mandibular premolars extractions, and in patients followed up over longer periods of time.

Registration

The study protocol was not registered.

Factors affecting treatment decisions for Class I malocclusions

INTRODUCTION

Orthodontic treatment planning requires skill and expertise with considerable practice variations. The aims of this study were to review retrospectively the pretreatment records of patients with Class I malocclusion and to identify variables that could play a role in the treatment decision.

METHODS

From the available records of 1500 orthdontic patients, the pretreatment records of 202 patients were selected at random. Inclusion and exclusion criteria were applied, and the surviving records were divided into extraction (n = 92) and nonextraction (n = 92) treatment groups. Skeletal, dental, and soft tissue measurements were obtained from pretreatment lateral cephalograms and dental casts of subjects with bilateral Class I molar relationships. Data were statistically analyzed by binary logistic regression tests.

RESULTS

The results showed that the variables of lower anterior facial height, E-plane to upper lip, and maxillary and mandibular incisor inclinations were significantly increased in the extraction group (P <0.05), whereas spacing in the mandibular arch and increased overbite were statistically significant in the nonextraction treatment group (P <0.05). According to the model, the odds of nonextraction treatment are 1.29 and 1.24 times that of extraction treatment for every 1-mm increase in overbite and spacing in the mandibular arch, respectively.

CONCLUSIONS

Vertical facial pattern, overbite, mandibular tooth size-arch length discrepancy, lip position, and maxillary and mandibular incisor inclinations are a few of the important variables that should not be overlooked when planning orthodontic treatment. The findings of this study could facilitate the treatment planning process for patients with Class I malocclusion.

Effects of Three Different Orthodontic Treatment Methods on the Stability of Mandibular Incisor Alignment

OBJECTIVE

To compare the effects of extraction, non-extraction and air-rotor stripping treatments on mandibular dental arch dimensions, lower incisor positions and evaluate their effects on the stability of the treatment.

STUDY DESIGN

The sample consisted of 44 patients with Class I malocclusion and moderate crowding including 15 patients treated with extraction, 13 with air-rotor stripping (ARS), and 16 with non-extraction treatment. The records were taken at pretreatment (T0), end of active orthodontic treatment (T1), minimum 3 years post-treatment (T2). The model and cephalometric measurements were evaluated. For statistical analyses ANOVA and Welch test was applied.

RESULTS

At post-retention period Little's irregularity indices were increased to 1.96 mm, 2.38 mm and 3.59 mm for extraction, ARS and non-extraction groups respectively (p<0.05). At T1-T2, intercanine widths were decreased significantly at all groups (p<0.05). The arch length and arch depth decreased significantly at extraction group (p<0.05) from T0 to T1 and remained the same at T2 (p>0.05). The lower incisors were retroclined with treatment and slightly proclined at post-retention period in extraction group. In ARS and non-extraction group, lower incisors proclined with treatment and remained the same at post-retention.

CONCLUSION

At all groups the irregularity indices relapsed but did not return to pretreatment values. Although significant increase at intercanine width was only observed in non-extraction treatment, at post-retention phase, intercanine widths were significantly decreased at all groups. The changes at lower incisor inclinations relapsed slightly in extraction group but remained the same in the other groups.

Single tooth torque correction in the lower frontal area by a completely customized lingual appliance

Background

Aim of this study was to analyze the efficacy and precision of the completely customized lingual appliance (CCLA) regarding the single tooth torque correction. The study also examined external apical root resorptions as possible side effects of torque correction and the changings of the periodontal situation.

Methods

A case series of three patients were included. The patients showed a single tooth torque problem with a gingival recession and were treated with the CCLA. Plaster casts before and after treatment and plaster casts of the set up were scanned and superimposed. Deviations between the two plaster casts were analyzed at different points of interest. Changes of the gingival recession were compared before and after treatment. Relative root resorptions were measured by the orthopantomograms. Treatment times were assessed by the records of the patients. Results were presented descriptively.

Results

The mean change of the most apical part of the root reached by the orthodontic treatment was 1.8 ± 0.3 mm. The largest deviation between set up and final model was measured on the occlusal surface of the tooth 36 with 0.8 mm. Most measurement points showed a deviation of 0.5 mm or less. The depths of the gingival recession showed a significant reduction of 4.7 mm. The widths of the gingival recession were reduced by 1.1 mm. The average relative root resorption of the corrected teeth was 2.7 ± 1.5%. The average treatment time was 13.8 ± 4.5 months.

Conclusions

This is the first study showing that the CCLA with its high precision is very effective in correcting single tooth torque problems. Orthodontic torque correction resulted in a significant reduction of gingival recessions and caused only negligible root resorptions.

Mandibular arch orthodontic treatment stability using passive self-ligating and conventional systems in adults: A randomized controlled trial

Objective

This randomized controlled trial aimed to compare the stability of mandibular arch orthodontic treatment outcomes between passive self-ligating and conventional systems during 6 months of retention.

Methods

Fortyseven orthodontic patients with mild to moderate crowding malocclusions not requiring extraction were recruited based on inclusion criteria. Patients (mean age 21.58 ± 2.94 years) were randomized into two groups to receive either passive self-ligating (Damon® 3MX, n = 23) or conventional system (Gemini MBT, n = 24) orthodontic treatment. Direct measurements of the final sample comprising 20 study models per group were performed using a digital caliper at the debonding stage, and 1 month, 3 months, and 6 months after debonding. Paired t-test, independent t-test, and non-parametric test were used for statistical analysis.

Results

A significant increase (p < 0.01) in incisor irregularity was observed in both self-ligating and conventional system groups. A significant reduction (p < 0.01) in second interpremolar width was observed in both groups. Mandibular arch length decreased significantly (p = 0.001) in the conventional system group but not in the self-ligating system group. A similar pattern of stability was observed for intercanine width, first interpremolar width, intermolar width, and arch depth throughout the 6-month retention period after debonding. Comparison of incisor irregularity and arch dimension changes between self-ligating system and conventional system groups during the 6 months were non-significant.

Conclusions

The stability of treatment outcomes for mild to moderate crowding malocclusions was similar between the self-ligating system and conventional system during the first 6 months of retention.

Orthodontic treatment of a mandibular incisor fenestration resulting from a broken retainer

This article describes the orthodontic relapse with mandibular incisor fenestration in a 36-year-old man who had undergone orthodontic treatment 21 years previously. The patient reported that his mandibular 3 × 3 bonded retainer had been partially debonded and broken 4 years earlier. The mandibular left lateral incisor remained bonded to the retainer and received the entire load of the incisors; consequently, there was extreme labial movement of the root, resulting in dental avulsion. As part of the treatment, the root was repositioned lingually using a titanium-molybdenum segmented archwire for 8 months, followed by endodontic treatment, an apicoectomy, and 4 months of alignment and leveling of both arches. The treatment outcomes were excellent, and the tooth remained stable, with good integrity of the mesial, distal, and lingual alveolar bones and periodontal ligament. The 1-year follow-up showed good stability of the results.

Mandibular irregularity index stability following alveolar corticotomy and grafting: A 10-year preliminary study

Objective: 

To evaluate mandibular irregularity index stability following orthodontic treatment facilitated by alveolar corticotomy and augmentation bone grafting (Cort+).

Materials and Methods: 

The irregularity index of 121 orthodontically treated and 15 untreated patient study casts was analyzed at 5 years and 10 years.

Results: 

Cort+ resulted in significantly lower mandibular irregularity index scores at both 5 years (1.5 mm vs 4.2 mm, P &lt; .000) and 10 years (2.1 mm vs 4.1 mm, P &lt; .000) compared with conventionally treated patients.

Conclusions: 

Unmatched samples advise caution with conclusions, but orthodontic therapy combined with Cort+ enhanced the stability of the postorthodontic mandibular irregularity index for at least 10 years in this preliminary study.

Use of Forsus fatigue-resistant device in a patient with Class I malocclusion and mandibular incisor agenesis

Orthodontic treatment in patients with congenitally missing teeth can be challenging. In this case report, we describe the treatment of a 15-year-old girl with mild dental crowding and 2 congenitally missing mandibular incisors. The Forsus fatigue-resistant device was used to move the mandible and the mandibular teeth forward. A new balanced and stable occlusion was achieved after treatment. When the treatment plan includes moving the mandibular teeth forward in a patient with mandibular incisor agenesis, the profile and the skeletal and dental features should be carefully scrutinized to ensure that balanced and esthetic results are achieved.

Stability of maxillary anterior crowding treatment

OBJECTIVE: To evaluate the stability and the relapse of maxillary anterior crowding treatment on cases with premolar extraction and evaluate the tendency of the teeth to return to their pretreatment position. METHODS: The experimental sample consisted of 70 patients of both sex with an initial Class I and Class II maloclusion and treated with first premolar extractions. The initial mean age was 13,08 years. Dental casts' measurements were obtained at three stages (pretreatment, posttreatment and posttreatment of 9 years on average) and the variables assessed were Little Irregularity Index, maxillary arch length and intercanine. Pearson correlation coefficient was used to know if some studied variable would have influence on the crowding in the three stages (LII1, LII2, LII3) and in each linear displacement of the Little irregularity index (A, B, C, D, E) in the initial and post-retention phases. RESULTS: The maxillary crowding relapse ( LII3-2) is influenced by the initial ( LII1), and the teeth tend to return to their pretreatment position. CONCLUSION: The results underline the attention that the orthodontist should be given to the maxillary anterior relapse, primarily on those teeth that are crowded before the treatment.

Um método para o retratamento da recidiva do desalinhamento dentário

INTRODUÇÃO: o ortodontista clínico deve esperar alguma perda do alinhamento dentário obtido durante o tratamento ortodôntico nos casos em que a contenção ortodôntica foi suspensa pelo profissional ou perdida pelo paciente. Nessa situação, os pacientes são, frequentemente, relutantes em novamente usar braquetes para retratar o alinhamento dentário perdido após o tratamento. OBJETIVO: esse artigo descreve o uso de uma técnica simples e eficiente para corrigir pequenas alterações do alinhamento dentário. Esse procedimento, inovador e de baixo custo, produz a resolução da recidiva em poucas semanas. A força usada para realinhar os dentes é obtida através de um fio elastomérico transparente amarrado a uma contenção fixa, de vários filamentos, colada às arcadas superior e inferior.

Recidiva do apinhamento anterossuperior nas más oclusões de Classe I e Classe II tratadas ortodonticamente sem extrações

OBJETIVO: o presente estudo objetivou comparar retrospectivamente a estabilidade pós-contenção do alinhamento dos incisivos anterossuperiores em pacientes com Classe I e Classe II. MÉTODOS: a amostra consistiu de 38 pacientes de ambos os sexos, tratados sem extrações e com mecânica Edgewise, divididos em dois grupos - Grupo 1, constituído por 19 pacientes, com idade inicial média de 13,06 anos, portadores da má oclusão de Classe I com apinhamento anterossuperior inicial maior que 3mm; Grupo 2, constituído por 19 pacientes, com idade inicial de 12,54 anos, portadores da má oclusão de Classe II e, também, com apinhamento anterossuperior inicial maior que 3mm. Foram medidos nos modelos de estudo, das fases pré- e pós-tratamento e pós-contenção, o índice de irregularidade de Little, as distâncias intercaninos e entre os primeiros e segundos pré-molares, a distância intermolares e o comprimento da arcada superior. Para a comparação intragrupo nos 3 tempos de avaliação, utilizou-se os testes ANOVA e Tukey. A comparação intergrupos foi realizada pelo teste t independente. Para verificação da presença de correlação, utilizou-se o teste de correlação de Pearson. RESULTADOS: os resultados evidenciaram maior estabilidade do tratamento no Grupo 2 (Classe II), pois, durante o período pós-contenção, foi observada recidiva do apinhamento dos dentes anterossuperiores menor no Grupo 2 (0,80mm) do que no Grupo 1 (1,67mm). CONCLUSÃO: concluiu-se que o tratamento do apinhamento dos dentes anterossuperiores é mais estável na má oclusão de Classe II do que na má oclusão de Classe I.

Stability and relapse of maxillary anterior crowding treatment in class I and class II Division 1 malocclusions

INTRODUCTION

The maxillary anterior teeth are the most important to facial esthetics because they are the first to show on a smile. Therefore, stability of the maxillary anterior teeth alignment is an important issue. The objective of this study was to compare the stability of maxillary anterior tooth alignment in Class I and Class II Division 1 malocclusions.

METHODS

The sample comprised dental casts of 70 patients with Class I and Class II Division 1 malocclusions and a minimum of 3 mm of maxillary anterior crowding measured by an irregularity index. The patients were treated with extractions and evaluated at pretreatment and posttreatment and at least 5 years after treatment. The sample was divided into 3 groups: group 1, Class I malocclusion treated with 4 first premolar extractions comprising 30 subjects, with an initial age of 13.16 years and 8.59 mm of initial maxillary irregularity; group 2, Class II malocclusion treated with 4 first premolar extractions comprising 20 subjects, with an initial age of 12.95 years and 11.10 mm of maxillary irregularity; and group 3, Class II malocclusion treated with 2 first maxillary premolar extractions comprising 20 subjects, with an initial age of 13.09 years and 9.68 mm of maxillary irregularity.

RESULTS

The decrease in the maxillary irregularity index was significantly greater in group 2 than in group 1 during treatment. The stability of maxillary anterior alignment was 88.12% over the long term; 77% of the linear displacement of the anatomic contact points tended to return to their original positions.

CONCLUSIONS

Stability of maxillary anterior alignment between the 3 groups was similar. The stability of maxillary anterior alignment was high over the long term, but a high percentage of teeth tended to return to their original positions.

Treatment stability with the eruption guidance appliance

INTRODUCTION

Although the eruption guidance appliance has been used to correct Class II malocclusions for many years and its effects have been demonstrated, there is no study on the stability of the changes it produces. Therefore, the objective of this study was to investigate the long-term stability of cephalometric dentoskeletal and occlusal changes after eruption guidance appliance therapy.

METHODS

Thirty-nine patients were evaluated. Occlusal evaluations were made with the peer asseessment rating index, and anterior tooth irregularity was evaluated with the Little irregularity index. Cephalometric and occlusal data were obtained at pretreatment, posttreatment, and postretention. The data were analyzed by dependent 1-way analysis of variance (ANOVA) for comparison between the 3 stages of the experimental group, with the Newman-Keuls test as a second step. To compare the cephalometric experimental group changes with mean population changes, the t test was used.

RESULTS

Cephalometrically, in the postretention stage, overjet remained stable, overbite showed significant relapse, and molar relationship improved toward a Class I relationship. The peer asseessment rating index showed stability of the occlusion. The Little irregularity index demonstrated a statistically significant relapse of crowding in the postretention stage.

CONCLUSIONS

Cephalometrically, overjet and molar relationship were stable in the long term after treatment with the eruption guidance appliance; however, there was relapse of the overbite. Occlusally, correction of the malocclusion elevated by the peer assessment rating was stable. There was relapse of the anterior teeth crowding.

Long-term stability of orthodontic treatment and patient satisfaction. A systematic review

OBJECTIVE

To evaluate morphologic stability and patient satisfaction at least 5 years after orthodontic treatment.

MATERIALS AND METHODS

Published literature was searched through the PubMed and Cochrane Library electronic databases from 1966 to January 2005. The search was performed by an information specialist at the Swedish Council on Technology Assessment in Health Care. The inclusion criteria consisted of a follow-up period of at least 5 years postretention; randomized clinical trials, prospective or retrospective clinical controlled studies, and cohort studies; and orthodontic treatment including fixed or removable appliances, selective grinding, or extractions. Two reviewers extracted the data independently and also assessed the quality of the studies.

RESULTS

The search strategy resulted in 1004 abstracts or full-text articles, of which 38 met the inclusion criteria. Treatment of crowding resulted in successful dental alignment. However, the mandibular arch length and width gradually decreased, and crowding of the lower anterior teeth reoccurred postretention. This condition was unpredictable at the individual level (limited evidence). Treatment of Angle Class II division 1 malocclusion with Herbst appliance normalized the occlusion. Relapse occurred but could not be predicted at the individual level (limited evidence). The scientific evidence was insufficient for conclusions on treatment of cross-bite, Angle Class III, open bite, and various other malocclusions as well as on patient satisfaction in a long-term perspective.

CONCLUSIONS

This review has exposed the difficulties in drawing meaningful evidence-based conclusions often because of the inherent problems of retrospective and uncontrolled study design.

Retrospective analysis of orthodontic treatment outcomes and its relation to postretention stability

OBJECTIVE

The present study was designed to retrospectively evaluate Class I malocclusion cases treated with extraction of the four first premolars, aiming to establish the relationship between the quality of orthodontic treatment outcomes and the long-term occlusal stability.

MATERIAL AND METHODS

The sample comprised 94 patients of both genders, presenting Class I malocclusion, treated with extractions of the four first premolars and Edgewise mechanics. All the patients selected were whites, being 50 males and 44 females. The mean pretreatment age was 13.46 years (s.d. 1.8). The mean treatment time was 2.09 years (s.d. 0.58), the mean retention time was 1.63 years (s.d. 0.73) and the mean time of postretention evaluation was 5.31 years (s.d. 1.61). The dental casts were measured at pretreatment (T1), posttreatment (T2) and postretention (T3), by the PAR index and by the Little irregularity index, and the correction due to treatment (T1-2) and the change at the postretention period (T3-2) were calculated. The descriptive statistics was performed and the Pearson correlation coefficient was applied for the PAR and the Little indices in the total sample, among the times evaluated.

RESULTS

The mean PAR reduction due to treatment was 78.54%, and 66.6%, at the postretention stage related to pretreatment stage. Significant correlations were found for the PAR index at the times evaluated, except between T1 and T2 and between T1-2 and T3. In other words, the higher the treatment correction (T1-2), the lower the posttreatment PAR index (PAR T2) will be, and the higher will be the PAR change at the postretention period (PAR T3-2). Also, the higher the posttreatment PAR score (PAR T2), the higher will be the postretention PAR score (PAR T3).

CONCLUSION

It was concluded that the quality of orthodontic treatment outcomes is not related to the long-term occlusal stability.

Alignment stability in Class II malocclusion treated with 2- and 4-premolar extraction protocols

INTRODUCTION

The purpose of this study was to compare the postretention stability of the correction of mandibular anterior-tooth irregularity in patients with Class II malocclusions whose orthodontic treatments included extraction of 2 or 4 premolars.

METHODS

A total of 66 patients were selected who initially had at least one-half-cusp Class II malocclusions. Nineteen patients (9 male, 10 female) with an initial mean age of 14.04 years were treated with extraction of 2 premolars (group 1); 47 patients (20 male, 27 female) with an initial mean age of 13.03 years were treated with extraction of 4 premolars (group 2). A subgroup of group 2, with a similar amount of initial anterior-tooth irregularity as group 1, was also compared with group 1. Little's irregularity index was used to evaluate anterior tooth irregularity in dental casts obtained from each patient before treatment, after treatment, and 5 years after active treatment. Initial cephalometric variables, initial treatment priority index, pretreatment age, treatment time, and posttreatment time of the groups were compared with t tests. Similarly, Little's irregularity index values at prettreament, posttreatment, and postretention were also compared with the t test. Cephalometric treatment changes within groups were evaluated with dependent t tests.

RESULTS

There were no statistically significant differences in posttretention anterior-tooth irregularity between groups 1 and 2 or the subgroup.

CONCLUSIONS

Treatment of Class II malocclusion with extraction of either 2 maxillary premolars or 4 premolars provides the same mandibular anterior-tooth alignment stability.

Relapse of anterior crowding in patients treated with extraction and nonextraction of premolars

INTRODUCTION

The purpose of this study was to evaluate long-term stability of incisor crowding in orthodontic patients treated with and without premolar extractions.

METHODS

Dental casts and cephalometric records of 98 patients were evaluated before treatment (T1), at posttreatment (T2), and at postretention (T3). Half of the patients had been treated with extractions, and half were treated nonextraction.

RESULTS

Irregularity, as measured by the irregularity index, decreased 5.51 mm in the extraction group and 2.38 mm in the nonextraction group. Mandibular incisor irregularity increased 0.97 mm in the extraction group and 0.99 mm in the nonextraction group, respectively, in the postretention period. Maxillary incisor irregularity relapse was smaller than mandibular incisor relapse for both groups. Intercanine width expanded during treatment. At T3, mandibular intercanine width decreased in both groups, but the differences were not statistically significant. At T3, intermolar width was stable, arch depth decreased, overbite and overjet slightly increased, SN mandibular plane angle decreased, and incisor positions in both groups tended to return to T1 values. Clinically acceptable stability was obtained.

CONCLUSIONS

With the exception of the interincisal angle, no statistically significant differences were recorded between the extraction and nonextraction groups from T2 to T3. No statistically significant correlations were found between any variables studied and mandibular incisor irregularity at T1, T2, and T3.

Correlation between mandibular incisor crown morphologic index and postretention stability

INTRODUCTION

Considering postretention stability as a result of successful orthodontic treatment, we aimed to verify the influence of mandibular-incisor-crown morphology in the relapse of mandibular anterior crowding.

METHODS

The sample comprised 56 white subjects of both sexes with Class I and Class II malocclusions at pretreatment, treated with extraction of 4 first premolars and edgewise mechanics. No patient underwent interproximal stripping during or after treatment. Mean pretreatment age was 13.23 years. Mean treatment time was 2.11 years, and mean posttreatment evaluation time was 5.12 years. Mandibular anterior crowding was measured with the Little irregularity index, and the mesiodistal and buccolingual proportion of the mandibular incisor crowns was measured with the Peck and Peck index. The measurements were obtained from dental casts at the pretreatment, posttreatment, and postretention stages. The Pearson correlation coefficient was calculated to determine the correlation between mandibular-incisor-crown morphology and the amount of postretention-crowding relapse.

RESULTS

The mandibular-incisor-crown morphologic index was not significantly correlated with the amount of mandibular-anterior-crowding relapse.

CONCLUSIONS

Mandibular-incisor-crown morphology is not correlated with the amount of mandibular-anterior-crowding relapse.