Three-dimensional evaluation of tooth movement in Class II malocclusions treated without extraction by orthodontic mini-implant anchorage

Successful management and stability of maxillary class II dentoalveolar protrusion with extractions of upper second and lower third molars, using en-masse distalization and vertical control with bone miniscrews: Adult case report with 7-year follow-up

This case report describes the successful long-term management of a 19-year-old female patient presenting with a skeletal Class II pattern, mild anterior open bite, and mandibular retrognathia. The orthodontic treatment approach involved the distal movement of the maxillary and mandibular dentitions through the extraction of the maxillary second molars and mandibular third molars, combined with the use of extra-alveolar infrazygomatic crest (IZC) and buccal shelf (BS) miniscrews for anchorage. The treatment outcome achieved a stable, well-aligned dentition with ideal intercuspation and an improved facial profile. The 7-year post-treatment records demonstrated a stable occlusion and satisfactory facial aesthetics, confirming the long-term stability of this treatment approach. This case report supports that en-masse distalization of the entire dentition by extracting the upper second molars and lower third molars, coupled with bone miniscrew anchorages, can be a favourable alternative to the conventional premolar extraction approach for the correction of borderline Class II malocclusions.

The effectiveness of the total-maxillary-arch-distalization approach in treating class II division 1 malocclusion: A systematic review

OBJECTIVE

The objective of this review is to assess the effect of total maxillary arch distalization (TMAD) treatment on the dental, skeletal, soft tissues, and airways during non-extraction camouflage treatment of class II division 1 patients.

METHODS

We performed a systematic review of the published data in four electronic databases up to April 2023. We considered studies for inclusion if they were examining the effects of TMAD during treatment of class II division 1 malocclusion in the permanent dentition. Study selection, data extraction, risk of bias assessment, and assessment of the strength of the evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool were performed in duplicate.

RESULTS

Out of the 27 articles that met the initial eligibility criteria, 19 studies were finally selected. Fair to relatively good quality evidence was identified after the risk of bias assessment of the included studies. Out of the 19 selected studies, 5 studies used inter-radicular TADs, 10 studies used modified C- palatal plate (MCPP), 3 studies used infra zygomatic crest (IZC) TADs, 1 study compared buccal TADs versus MCPP, and 1 study compared between cervical headgear and MCPP. The maximum amount of maxillary arch distalization using buccal TADs, MCPP, IZC TADs, and headgear was 4.2mm, 5.4mm, 5mm, and 2.5mm respectively. Different results regarding the amount of dental, skeletal, and soft tissue changes were observed.

CONCLUSIONS

The current low to very low certainty level of evidence suggests that TMAD is effective in camouflaging class II division 1 malocclusion. Future well-conducted and clearly reported randomized controlled trials that include a control group are needed to make robust recommendations regarding the effect of TMAD with different appliances on dental, skeletal, and soft tissue structures.

CLINICAL RELEVANCE

TMAD should be given priority with caution in class II patients who refuse the extraction of premolars. TMAD may be considered an adjunctive approach to solve cases associated with high anchorage need or anchorage loss.

Effectiveness of miniscrew-supported maxillary molar distalization according to temporary anchorage device features and appliance design: systematic review and meta-analysis

OBJECTIVES

To evaluate the effectiveness of distalizing maxillary first molars (U6) by temporary anchorage devices (TADs) according to their location (palatal, buccal, and zygomatic), their number, and appliance design.

MATERIALS AND METHODS

An electronic search of maxillary molar distalization with TADs was done through April 2023. After study selection, data extraction, and risk-of-bias assessment, meta-analyses were performed for the extent of distalization, distal tipping, and vertical movement of U6 using the generic inverse variance and random-effects model. The significance level was set at 0.05.

RESULTS

Forty studies met the inclusion criteria: 4 randomized controlled trials (RCTs), 13 prospective studies, and 23 retrospective studies (total of 1182 patients). Distalization of the U6 was not significantly greater (P = .64) by palatal (3.74 mm) and zygomatic (3.68 mm) than by buccal (3.23 mm) TADs. Distal tipping was significantly higher (P < .001) in nonrigid (9.84°) than in rigid (1.97°) appliances. Vertical movement was mostly intrusive and higher but not significantly different (P = .28) in zygomatic anchorage (-1.16 mm).

CONCLUSIONS

Distalization of U6 with TADs can be an effective and stable treatment procedure, especially when performed with rigid palatal appliances. However, further RCTs or prospective cohort studies are strongly recommended to provide more clinical evidence.

Skeletal and dentoalveolar changes after total maxillary arch distalization using the casted palatal plate vs. buccal miniscrews: A randomized clinical trial

OBJECTIVES

To evaluate treatment changes after total maxillary arch distalization using the casted palatal plate compared with buccal miniscrews.

MATERIAL AND METHODS

This was a randomized, parallel, two-arm, single center trial. Participants were young adults with class II dental relationships and normal or horizontal growth patterns. The patients were treated with total distalization of the maxillary arch and were randomly allocated, according to the anchorage devices, between the plate group and the minivis group. The primary outcomes were sagittal, vertical and angular changes of molars and incisors, while the secondary outcomes were skeletal and soft tissue changes. Outcomes were evaluated on lateral cephalograms and blinding of outcome assessment was implemented. A multivariate analysis of Variance (MANOVA) tests were used and Bonferroni correction for multiple comparisons with P<0.001.

RESULTS

Forty patients (33 females and 7 males; mean age 20±3.1 years) where enrolled. A significant distalization of U6 was observed in both groups (4.33mm in the plate group and 1.88mm in the miniscrews group). It was combined with significant intrusion and non-significant distal tipping of the U6 in the plate group (1.85mm and 3.10°, respectively), while intrusion and distal tipping were non-significant in the miniscrew group (0.8mm and 2°, respectively). Both groups showed significant retraction and palatal inclination without vertical changes of U1. Only the plate group produced significant reduction of ANB and Wits. Upper and lower lips were retracted and the nasolabial angle increased significantly in both groups. There was no significant main effect of the appliance type on the comparison of treatment effects between the two groups (P=0.623). However, univariate comparisons showed that the plaque group showed greater distalization of the U6 (P<0.001).

CONCLUSIONS

Both the casted palatal plate and buccal miniscrews can be viable devices for total distalization of the maxillary arch in the treatment of class II patients. The casted plate may be considered when more extensive distalization is required.

Dental arch form in a sample of Iraqi adults with sickle cell anemia using 3D scanning technique: A cross-sectional study

OBJECTIVE

Sickle cell anemia (SCA) is a hematological condition that involves the synthesis of sickle-shaped, hemoglobin with a short lifespan. This study employed three-dimensional (3D) scanning to pinpoint the most common arch form in a sample of Iraqi adults with SCA.

MATERIALS AND METHODS

A cross-sectional study included maxillary and mandibular casts of 50 patients (25 male and 25 female) with SCA and 50 participants in a control group (25 male and 25 female). The facio-axial (FA) point was digitized on each tooth's labial or buccal surface using SolidWorks® 2020 software. The dimensions of the arch were calculated using two proportional measures and four linear measurements. The dental arch form was determined using 3M templates, and the arches were categorized as square, ovoid, or tapered to establish the most-common arch form. Chi-square was used to compare arch form distribution, and an independent t-test was used to calculate the difference between the control group and the SCA group.

RESULTS

The tapered arch was the predominant form in SCA males and females for the maxilla and the mandible. The molar vertical distance (upper and lower) was significantly higher in males in the SCA group than in males in the control group. There was no significant difference between females in the SCA group and females in the control group.

CONCLUSION

Most patients with SCA had tapered arches. Sagittal jaw dimensions in males with SCA were more affected by marrow hyperplasia. There was little if any to no effect on females with SCA.

Efficiency of maxillary total arch distalization using temporary anchorage devices (TADs) for treatment of Class II-malocclusions: A systematic review and meta-analysis

OBJECTIVES

To evaluate the treatment effects and post-treatment stability of the maxillary total arch distalization using TADs during the non-extraction treatment of class II malocclusions.

MATERIALS AND METHODS

Study involved an electronic search followed by hand searching for randomized and non-randomized clinical studies about maxillary total arch distalization using TADs. After data extraction and risk of bias assessment, meta-analysis was performed for dental, skeletal and soft tissue changes using the Generic-inverse variance approach by use of the mean difference and random-effect model.

RESULTS

In total, 1788 articles were identified, 88 full texts were screened and 22 studies were found eligible; 17 of them were included in the quantitative analysis. The means of distalization/distal tipping of the maxillary first molar were 4mm/3.17° in adults, 3.95mm/1.61° in adolescents after treatment with the Modified C-Palatal plate (MCPP), while they were 2.44mm/2.91° with the inter-radicular mini-screws. Both MCPP's treatment in adults and inter-radicular mini-screws resulted in significant intrusion of U6 (1.64 and 0.75mm, respectively), while insignificant extrusion of U6 was resulted in adolescents treated by MCPP. MCPP appliances resulted in palatal inclination/extrusion of maxillary incisors U1 (6.77°/2mm in adults, 7.46°/3.14mm in adolescents). In contrast, inter-radicular mini-screws resulted in less palatal less amount of palatal inclination/insignificant intrusion of U1 (2.42°/0.14mm). MCPP treatment also resulted in significant changes in the skeletal measurements (SNA, ANB, occlusal and mandibular planes). Insignificant differences were found between subgroups in the retraction amount of maxillary incisors, as well as the upper and lower lips. In the follow-up of adolescents treated with MCPP, a significant amount of mesial movement, mesial tipping, and extrusion (2.94mm, 2.84°, and 3.94mm, respectively) was found. However, skeletal and occlusal corrections of the Class II relationship were maintained.

CONCLUSIONS

Maxillary total arch distalization using TADs can be an effective and stable treatment procedure. However, RCTs or prospective cohort studies are highly recommended to establish a clinical evidence regarding their efficiency.

Evaluation of the stability of the palatal rugae using the three-dimensional superimposition technique following orthodontic treatment

OBJECTIVES

To determine the uniqueness and stability of the palatal rugae after orthodontic treatment.

METHODS

Cast models of untreated subjects (n=50) were obtained twice at intervals of 8-30 months. Cast models of patients who received non-extraction (n=50) and extraction (n=50) orthodontic treatment were obtained before and after treatment at intervals of 11-41 months and 14-49 months, respectively. All 300 cast models were scanned digitally. The palatal rugae were manually extracted and transformed into 3D point clouds using reverse engineering software. An iterative closest point (ICP) registration algorithm based on correntropy was applied, and the minimum point-to-point root mean square (RMS) distances were calculated to analyze the deviation of palatal rugae for scans of the same subject (intrasubject deviation [ISD]) and between different subjects (between-subject deviation [BSD]). Differences in ISD between each group and the deviation between ISD and BSD of all 150 subjects were evaluated.

RESULTS

Significant differences were found in the 150 ISD and 1225 BSD in each group, as well as the 150 ISD and 11175 BSD across all groups. The mean values of ISD in untreated, non-extraction and extraction group were 0.178, 0.229 and 0.333 mm, respectively. When the first ruga was excluded in the extraction group, the mean ISD decreased to 0.241 mm, which was not significantly different from that in the non-extraction group (p=0.314).

CONCLUSIONS

Orthodontic treatment can influence the palatal rugae, especially in cases of extraction. Furthermore, variation mainly existed in the first ruga in cases of extraction. However, palatal rugae are still unique and may be used as a supplementary tool for individual identification.

CLINICAL SIGNIFICANCE

This study indicates that palatal rugae might be applied in the evaluation of orthodontic tooth movement and forensic individual identification. The registration algorithm based on correntropy provides a credible, precise, and convenient method for palatal rugae superimposition.

Bone depth and thickness of different infrazygomatic crest miniscrew insertion paths between the first and second maxillary molars for distal tooth movement: A 3-dimensional assessment

INTRODUCTION

This research aimed to measure the bone depth and thickness of different insertion paths for safe placement of infrazygomatic crest miniscrews between the first (U6) and second maxillary molars (U7) by 3-dimensional (3D) reconstruction and to explore their clinical significance.

METHODS

Cone-beam computed tomography data from 36 adult orthodontic patients were obtained to generate 3D models (n = 72) of the infrazygomatic crest region. For each model, the bone depth and thickness of 27 different insertion paths were measured in the region between U6 and U7. The relationship between bone depth and thickness was statistically analyzed. The clinical risk for each insertion path was assessed according to the impacts of bone depth and thickness on insertion failure.

RESULTS

Maximum bone depth (median, 7.41 mm; mean, 8.42 mm) was present at 13 mm insertion sites with a gingival tipping angle of 50° and a distal tipping angle of 30°. Maximum bone thickness (median, 3.73 mm; mean, 4.00 mm) was present at 17 mm insertion site with a gingival tipping angle of 70° and a distal tipping angle of 30°. There was a significant negative correlation between bone depth and bone thickness (r_s = -0.569, P <0.001). Failure rates were significantly different among different insertion paths (P <0.001).

CONCLUSIONS

Because the bone depth and thickness may affect the safe insertion of infrazygomatic crest miniscrews in the region between U6 and U7 and they are negatively related, a safe insertion protocol design for distal tooth movement should take both into consideration.

Sagittal, rotational and transverse changes with three intraoral distalization force systems: Jones jig, distal jet and first class

Background

To compare the maxillary dentoalveolar changes of patients treated with three distalization force systems: Jones Jig, Distal Jet and First Class appliances, using digitized models.

Material and Methods

The retrospective sample comprised 118 digitized models of 59 patients with Class II malocclusion divided into three groups: Group 1 consisted of 22 patients treated with the Jones Jig appliance; Group 2 consisted of 20 patients treated with the Distal Jet, and Group 3 comprised 17 patients treated with the First Class appliance. Pretreatment and post-distalization plaster models of all patients were digitized and evaluated with OrthoAnalyzerTM software. The pretreatment and post-distalization variables regarding sagittal, rotational and transverse changes were compared by the One-way Analysis of Variance (ANOVA) and Kruskal-Wallis tests, depending on normality.

Results

All appliances presented similar amounts of distalization. The Distal Jet appliance promoted significantly smaller mesial displacement of premolars and greater expansion of posterior teeth. The First Class presented the smallest rotation of the maxillary molars and treatment time.

Conclusions

The distalizers were effective in correcting Class II molar relationship, however, a palatal force seems to provide fewer undesirable effects. Additionally, the degree of rotation and expansion was associated with the side of force application.

Key words:Malocclusion, Angle Class II, Orthodontics, Corrective, Distalizers.

Comparison of 3-dimensional postoperative dental movement in Class III surgical correction with and without presurgical orthodontic treatment

Background

Surgery-first approach (SFA) is an emerging concept that surgically reposition the jaw bones without presurgical orthodontic treatment phase. The study investigated 3D dental movement in the postoperative orthodontic phase with orthodontic-first (OF) and SFA in orthognathic surgery (OGS).

Methods

This study included consecutive 40 patients (20, SF group; 20, OF group) skeletal Class III who underwent 2-jaw OGS correction. The data of cone-beam computed tomography were acquired at 3 stages with the scan of dental models to replace the dentition of the craniofacial images; at before OGS (T0), 1 week after OGS (T1) and at the completion of treatment (T2). The skeletal changes were obtained by overall superimposition. The post-operative dental movement was measured by 3D regional superimposition between T1 and T2.

Results

There were no significant difference in the postsurgical orthodontic movement in both groups except significant upper and lower molars extrusion by 2 mm in the SF group. Both groups exhibited no significant difference in mandibular stability in sagittal and vertical directions. The amount of extrusion in the molars was correlated with a postoperative sagittal mandibular forward movement. The total treatment duration was significantly shorter 230 days in the SF group.

Conclusion

The completion of the orthodontic treatment after OGS in the SFA was mainly accomplished through molar extrusive movement in both arches. The surgical setup of dental occlusion with 4 mm posterior open bite could be corrected during the postsurgical orthodontics in SFA through molar extrusion. The dental occlusion outcome was no different between OF and SFA.

Three-dimensional analysis of tooth movement in Class II malocclusion treatment using arch wire with continuous tip-back bends and intermaxillary elastics

Objective

The aim of this study was to analyze three-dimensional (3D) changes in maxillary dentition in Class II malocclusion treatment using arch wire with continuous tip-back bends or compensating curve, together with intermaxillary elastics by superimposing 3D virtual models.

Methods

The subjects were 20 patients (2 men and 18 women; mean age 20 years 7 months ± 3 years 9 months) with Class II malocclusion treated using 0.016 × 0.022-inch multiloop edgewise arch wire with continuous tip-back bends or titanium molybdenum alloy ideal arch wire with compensating curve, together with intermaxillary elastics. Linear and angular measurements were performed to investigate maxillary teeth displacement by superimposing pre- and post-treatment 3D virtual models using Rapidform 2006 and analyzing the results using paired t-tests.

Results

There were posterior displacement of maxillary teeth (p < 0.01) with distal crown tipping of canine, second premolar and first molar (p < 0.05), expansion of maxillary arch (p < 0.05) with buccoversion of second premolar and first molar (p < 0.01), and distal-in rotation of first molar (p < 0.01). Reduced angular difference between anterior and posterior occlusal planes (p < 0.001), with extrusion of anterior teeth (p < 0.05) and intrusion of second premolar and first molar (p < 0.001) was observed.

Conclusions

Class II treatment using an arch wire with continuous tip-back bends or a compensating curve, together with intermaxillary elastics, could retract and expand maxillary dentition, and reduce occlusal curvature. These results will help clinicians in understanding the mechanism of this Class II treatment.

Clinical application of an intraoral scanner for serial evaluation of orthodontic tooth movement: A preliminary study

The aim of this study was to test the clinical application of an intraoral scanner for serial evaluation of orthodontic tooth movement. The maxillary dentitions of eight patients with fixed orthodontic appliances were scanned using an intraoral scanner at the beginning of treatment (T0), and at 1 month (T1), 2 months (T2), 3 months (T3), and 4 months (T4) after T0. The serial digital models were superimposed on the palatal surface as a reference area, and the linear and angular changes of the central incisors, canines, and first molars were evaluated. The intraclass correlation coefficient and method errors showed that this method was clinically acceptable. Various types of orthodontic tooth movements, including minute movements, could be observed every month. The intraoral scanner and digital superimposition technique enabled the serial evaluation of orthodontic tooth movement without taking serial impressions and/or acquiring radiographs.

Influence of orthodontic mini-implant penetration of the maxillary sinus in the infrazygomatic crest region

INTRODUCTION

Mini-implants are widely used for predictable tooth movements, but insertion is often restricted by anatomic structures. The aims of this study were to investigate the incidence of penetration of mini-implants into the sinus and the relationship between penetration depth and sinus tissue.

METHODS

Data from 32 patients who received mini-implants in the infrazygomatic crest were collected from a data base. The success rate of mini-implants was determined by clinical retrospective analysis. The incidence of penetration, penetration depth, and sinus configuration were investigated and compared between cone-beam computed tomography scans obtained immediately after insertion and before mini-implant removal.

RESULTS

The overall success rate of mini-implants in the infrazygomatic crest was 96.7%, and 78.3% penetrated into the sinus. In the group in which penetration exceeded 1 mm, the incidence of membrane thickening was 88.2%, and the mean value of thickening was 1.0 mm; however, the variable values of penetration in the 1-mm group were only 37.5% and 0.2 mm, respectively (P <0.05).

CONCLUSIONS

The incidence of penetration of infrazygomatic crest mini-implants into the sinus may be high. Penetration through double cortical bone plates with limitation of the penetration depth within 1 mm is recommended for infrazygomatic crest mini-implant anchorage.

Attitudes of orthodontists and laypersons towards tooth extractions and additional anchorage devices

Background

This study investigated the attitudes of orthodontists and laypersons towards the choice of extracting second premolars, rather than first premolars, based on tooth condition and the use of additional anchorage devices.

Methods

Questionnaires were sent to two groups: 324 orthodontists who were members of the Thai Association of Orthodontists, and 100 randomly selected Thai laypersons aged above 20 years and who were unrelated to the field of dentistry. Descriptive and chi-square statistics were used to analyze the data.

Results

Questionnaires were returned by 142 orthodontists (43.8%) and completed by 100 laypersons. The larger the size of the caries lesion in the maxillary second premolar was found, the more orthodontists and laypersons both chose to extract a carious maxillary second premolar instead of a healthy maxillary first premolar. For orthodontists, the use of mini-implant anchorage was significantly related to their extraction decision. Orthodontists who were familiar with mini-implants usage would choose to extract the second premolar at a lower size of extent of caries. Besides, when larger sizes of caries lesions in maxillary second premolars were considered, laypersons tended to have greater acceptance of the use of additional anchorage devices in order to keep the healthy maxillary first premolar.

Conclusions

In this study, tooth condition and the use of anchorage devices are currently the main considerations by both orthodontists and laypersons when selecting the teeth to be extracted for orthodontic treatment.