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

Comparison of aging of nonextraction treated and normal untreated occlusions: 40-year follow up

The objective of this study was to compare the aging changes of the dental arches in patients treated without extractions and untreated normal occlusion subjects after a four-decade follow-up. This retrospective study evaluated two groups: The Treated Group (Group T) comprised 16 patients (6 male; 10 female) presenting with Class I or Class II malocclusions treated orthodontically without extractions. Dental models were evaluated 3 stages: T1 (pretreatment, 13.20 years), T2 (posttreatment, 15.07 years) and T3 (long-term posttreatment, 50.32 years). The Untreated Group (Group UT) consisted of 22 untreated normal occlusion individuals. The dental casts were evaluated at the ages of 13.32 (T1), 17.82 (T2) and 60.95 years (T3). The dental casts were digitized and the irregularity index, intercanine, interpremolar and intermolar widths, overjet and overbite, arch length and perimeter were measured. Intergroup comparisons were performed with independent t tests (P < 0.05). From T1 to T2, the treated group showed maxillary and mandibular crowding and overjet decrease and a maxillary interpremolar and intermolar width increase compared to the untreated group. From T2 to T3, a greater maxillary and mandibular crowding increase and a greater arch length decrease were observed in the treated group compared to the normal occlusion subjects. Overbite increased in the treated group and decreased in the untreated group. The maturational changes of treated patients were different from untreated normal occlusion subjects. Relapse might have contributed for the greater changes observed in incisor crowding and arch length observed in orthodontically treated patients. The aging changes of untreated normal occlusions and nonextraction treated patients, after a four-decade follow-up, proved to be different, indicating that relapse of orthodontic treatment played a role in aging changes of treated patients.

Can vacuum-formed retainers maintain arch dimensions and alignment compared to Hawley and fixed bonded retainers after treatment with fixed appliances? A systematic review and meta-analysis

BACKGROUND

Different types of retention appliances have been proposed over the years, but their effectiveness in maintaining arch dimensions and alignment after orthodontic treatment is still unclear.

AIM

To assess the efficacy of vacuum-formed retainers (VFRs) in preserving arch widths, arch length, and anterior alignment in maxillary and mandibular arches, compared to removable Hawley retainers (HRs) or fixed bonded retainers (FBRs). Search methods: unrestricted literature search of five major databases up to March 2024.

SELECTION CRITERIA

randomized/non-randomized clinical studies comparing VFRs to removable HRs or FBRs.

DATA COLLECTION AND ANALYSIS

after duplicate study selection, data extraction, and risk of bias assessment, random effects meta-analyses of standardized mean differences and their 95% confidence intervals were performed, followed by meta-regressions, sensitivity analyses, and assessment of the quality of evidence with GRADE.

RESULTS

Twenty-two prospective studies (4 non-randomized and 18 randomized controlled trials) involving 1797 patients (mean age 17.01 years, 38.3% males) were included. No significant differences were found in the intercanine width, intermolar width, and arch length between VFRs and HRs, in both arches (P > 0.05). However, VFRs were statistically more effective than HRs in terms of Little's irregularity scores (LII) in the maxilla (eight studies; SMD = -0.42; 95% CI: -1.03 to -0.09; P = 0.02; I2 = 73.4%) but not in the mandible (P = 0.12). No significant differences were reported for all considered outcomes between VFRs and FBRs in in both arches (P > 0.05), except for lower LII, where VFRs were significantly less efficient (eight studies; SMD = 1.49; 95% CI = 0.26-2.7; P = 0.02; I2 = 93%). Follow-up times, risk of bias, and wire type (of FBRs) did not show statistically significant effects on outcome variables. Sensitivity analyses showed robustness of the findings for including non-randomized and postretention studies. The certainty in these estimates was from moderate to low due to the risk of bias and inconsistency.

CONCLUSIONS

Low to moderate quality evidence indicates that VFRs are as effective as HRs in maintaining arch widths, length, and alignment. Low-quality evidence found similar efficacy between VFRs and FBRs, with FBRs being statistically more effective at maintaining lower arch alignment, but the difference was not clinically significant.

REGISTRATION

PROSPERO registration (CRD42024518433).

Non-extraction Approach in a Borderline Case of a Growing Patient: A Case Report

This case presents the effective non-extraction orthodontic treatment of a 13-year-old boy with crowding in both upper and lower arches and deep bite. The patient's chief complaint was irregularly placed maxillary anterior teeth. The active treatment duration lasted for 10 months, which resulted in the successful alleviation of arch crowding and correction of the deep bite without the extraction of any sound erupted tooth. Posttreatment, all of the patient's chief complaints were relieved. Essix retainers were fitted post-debonding, with instructions for the patient to wear them for the subsequent year to maintain the achieved results. This case highlights the efficacy of non-extraction orthodontic strategies in addressing crowding and deep bite issues, drawing the importance of individualized treatment plans to achieve optimal outcomes.

Long-term bone remodeling of maxillary anterior teeth with post-treatment alveolar bone defect in adult patients with maxillary protrusion: a prospective follow-up study

BACKGROUND

Alveolar bone defects, particularly palatal bone dehiscence (PBD) and labial bone fenestration (LBF), occur frequently as a result of retraction of the maxillary anterior teeth. The study aims to explore the long-term bone remodeling of maxillary anterior teeth in adult patients with post-orthodontic treatment PBD and LBF.

MATERIALS AND METHODS

The study includes 24 adult patients with maxillary protrusion (8 males, 16 females) who were treated with extraction of four first premolars and had alveolar bone defects (PBD or LBF) in maxillary anterior teeth following orthodontic treatment. Cone-beam computed tomography imaging measurements were obtained before (T1), after (T2) orthodontic treatment, and after at least 1-year removable thermoplastic retainer retention (T3). The maxillary anterior teeth with PBD or LBF at T2 were divided into the PBD or LBF groups, respectively. The labial and palatal alveolar bone height (ABH), alveolar bone thickness (ABT), and movement of maxillary anterior teeth were measured during retraction (T2-T1) and retention (T3-T2) periods.

RESULTS

The incidence of PBD and LBF in maxillary anterior teeth significantly increased after orthodontic treatment and decreased during the retention period. In the PBD group, the palatal ABH of all maxillary anterior teeth significantly increased from T1 to T2 but decreased from T2 to T3. The ABT of the maxillary central incisor and canine significantly increased on the palatal side and decreased on the labial side during the retention period. In the LBF group, the labial ABT of the maxillary central incisor at the apical level showed a significant decrease from T1 to T2, followed by an increase from T2 to T3. In both groups, the maxillary central incisor showed significant labial movement, with a relative intrusion during the retention period.

CONCLUSION

For adult patients with maxillary protrusion, the alveolar bone defect of maxillary anterior teeth caused by orthodontic retraction significantly improved during the retention period, indicating good long-term bone remodeling. Our findings suggest that a combination of spontaneous reorientation of maxillary anterior teeth and bone remodeling contributed to alveolar bone covering in these patients.

Long term dental transversal stability of Class II division 1 treated with cervical headgear

Introduction:

In several conditions, outcome stability is a great challenge for Orthodontics. Previous studies have reported that relapse commonly occurs along the years after orthodontic treatment finishing.

Objective:

The aim of the present study was to evaluate in the long-term transversal dental arch changes of Class II division 1 patients treated with cervical headgear and fixed appliance.

Methods:

Plaster study casts of 20 patients treated with cervical headgear without dental extractions were 3D-scanned and evaluated in three distinct times: initial (T₁), immediate post-treatment (T₂) and long-term retention (T₃ - minimum 20 years). Transversal teeth distance of maxillary and mandibular canines, premolars and first molars were measured.

Results:

A statistically significant increase during treatment was observed for all maxillary teeth transversal distances (p< 0.05). In turn, a significant reduction was observed in the long term (p< 0.05). For the mandibular teeth, canine transversal distance presented statistically significant constriction in the retention period (p< 0.05). Mandibular first molars distance was significantly expanded by treatment (p< 0.05) and remained stable in the long term. The changes observed for the other teeth or other times were considered not statistically relevant.

Conclusions:

For the accessed sample, transversal changes occurred during treatment and retention phases in Class II division 1 patients treated with cervical headgear and fixed appliance. Relapse was considered statistically relevant, even with the institution of a retention protocol.

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.

A prospective study of the performance of resin bonded bridgework in patients with hypodontia

Congenital absence of teeth presents a number of clinical challenges in young patients, and little is known about the success rate of restorative dental treatment in these patients. The aim of this study was to conduct a prospective clinical study of the performance of resin bonded bridges in patients with hypodontia.

METHODS

A prospective clinical observation study was undertaken in Cork Dental School and Hospital, Ireland. Forty patients (22 males, 18 females; age range 18-21 years) with a confirmed diagnosis of hypodontia rated as mild (n=26), moderate (n=8) or severe (n=6) participated. Following completion of the orthodontic phase of care, all patients had missing teeth restored with resin bonded bridgework (RBB) using a standardised protocol (48 FF; 17CL design). Patients were followed up for 24 months, with recall visits at 6, 12 and 24 months following provision of RBBs.

RESULTS

65 RBBs were provided, 49 in the maxilla and 16 in the mandible; 43 bridges replaced anterior teeth and 22 replaced posterior teeth. After 24 months, 63 bridges were still in function and deemed to satisfy the preset criteria for success and survival. Two posterior bridges had failed due to repeated debond, and this was attributed to occlusal overload. 20% of the patients demonstrated some evidence of post orthodontic relapse, but this did not require further intervention.

CONCLUSION

In the short to medium term, resin bonded bridgework provides a reliable and minimally invasive solution for replacing missing teeth in patients with hypodontia.

Rotation of the upper first molar in Class I, II, and III patients

OBJECTIVE

The aim of this study was to evaluate the mean rotation of the upper first molar (U1(st) M) in cast models from nontreated patients presenting: Class I, skeletal Class II, dental Class II, and skeletal Class III, comparing with Class I orthodontically treated patients.

MATERIALS AND METHODS

One hundred cast models were evaluated with five groups, composed of nontreated Class I (n = 20), dental Class II (n = 20), skeletal Class II (n = 20), skeletal Class III (n = 20), and treated Class I (n = 20). Measurements were taken from photocopies of the upper arches. The angle formed between a line crossing the mesiopalatal and the distal-buccalcusps of the U1(st) M and a line traced on mid palatal junction were measured in all samples.

RESULTS

One-way variance analysis showed that dental Class II group presented great mean rotation of the 1(st) molar (x = 78.95°, SD = 6.19) (P < 0.05), and in 85% of the patients from this group this angle was higher than 73°.

CONCLUSIONS

The skeletal Class II and skeletal Class III groups showed similar mean position of the 1(st) molar, presenting rotation in approximately 50% of the patients. It can be concluded that upper molar rotation occurs mainly in dental Class II patients and shows higher mesial rotation angle.

Assessment of first molars sagittal and rotational position in Class II, division 1 malocclusion

OBJECTIVE

This study assessed the anterior-posterior positioning of the upper and lower first molars, and the degree of rotation of the upper first molars in individuals with Class II, division 1, malocclusion.

METHODS

Asymmetry I, an accurate device, was used to assess sixty sets of dental casts from 27 females and 33 males, aged between 12 and 21 years old, with bilateral Class II, division 1. The sagittal position of the molars was determined by positioning the casts onto the device, considering the midpalatal suture as a symmetry reference, and then measuring the distance between the mesial marginal ridge of the most distal molar and the mesial marginal ridge of its counterpart. With regard to the degree of rotation of the upper molar, the distance between landmarks on the mesial marginal ridge was measured. Chi-square test with a 5% significance level was used to verify the variation in molars position. Student's t test at 5% significance was used for statistical analysis.

RESULTS

A great number of lower molars mesially positioned was registered, and the comparison between the right and left sides also demonstrated a higher number of mesially positioned molars on the right side of both arches. The average rotation of the molars was found to be 0.76 mm and 0.93 mm for the right and left sides, respectively.

CONCLUSIONS

No statistically significant difference was detected between the mean values of molars mesialization regardless of the side and arch. Molars rotation, measured in millimeters, represented ¼ of Class II.

Relapse of incisor crowding: a visit to the Prince of Salina

The management of the retention period after comprehensive orthodontic treatment is of great importance, as a primary goal of clinician. Considerable controversy still surrounds the problem of stability after the retention period. Many studies analyze factors associated to the presence of crowding or incisor irregularity and find predictive features on its relapse. Most studies have reported little o no correlation between the treatment changes in the biological parameters - clinical, biometric (irregularity index, intermolar width, intercanine width, arch length, overjet, overbite), or cephalometric variables- that ocurred and the posttretament and postretention changes that may predict their future development. This article provides a bibliographical overview on the relapse of dental alignment in treated cases. In a brief historical introduction, the first studies on the long-term stability of orthodontic results are analysed. The article then goes on to assess studies that focus attention on anteroinferior alignment before finally studying relapse of upper crowding. It concludes by making some final comments in the light of the bibliography provided and the differents schools regarding retention needs and methods.