Combined distalization and lingual cortex remodeling during mandibular growth for facial profile improvement: a case report

Borderline crowding poses a challenge in deciding whether or not to prescribe premolar extraction. This case report describes the two-phase nonextraction orthodontic treatment of an 11-year-old girl with a hyperdivergent skeletal Class I pattern exhibiting anterior crowding and moderate lip protrusion. The initial phase of treatment included maxillary and mandibular expansion to correct the transverse discrepancy as an early intervention. Subsequently, comprehensive treatment was initiated at the age of 13 years, with fully erupted permanent second molars and growth potential remaining. Phase II treatment involved a second round of maxillary expansion, followed by simultaneous bimaxillary total arch intrusive distalization, using interradicular, temporary skeletal anchorage devices to correct dental crowding and improve the facial profile. Although the limited retromolar space posed a challenge to mandibular tooth distalization, gradual bone remodeling was observed in the lingual cortex of the mandibular body, enabling sufficient orthodontic tooth movement without noticeable side effects. After 4 years 3 months of treatment, her dental crowding was relieved, with significant improvement in the facial profile and proper occlusion. The treatment outcomes remained stable 2 years 4 months after retention.

Orthodontic correction of anterior open bite using skeletal anchorage: systematic review and meta-analysis

The purpose of this study was to investigate the scientific evidence on the short- and long-term effects of orthodontic correction of anterior open bite (AOB) using skeletal anchorage (SA). Clinical studies on the use of SA for AOB in patients with permanent dentition, or at least 12 years of age, were searched. Short- and long-term (≥2 years) outcomes were collected. Mean differences were calculated from pooled data. Twenty-four eligible articles with a total of 362 subjects were selected for inclusion in the meta-analysis. There was a significant increase in overbite (3.88 mm, P < 0.001) and maxillary molar intrusion (-2.15 mm, P < 0.001). The mandible showed counterclockwise rotation with anterosuperior chin movement (all P < 0.001). Long term, the decrease in overbite was 19.9% and decrease in molar intrusion was 22.9%. The decrease in the mandibular projection was 14.6% for ANB (A-point-nasion-B-point angle) and 46.2% for mandibular anteroposterior position. The overall risk of bias in the included studies was rated as moderate to high, and publication bias existed for several key variables. SA for maxillary molar intrusion effectively improved dental and skeletal outcomes, but there was a long-term decrease in overbite and maxillary molar position. The variable data quality, heterogeneity, and publication bias in investigated outcomes are limitations in interpreting the findings.

Adult female skeletal anterior open bite treated by customized lingual orthodontic appliance with miniscrews-assisted in vertical control for perfect orthodontic compensation: A case report with 5-year follow-up

The benefits of lingual orthodontics go beyond appearance. In this case study, a 30-year-old female patient was treated with a custom lingual orthodontic appliance for a Class II high-angle malocclusion, anterior open bite, incisor biprotrusion and crossbite, unilateral second molar scissor bite and dysfunctional tongue thrust. To achieve a counterclockwise rotation of the mandible, implant anchorage was used to control the vertical height. To complete the compensatory therapy, four first premolars were removed. As well as ensuring aesthetics over the 20-month treatment period, the treatment also established a Class I molar relationship, normal overbite and overjet, and improved the facial profile. After a five-year follow-up, the treatment results remained stable.

Evaluation of mechanical properties and morphology of miniscrews Ti6Al4V cold worked versus annealed in artificial bones

PURPOSE

This study aimed to evaluate the influence of different manufacturing procedures (Eli annealed - hot work versus cold worked - cold work) of the raw material under mechanical properties and morphological characteristics of orthodontic miniscrews (MS).

MATERIAL AND METHODS

Thirty MS were randomly separated into 3 types (n=10) according to manufacturer and manufacturing process of the raw material: type A - SIN® annealed (control group); type B - Dentfix® annealed; and, type C - Dentfix® cold worked. MI were inserted in artificial bone blocks, through the manufacturer's specific manual key attached to the digital torquemeter stabilized via custom device. Data of fracture's occurrence was performed using Fisher's exact test. Comparisons between the other two types regarding insertion torque and removal torque were performed using the Mann-Whitney test. Data of fracture torque, shear stress, normal stress and torque ratio was submitted to Kruskal Wallis and Dunn tests (α=0.05). Representative images of surface morphology and fractures were selected.

RESULTS

Type C showed statistically the lowest fracture torque (N.cm) (26.11±0.41) (P=0.0012) and highest torque ratio (%) (98.74±0.85) (P=0.0007). Type C showed statistically higher calculated shear (MPa) (2,432.73±508.41) and normal stress (MPa) (1,403.86±293.39) than type B and type A, showing that they differed in relation to the mechanical strength of the material with which they were made (P=0.0007).

CONCLUSION

Type A fractured completely inside the most apical bone. Type B and type C fractured closer to the transmucosal profile. Cold worked process should be more prone to fractures than those annealed raw manufactured.

The effect of surface roughening on the success of orthodontic mini-implants: A systematic review and meta-analysis

INTRODUCTION

Orthodontic mini-implants are a widely accepted treatment modality in orthodontics; however, the failure rate is moderately high. Surface roughening is the golden standard in conventional oral implantology, and this may prove beneficial for orthodontic mini-implants as well. The objective of this systematic review is to assess the effect of surface roughening on the success rate of orthodontic mini-implants in both adolescent and adult patients undergoing orthodontic treatment.

METHODS

Randomized studies comparing the success of surface-roughened and smooth, machined-surface orthodontic mini-implants were included. A literature search was conducted for 6 electronic databases (Pubmed/Medline, Embase, Cochrane, CINAHL, Web of Science, and Scopus), Clinical trial registry (https://www.

CLINICALTRIALS

gov), and grey literature (Google Scholar). A manual search of the reference lists of included studies was performed. Two authors independently performed the screening, data extraction, risk of bias, and quality assessments. The risk of bias was assessed with the Cochrane risk-of-bias 2.0 Tool. Data were synthesized using a random effect model meta-analysis presented as a forest plot. The certainty in the body of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation tool.

RESULTS

A total of 4226 unique records were screened, and 6 of these were included in the quantitative analysis. Four additional articles were selected for a secondary outcome. A total of 364 orthodontic mini-implants were included in the primary outcome analysis. There was no statistically significant effect of surface roughening on the success of orthodontic mini-implants (odds ratio = 0.63 favoring roughened orthodontic mini-implants; 95% confidence interval, 0.35-1.14). The secondary outcome (ie, the overall failure rate of roughened orthodontic mini-implants) was 6% based on studies with high heterogeneity. Limitations of this study were the risk of bias, study imprecision, and possible publication bias, leading to a very low certainty in the body of evidence.

CONCLUSIONS

There is very low-quality evidence that there is no statistically significant effect of surface roughening on the success of orthodontic mini-implants in humans. The overall failure rate of surface-roughened orthodontic mini-implants was 6%.

FUNDING

No funding was received for this review.

REGISTRATION

This study was preregistered in the Prospective Register of Systematic Reviews (CRD42022371830).

A comparative study on anterior teeth retraction-related hard and soft tissue changes with physiologic anchorage control technique

Aim of this comparative cross-sectional study was to evaluate the effect of anterior teeth retraction and related hard and soft tissue change under physiologic anchorage control in patients with chief complain of protrusive teeth. 68 Class I or II orthodontic patients undergoing four-premolar extraction and requiring maximum or medium anchorage were included. Patients were treated with physiologic anchorage control technique (PASS group, n = 34, 18.6 ± 7.7 years, 10 male and 24 female) and self-ligation technique (Damon group, n = 34, 17.5 ± 5.4 years, 13 male and 21 female), respectively. TADs were used for anchorage reinforcement in Damon group. Pre- and post-treatment cephalograms were collected. Twenty-six skeletal, dental and soft tissue items were measured and analyzed using a blinded method. T test and paired rank-sum test were used for statistical analysis. The baseline characteristics were similar between groups (P > 0.05). After treatment, inter-group comparison showed statistically significant differences in the decrease of skeletal measurements ∠ANB (- 0.73 ± 1.05° in PASS group and - 0.25 ± 0.84° in the Damon group), Wits value (- 2.56 ± 2.29 mm in PASS group and - 0.47 ± 2.15 mm in Damon group) and soft tissue measurement UL-E (- 2.75 ± 1.36 mm in PASS group and - 2.03 ± 1.30 mm in Damon group) and the increase of FCA and Z angle, which was 2.03 ± 2.12°and 9.52 ± 4.78°in PASS group and 0.97 ± 2.12°and 6.96 ± 4.43°in Damon group, respectively (P < 0.05). Our results indicated that significant anterior teeth retraction and profile improvement could be achieved with PASS technique without additional anchorage devices. Appropriate application of physiologic anchorage control could reduce the dependence of TADs for anterior teeth retraction.

Success rates of single-thread and double-thread orthodontic miniscrews in the maxillary arch

AIM

There is limited research on the clinical performance of double-thread orthodontic miniscrews. This study aimed to compare the stability of double-thread and single-thread orthodontic miniscrews and identify the potential associations between patient-related and location-related factors with miniscrew stability.

METHODS

This retrospective cohort study involved 90 orthodontic miniscrews (45 single-thread, 45 double-thread) with identical dimensions (8 mm length, 1.6 mm diameter). The screws were inserted in various locations within the upper jaw of 83 patients (54 females, 29 males; mean age = 15.1 ± 2.4 years). Failure was defined as excessive mobility or loss of miniscrew after placement. The data recorded were patient age, gender, insertion site, side of insertion (buccal or lingual), duration of force application, and failure occurrence.

RESULTS

The overall success rate within the sample was 92.2%. Double-thread miniscrews exhibited a significantly higher success rate than single-thread miniscrews (P = 0.049), with 97.8% and 86.7% success rates, respectively. Gender, age, insertion location, and side of insertion did not show significant associations with failure (P > 0.05). Log-rank analysis revealed a significant difference between the two groups (P = 0.046), indicating a higher probability of survival for the double-thread design.

CONCLUSIONS

The overall success rate of orthodontic miniscrews was high in the present sample. Double-thread miniscrews placed in various locations within the maxillary arch demonstrated superior stability and survival rates compared to their single-thread counterparts. Therefore, double-thread miniscrews may be preferred when bone quality is inadequate, such as in young patients.

Current status of the biomechanics of extra-alveolar miniscrews

Temporary skeletal anchorage devices such as miniscrews are frequently used nowadays. Compared to miniplates, miniscrews are much less expensive and technically easier to place and remove; they are popular and can be easily placed by an orthodontist. Extra-alveolar miniscrews offer benefits compared to inter-radicular miniscrews, such as reduced risk of root damage and the lack of interference with the mesiodistal tooth movement. They are particularly useful for addressing anchorage loss issues and enabling specific tooth movements such as total arch maxillary and mandibular retraction, posterior distalization, molar protraction, molar intrusion, occlusal plane control, and midline correction. The present paper discusses the current biomechanics principles related to the use of extra-alveolar miniscrews placed in the infrazygomatic and mandibular buccal shelf.

Biomechanical and clinical considerations in deep bite treatment using temporary skeletal anchorage devices

Deep bite is usually treated by intrusion of the anterior teeth, extrusion of the posterior teeth, or a combination thereof. Various traditional methods have been used to correct deep bites, but they can cause negative side effects. Recently, temporary skeletal anchorage devices (TSADs) have been used to intrude the anterior teeth simply and efficiently without side effects. The amount of incisal exposure at rest should be considered as the first factor in determining which tooth segment should be intruded to correct a deep bite. The center of resistance of the anterior teeth should be considered to achieve the proper biomechanics when intruding them. The location of TSADs should be determined to ensure sufficient interradicular bone to achieve the desired tooth movement. Therefore, clinicians should understand the biomechanical and clinical considerations to correct a deep bite using TSADs.

A finite element analysis of stress distribution with various directions of intermaxillary fixation using orthodontic mini-implants and elastics following mandibular advancement with a bilateral sagittal split ramus osteotomy

OBJECTIVE

This finite element analysis (FEA) aimed to assess the stress distribution in the mandible and fixation system with various directions of the intermaxillary fixation (IMF) using mini-implants (MIs) and elastics following mandibular advancement with a bilateral sagittal split ramus osteotomy (BSSRO).

MATERIALS AND METHODS

A total of nine mandibular advancement models were set according to the position of the MIs (1.6 mm in diameter, 8 mm in length) and direction of the IMF elastics (1/4 inch, 5 oz). Major and minor principal stresses in the cortical and cancellous bones, von Mises stresses in the fixation system (miniplate and monocortical screws), and bending angles of the miniplate were analysed.

RESULTS

Compressive and tensile stress distributions in the mandible and von Mises stress distributions in the fixation system were greater in models with a Class III IMF elastic direction and a higher IMF elastic force than in models with a Class II IMF elastic direction and a lower IMF elastic force. The bending angle of the miniplate was negligible.

CONCLUSIONS

Stress distributions in the bone and fixation system varied depending on the direction, amount of force, and position of IMF elastics and MIs. Conclusively, IMF elastics in the Class II direction with minimal load in the area close to the osteotomy site should be recommended.

Cephalometric and digital model analysis of dentoskeletal effects of infrazygomatic miniscrew vs. Essix- anchored Carriere Motion appliance for distalization of maxillary buccal segment: a randomized clinical trial

TRIAL DESIGN

Parallel.

OBJECTIVE

To compare skeletally anchored Carriere Motion appliance (CMA) for distalization of the maxillary buccal segment vs. Essix anchored CMA.

METHODS

Thirty-two class II malocclusion patients were randomly allocated into two equal groups. One group was treated with infrazygomatic (IZC) miniscrew- anchored CMA (IZCG) and the other group treated with Essix retainer- anchored CMA (EXG). Two lateral cephalograms and two digital models for upper and lower arches were taken for each patient: immediately before intervention and after distalization had been completed.

RESULTS

Distalization period was not significantly different between the two groups. In contrast to EXG, IZCG showed insignificant difference in ANB, lower incisor proclination, and mesial movement of the lower first molar. There was significant rotation with distal movement of maxillary canine and first molar in both groups.

CONCLUSION

IZC anchored CMA could eliminate the side effects of class II elastics regarding lower incisor proclination, mesial movement lower molars with a more significant amount of distalization of the maxillary buccal segment but with significant molar rotation.

TRIAL REGISTRATION

The ClinicalTrials.gov Protocol Registration and Results System (PRS) has this RCT registered as (NCT05499221) on 12/08/2022.

Dental, skeletal and soft tissue changes after bimaxillary protrusion treatment with temporary anchorage devices using different retraction mechanics

BACKGROUND

Temporary anchorage devices (TADs), which are absolute anchorage, are used for retraction of the anterior teeth in cases of severe bimaxillary protrusion. There have been a number of studies regarding anterior tooth movement using TADs performed by simulation systems and actual treated materials with sliding mechanics. However, there are few studies regarding anterior tooth movement using TADs treated by loop mechanics The purpose of this study was to investigate the effect of TADs in anterior tooth movement using loop mechanics performed in actual cases of bimaxillary protrusion.

METHODS

This study was performed in 20 adult patients with severe bimaxillary protrusion treated with four bicuspid extraction with sliding or loop mechanics (n = 10 in each mechanics) using TADs. The skeletal and denture patterns, as well as the soft tissue profile from pre-treatment (T0) and post-treatment (T1) lateral cephalograms, were compared between sliding and closing loop mechanics.

RESULTS

The use of TADs is useful for retraction of anterior teeth without molar anchorage loss. in sliding and loop mechanics. The upper anterior teeth were less lingual tipped and lower anterior teeth were more upright resulting in less clockwise rotation of the occlusal plane in loop mechanics compared to sliding mechanics.

CONCLUSION

An oblique retraction force vector with a lower point of application causes less intrusion and more lingual tipping of upper anterior teeth as well as more clockwise rotation of the occlusal plane compared to a parallel retraction force vector.

Comparative assessment of orthodontic clear aligner versus fixed appliance for anterior retraction: a finite element study

BACKGROUND

The aim of this study is to conduct a comparative evaluation of different designs of clear aligners and examine the disparities between clear aligners and fixed appliances.

METHODS

3D digital models were created, consisting of a maxillary dentition without first premolars, maxilla, periodontal ligaments, attachments, micro-implant, 3D printed lingual retractor, brackets, archwire and clear aligner. The study involved the creation of five design models for clear aligner maxillary anterior internal retraction and one design model for fixed appliance maxillary anterior internal retraction, which were subsequently subjected to finite element analysis. These design models included: (1) Model C0 Control, (2) Model C1 Posterior Micro-implant, (3) Model C2 Anterior Micro-implant, (4) Model C3 Palatal Plate, (5) Model C4 Lingual Retractor, and (6) Model F0 Fixed Appliance.

RESULTS

In the clear aligner models, a consistent pattern of tooth movement was observed. Notably, among all tested models, the modified clear aligner Model C3 exhibited the smallest differences in sagittal displacement of the crown-root of the central incisor, vertical displacement of the central incisor, sagittal displacement of the second premolar and second molar, as well as vertical displacement of posterior teeth. However, distinct variations in tooth movement trends were observed between the clear aligner models and the fixed appliance model. Furthermore, compared to the fixed appliance model, significant increases in tooth displacement were achieved with the use of clear aligner models.

CONCLUSIONS

In the clear aligner models, the movement trend of the teeth remained consistent, but there were variations in the amount of tooth displacement. Overall, the Model C3 exhibited better torque control and provided greater protection for posterior anchorage teeth compared to the other four clear aligner models. On the other hand, the fixed appliance model provides superior anterior torque control and better protection of the posterior anchorage teeth compared to clear aligner models. The clear aligner approach and the fixed appliance approach still exhibit a disparity; nevertheless, this study offers a developmental direction and establishes a theoretical foundation for future non-invasive, aesthetically pleasing, comfortable, and efficient modalities of clear aligner treatment.

Comparison between microporous and nanoporous orthodontic miniscrews : An experimental study in rabbits

PURPOSE

Surface characteristics of orthodontic miniscrews might affect survival rates and removal torque values (RTVs). This experimental study aimed to clarify whether and why a microporous or nanoporous surface promotes higher survival rates and RTVs for orthodontic miniscrews.

METHODS

Using a split-leg design, one set each of nonporous (sham control, n = 24) and microporous (control, n = 6), and three sets of nanoporous (experimental, n = 6 per set) miniscrews were implanted in the tibias of 12 New Zealand rabbits and immediately loaded with 1.5 N nickel-titanium coil springs for 12 weeks. The surface morphology, micropores, and nanotube diameters of the miniscrews were examined using scanning electron microscopy and field-emission scanning electron microscopy. The surface composition and thickness were determined using Auger electron spectroscopy. The survival rates and RTVs of each set were assessed.

RESULTS

The nanoporous miniscrews had higher survival rates, RTVs (p < 0.001), and thicker nanotube oxide thicknesses (p < 0.001) than the nonporous and microporous miniscrews. The nonporous and microporous miniscrews had no nanotube structures. The surface oxide composition was titanium dioxide (TiO2). The threshold RTV, TiO2 thickness, and nanotube diameter of nanoporous miniscrews needed to promote the experimental survival rate to 100% was determined to be 6.6 ± 0.8 N-cm (p < 0.05), 22.5 ± 4.8 nm (p < 0.05), and 17.6 ± 2.3 nm or above, respectively.

CONCLUSION

Nanoporous surfaces promoted higher survival rates and RTVs than microporous miniscrews. This could be due to TiO2 nanotube structures with thicker oxide layers in nanoporous miniscrews.

Comparison between effects of mini-implant anchorage and face-bow anchorage in orthodontics for children

To study the values of mini-implant anchorage in orthodontics for children in the mixed dentition stage, 78 children in the mixed dentition stage who had accepted orthodontic treatment in our hospital from January 2020 to January 2021 were enrolled into this study. All children were treated with straight-wire appliance. According to their anchorages, children were divided into observation group and control group based on the random number table. Children in the control group used face-bow to control the anchorages and children in the observation group used mini-implants to control the anchorages. After treatment, the upper central incisor convex distance difference, inclination angle of the upper central incisor, displacement of the molar, gingival health, masticatory function, treatment effect and adverse reaction rate of children in two groups were compared. One year after treatment, compared with children in the control group, children in the observation group had smaller the upper central incisor convex distance difference, inclination angle of the upper central incisor, displacement of the molar, small scores of plaque index (PLI), bleeding index (BI) and gingival index (GI), stronger biting force and higher masticatory efficiency, lower adverse reaction rate during treatment, better treatment effect, higher satisfaction of orthodontic treatment. And differences of all the above indexes were statistically significant (p < 0.05). Mini-implant anchorages have good stability and directive force, and have certain values in orthodontics for children in the mixed dentition stage.

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.

Assessment of the efficacy of various maxillary molar intrusion therapies: a systematic review

AIMS

To systematically assess the efficacy of the various interventions used to intrude maxillary molars. Furthermore, to evaluate associated root resorption, stability of intrusion, subsequent vertical movement of mandibular molars, cost effectiveness, compliance, patient reported outcomes and adverse events.

METHODS

A pre-registered and comprehensive literature search of published and unpublished trials until March 22nd 2023 with no language restriction applied in PubMed/Medline, Embase, Scopus, DOSS, CENTRAL, CINAHL Plus with Full Text, Web of Science, Global Index Medicus, Dissertation and Theses Global, ClinicalTrials.gov, and Trip (PROSPERO: CRD42022310562). Randomized controlled trials involving a comparative assessment of treatment modalities used to intrude maxillary molars were included. Pre-piloted data extraction forms were used. The Cochrane Risk of Bias tool was used for risk of bias assessment, and The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was used for certainty of evidence appraisal.

RESULTS

A total of 3986 records were identified through the electronic data search, of which 24 reports were sought for retrieval. Of these, 7 trials were included. One trial was judged at high risk of bias, while the others had some concerns. Based on individual small sample studies, maxillary molar intrusion was achieved using temporary anchorage devices (TADs) and rapid molar intruder appliance (RMI). It was also observed to a lesser extent with the use of open bite bionator (OBB) and posterior bite blocks. The molar intruder appliance and the posterior bite blocks (spring-loaded or magnetic) also intruded the lower molars. Root resorption was reported in two studies involving TADs. None of the identified studies involved a comparison of conventional and TAD-based treatments for intrusion of molars. No studies reported outcomes concerning stability, cost-effectiveness, compliance and patient-reported outcomes. Insufficient homogeneity between the included trials precluded quantitative synthesis. The level of evidence was very low.

CONCLUSIONS

Maxillary molar intrusion can be attained with different appliances (removable and fixed) and with the use of temporary anchorage devices. Posterior bite blocks (spring-loaded or magnetic) and the RMI offer the additional advantage of intruding the mandibular molars. However, stability of the achieved maxillary molar intrusion long term is unclear. Further high-quality randomized controlled trials are needed.

Root resorption during maxillary molar intrusion with clear aligners: a randomized controlled trial

OBJECTIVES

To compare changes in maxillary molar root resorption, intrusion amount, dentoskeletal measures, and maximum bite force (MBF) between clear aligners (CA) and fixed appliances with miniscrew (FM) during molar intrusion.

MATERIALS AND METHODS

Forty adults with anterior open bite were randomized into either CA or FM groups. Lateral cephalograms, cone-beam computed tomography (CBCT), and MBF were collected at pretreatment (T0) and 6 months of treatment (T1). Maxillary molar intrusion in FM were intruded by nickel-titanium (NiTi) closed-coil spring delivered force (150 grams/side) while clear aligners combined with squeezing exercise were performed in CA. Parametric tests were used for statistical analysis.

RESULTS

After 6 months of treatment, significant root resorption of 0.21-0.24 mm in CA and 0.38-0.47 mm in FM were found while maxillary molars were intruded 0.68 and 1.49 mm in CA and FM, respectively. CA showed significant less root resorption and intrusion than FM. Overbite, bite closing, and MBF increased significantly. CA showed significantly less overbite and SN-MP changes but more MBF increase than FM. MBF in CA was correlated with the amount of maxillary molar intrusion (r = 0.736, P < .05).

CONCLUSIONS

Maxillary molar intrusion and root resorption in CA were half the amount in FM in 6 months. The amount of maxillary molar root resorption was one-third of the intrusion distance. CA displayed less overbite increase and bite closing but more MBF increase than FM. MBF in CA was positively correlated with the molar intrusion amount.

Rate and anchorage loss during en-masse retraction between friction and frictionless mechanics: A randomized clinical trial

OBJECTIVE

To compare rate and anchorage loss during en-masse retraction of anterior maxillary teeth between friction mechanics (FM) and frictionless mechanics (FLM).

SETTING AND SAMPLE POPULATION

Thirty-eight patients requiring en-masse retraction of protruded anterior maxillary teeth were randomly allocated into FM and FLM groups.

METHODS

En-masse retraction with sliding mechanics (FM) using an elastomeric chain was compared with continuous mushroom loop archwire mechanics (FLM). Study models and lateral cephalograms were taken before (T1) and immediately after retraction (T2). The primary outcome was the rate of en-masse retraction. Anchorage loss was the secondary outcome. Intergroup comparison was performed using an independent t test (P < .05).

RESULTS

Baseline characteristics were similar between groups. Thirty-six patients completed the trial. Two patients were lost to follow-up in the FLM group. The rate of en-masse retraction did not differ significantly (P = .625) between FM (0.7 mm/mo) and FLM (0.8 mm/mo) groups. The intragroup comparison showed significant anchorage loss in FM (2.28 mm) and FLM (1.13 mm) groups; however, the intergroup comparison showed no statistically significant difference (P = .093). Maxillary first molar showed a statistically significant change in angulation between the two mechanic groups (P < .001). Vertical movement of the maxillary incisor and first molar showed no significant difference between FM and FLM groups (P = .143, P = .546, respectively).

CONCLUSIONS

The rate of en-masse retraction and anchorage loss was comparable between the FM and FLM groups. Significant anchorage loss was seen with both mechanics. The result suggests that both the mechanic group require external reinforcement to prevent anchorage loss.

Analysis of oral microbiome on temporary anchorage devices under different periodontal conditions

BACKGROUND

Temporary anchorage devices (TADs) are maximum anchorages that have been widely used in orthodontic treatment. The aim of the study was to uncover whether a history of periodontitis would influence microbiome colonization on the TAD surface.

RESULTS

Patients were grouped by periodontal evaluations before the orthodontic treatment. Patients with healthy periodontal conditions were classified as the healthy group, and patients diagnosed with periodontitis stage II or even worse were classified as the periodontitis group. Scanning electron microscopy (SEM) was used to analyze the existence of biofilm on the surface of 4 TADs from the healthy group and 4 TADs from the periodontitis group. Fifteen TADs from the healthy group and 12 TADs from the periodontitis group were collected. The microorganisms on the surface of TADs were harvested and analyzed by 16S rRNA gene sequencing. α-diversity indices and β-diversity indices were calculated. Wilcoxon's test was used to determine differences between genera, species as well as KEGG functions. SEM analysis revealed bacteria colonization on the surface of TADs from both groups. Principal coordinate analysis (PCoA) based on β diversity revealed differential sample clusters depending on periodontal conditions (P < 0.01). When comparing specific genera, Fusobacterium, Porphyromonas, Saccharibacteria_(TM7)_[G-1], Dialister, Parvimonas, Fretibacterium, Treponema were more enriched in TADs in the periodontitis group. In the KEGG analysis, TADs in the periodontitis group demonstrated enriched microbial activities involved with translation, genetic information processing, metabolism, and cell motility.

CONCLUSIONS

This analysis elucidated the difference in total composition and function of TADs oral microorganisms between patients periodontally healthy and with periodontitis.

A pattern of microbiological colonization of orthodontic miniscrew implants

INTRODUCTION

Current orthodontic literature reveals a lack of studies on bacterial colonization of orthodontic miniscrew implants (MSI) and their role in the stability of MSI. This study aimed to determine the pattern of microbiological colonization of miniscrew implants in 2 major age groups, to compare it with the microbial flora of gingival sulci in the same group of patients and to compare microbial flora in successful and failed miniscrews.

METHODS

The study involved 102 MSI placed in 32 orthodontic subjects in 2 age groups: (1) aged ≤14 years and (2) aged >14 years. Gingival and peri-mini implant crevicular fluid samples were collected using sterile paper points (International Organization for Standardization no. 35) >3 months and processed by conventional microbiologic culture and biochemical techniques. A microbiologist characterized and identified the bacteria, and the results were subjected to statistical analysis.

RESULTS

Initial colonization was reported within 24 hours, with Streptococci being the dominant colonizer. The relative proportion of anaerobic bacteria over aerobic bacteria increased over time in peri-mini implant crevicular fluid. Group 1 had greater Citrobacter (P = 0.036) and Parvimonas micra (P = 0.016) colonizing MSI than group 2. Failed MSI showed a significantly higher presence of Parvimonas micra (P = 0.008) in group 1 and Staphylococci (P = 0.008), Enterococci (P = 0.011), and Parvimonas micra (P <0.001) in group 2.

CONCLUSIONS

Microbial colonization around MSI is established within 24 hours. Compared to gingival crevicular fluid, peri-mini implant crevicular fluid is colonized by a higher proportion of Staphylococci, facultative enteric commensals and anaerobic cocci. The failed miniscrews showed a higher proportion of Staphylococci, Enterobacter, and Parvimonas micra, suggesting their possible role in the stability of MSI. The bacterial profile of MSI varies with age.

Effects of rapid maxillary expansion on anchorage alveolar bone meta-analysis

PURPOSE

Rapid maxillary expansion (RME) is a routine method for correcting transverse maxillary deficiency. This paper investigated the effect of RME on anchorage alveolar bone and examined the differences between micro-implant-assisted RME and conventional RME.

METHODS

Relevant articles were selected from the PubMed, EMBASE and Cochrane Central Register of Controlled Trials databases. Review Manager software (v.5.3) was used for the pooled analysis and Cochran Q and I2 statistic tests were used to assess the heterogeneity.

RESULTS

Following conventional RME, the distal buccal alveolar bone thickness and the mesiobuccal alveolar thickness of the maxillary first molars were significantly reduced. Hyrax (standard mean difference [SMD]: -0.93, 95% confidence interval [CI]: -1.20-0.66) and Haas procedures (SMD: -0.88, 95% CI: -1.40-0.36) significantly reduced the buccal vertical alveolar height of the maxillary first molars. Similar results were obtained for the maxillary first premolars following RME. The thickness of the buccal alveolar bone decreased with conventional RME compared to when using the method assisted by micro-implants.

CONCLUSIONS

Conventional RME can reduce the thickness and vertical height of maxillary alveolar bone, and there is less loss of alveolar bone when using micro-implant-assisted RME. Further research is needed to validate the findings.

Temporary anchorage devices in orthodontics: a bibliometric analysis of the 50 most-cited articles from 2012 to 2022

OBJECTIVES

To identify and analyze the 50 most cited articles on temporary anchorage devices (TADs) and investigate the achievement and development of scientific research about the topic through a bibliometric analysis.

MATERIALS AND METHODS

On August 22, 2022, a computerized database search was performed to detect papers published in the scientific literature about TADs from 2012 to 2022. Metrics data were identified using the Incites Journal Citation Reports (Clarivate Analytics) data set. The Scopus database was used to obtain information on the authors' affiliations, country of origin, and h-index. Key words were automatically harvested from the selected articles to implement the visualized analysis.

RESULTS

From a total of 1858 papers screened by searching the database, a list of the top 50 most cited articles was created. The total number of citations collected by the 50 most cited articles in TADs was 2380. Among the 50 most cited articles on TADs, 38 were original research papers (76.0%) and 12 were reviews (24.0%). As shown by the key word-network analysis, Orthodontic anchorage procedure was identified as the larger node.

CONCLUSIONS

Findings of this bibliometric study showed an increasing number of citations for papers on TADs, accompanied by a simultaneous rise in scientific interest in this topic in the past decade. The present work identifies the most influential articles, emphasizing the journals, the authors, and the topics addressed.

Comparison of mechanical stability of mini-screws with resorbable blasting media and micro-arc oxidation surface treatments under orthodontic forces: An in vitro biomechanical study

INTRODUCTION

The aim of this study was to compare the primary stability of mini-screws with different surface treatments such as resorbable blasting media (RBM) and micro-arc oxidation (MAO) under in vitro orthodontic forces.

MATERIAL AND METHODS

Thirty-six self-drilling TiAl6V4-ELI grade 23 titanium alloy 1.6×8mm mini-screws were inserted into polyurethane foam blocks and divided into three groups according to surface properties: machine surface (MS), RBM-treated, and MAO-treated. An orthodontic force of 150g was applied to the mini-screws using NiTi coils. Maximum insertion torque (MIT) and maximum removal torque (MRT) were measured with a digital torque screwdriver during insertion and removal. For each mini-screw, stability measurements were made with the Periotest M device at day 0 and weeks 1, 2, 4, 8, and 12.

RESULTS

Significant differences in MIT were observed between all groups in pairwise comparisons (P<0.001) with the highest value in the MAO-treated group and the lowest in the MS group. The mean MRT values differed in all three groups (P=0.001). In pairwise comparisons of MRT, only the difference between MS group and RBM-treated group was significant. The highest value was observed in the RBM-treated group, while the lowest value was observed in the MS group. Periotest values were significantly higher in the MAO-treated group than the RBM-treated group at weeks 8 and 12. A positive significant correlation was found between MIT and MRT in all groups. No significant correlation was found between MIT, MRT and Periotest values in all groups.

CONCLUSION

RBM-treated group was significantly higher than the MS group in MIT and MRT values. According to Periotest values, RBM-treated group was found to be significantly more stable than the MAO-treated group at weeks 8 and 12. Therefore, RBM surface treatment was found to be more favourable than other surfaces to increase success rate in clinical applications.

Comparative analysis of two navigation techniques based on augmented reality technology for the orthodontic mini-implants placement

To analyze and compare the accuracy and root contact prevalence, comparing a conventional freehand technique and two navigation techniques based on augmented reality technology for the orthodontic self-drilling mini-implants placement. Methods Two hundred and seven orthodontic self-drilling mini-implants were placed using either a conventional freehand technique (FHT) and two navigation techniques based on augmented reality technology (AR TOOTH and AR SCREWS). Accuracy across different dental sectors was also analyzed. CBCT and intraoral scans were taken both prior to and following orthodontic self-drilling mini-implants placement. The deviation angle and horizontal were then analyzed; these measurements were taken at the coronal entry point and apical endpoint between the planned and performed orthodontic self-drilling mini-implants. In addition, any complications resulting from mini-implant placement, such as spot perforations, were also analyzed across all dental sectors.Results The statistical analysis showed significant differences between study groups with regard to the coronal entry-point (p < 0.001), apical end-point(p < 0.001) and angular deviations (p < 0.001). Furthermore, statistically significant differences were shown between the orthodontic self-drilling mini-implants placement site at the coronal entry-point (p < 0.0001) and apical end-point (p < 0.001). Additionally, eight root perforations were observed in the FHT group, while there were no root perforations in the two navigation techniques based on augmented reality technology.Conclusions The navigation techniques based on augmented reality technology has an effect on the accuracy of orthodontic self-drilling mini-implants placement and results in fewer intraoperative complications, comparing to the conventional free-hand technique. The AR TOOTH augmented reality technique showed more accurate results between planned and placed orthodontic self-drilling mini-implants, comparing to the AR SCREWS and conventional free-hand techniques. The navigation techniques based on augmented reality technology showed fewer intraoperative complications, comparing to the conventional free-hand technique.

Accuracy of digital workflow for placing orthodontic miniscrews using generic and licensed open systems. A 3d imaging analysis of non-native .stl files for guided protocols

BACKGROUND

This study aimed to assess the accuracy of digital workflow for guided insertion of miniscrews in the anterior palate using restorative implant dentistry software and licensed software for orthodontic applications.

METHODS

Twenty subjects (8 males, 12 females, mean age = 16.7 ± 2.1 years) were prospectively selected to receive guided insertion of bicortical palatal miniscrews. Virtual planning was performed using restorative implant dentistry software (Blue Sky Plan*, version 4.7) (group 1 = 10 subjects) and licensed orthodontic software (Dolphin Imaging Software, version 11.0) (group 2 = 10 subjects). A specific 3D Imaging technology was applied to permit the registration of the planned and achieved position of the miniscrews based on the superimposition of maxillary models. The angular deviation (accuracy error) between the planned and the achieved positions of the miniscrews were recorded. Independent Student's test was used with statistical significance set at p value < 0.05.

RESULTS

The mean accuracy error recorded in group 1 was 7.15° ± 1.09 (right side) and 6.19 ± 0.80 (left side) while the mean error in group 2 was 6.74° ± 1.23 (right side) and 5.79 ± 0.95 (left side). No significant differences were recorded between the two groups (p > 0.05); instead, miniscrews placed on the right side were almost one degree higher than the left side (p < 0.05) in both groups.

CONCLUSIONS

The clinical accuracy error was similar when using generic and licensed orthodontic software for guided systems.

Airway dimensional changes following bone anchored maxillary protraction: a systematic review

BACKGROUND

The introduction of skeletal anchorage utilized for maxillary protraction with a face mask or class III elastics has been developed for the management of class III malocclusions with minimal dental effect. The objective of the present review was to evaluate the current evidence regarding airway dimensional changes following bone-anchored maxillary protraction. A search was conducted by two authors (S.A & B.A) in the following databases: MEDLINE via PubMed, Cochrane Library, Web of Science, Scopus, Google Scholar and Open Grey; besides a hand search in references of selected articles and developing a search alert in electronic databases. Selection criteria comprised randomized as well as prospective clinical trials evaluating airway dimensional changes following bone-anchored maxillary protraction. Relevant data were extracted after studies retrieval and selection. The risk of bias was thereafter evaluated using the revised RoB 2 tool for randomized clinical trials and the ROBINS-I tool was used for non-randomized clinical trials. The quality of studies was assessed using the modified Jadad score. After examining (eligibility) full-text articles, four clinical trials were ultimately included. These studies evaluated the airway dimensional changes, following bone-anchored maxillary protraction in comparison to different control study groups. Based on the available evidence, all the bone-anchored maxillary protraction devices used in the eligible studies in the present systematic review resulted in an improvement in the airway dimensions. However, due to the few numbers of studies available and the guarded evidence due to the low quality of evidence of three out of four included articles, there is no strong evidence to support a significant increase in the airway dimensions following bone-anchored maxillary protraction. Therefore, there is a need for more randomized controlled clinical trials with similar bone-anchored protraction devices and similar assessment methods for more valid comparisons, excluding any confounding factors, on airway dimensional changes.

Mini-implant assisted posterior intrusion: A quantification of anterior bite closure in nongrowing subjects

INTRODUCTION

This study aimed to identify the vertical radiographic changes in nongrowing patients after treatment of anterior open bites (AOBs) using mini-implant assisted intrusion and to provide a predictive model to quantify the achievable intrusion.

METHODS

This retrospective radiographic study evaluated the dentoskeletal changes in adults using orthodontic mini-implants in 53 treated patients with AOB. Radiographs before and after posterior intrusion were utilized to evaluate the associated changes. Conventional cephalometric analyses provided data for assessment. A paired t test was used to identify significant changes. A regression model (best subsets selection algorithm) was generated to quantify the relationship between mini-implant-assisted intrusion and the resultant change in overbite. A matched, untreated control sample was used for comparison.

RESULTS

One hundred percent of AOBs were corrected using mini-implant-assisted intrusion of the maxillary molars. The overbite increased by an average of 3.6 mm. The average amount of maxillary first molar intrusion was 2.67 mm. The mandibular first molar moved an average of 1.93 mm closer to the palatal plane because of an average clockwise mandibular rotation of 0.78°. The occlusal plane steepened by an average of 3.95°. If all other inputs are held constant, 1 mm of intrusion of the maxillary first molar results in a 0.86 mm increase in overbite.

CONCLUSIONS

Mini-implant-assisted intrusion successfully treated AOB in adults with significant dentoalveolar but no significant skeletal changes. An average of 2.67 mm of intrusion of the maxillary first molars is achievable with this method showing that 1 mm of intrusion of the maxillary first molar increased overbite by 0.86 mm. Longer periods of intrusion resulted in greater amounts of bite closure.

Rate of upper incisor retraction in Class II division 1 patients managed with palatal versus buccal miniscrew supported segmental orthodontics: Randomized parallel clinical trial

OBJECTIVE

This study was conducted to compare maxillary incisor retraction rates using buccal orthodontics with segmented arch approach supported by a buccal or palatal mini-screw in non-growing Class II Division 1 patients during a 3-month period.

PATIENTS AND METHODS

All patients between September 2018 and December 2021 with following criteria were included: non-growing class II division 1 protrusion, indication for premolar extraction, no or little crowding, normal overbite, no previous orthodontic treatment, no systematic disease, good oral hygiene, no periodontal problems or oral habits. Mini-implant was inserted buccally or palatally between upper second premolar and first molar bilaterally. Incisor retraction was manipulated by a 200-gram force through a nickel-titanium closed-coil spring extended from the mini-implant to the segmental design. Study casts were made before retraction and after every 4 weeks (T0: baseline, T1: 4 weeks, T2, 8 weeks, T3: 12 weeks). A repeated measures ANOVA was performed for total comparison of data (mm of retraction) on 3D casts. A pairwise t test with Bonferroni correction was used for comparison between two experimental periods for the same group. An independent samples t-test was also used for comparison between two groups for the same experimental period.

RESULTS

Of 30 patients meeting the eligibility criteria, only 28 were included with mean age 16±2.5 years. Repeated measures ANOVA revealed significant differences in incisor retraction between the time intervals for both buccal and palatal groups (P=0.001). In addition, the paired-sample t test indicated a significant difference between each time interval for both the buccal and palatal groups (P=0.001), except between T3 and T2 for the palatal group (P=0.09). The independent sample t-test revealed significant differences between the buccal and palatal groups at T1 (Mean: 0.55 [0.355-0.748],=0.001) and T2 (Mean: 1.4 [0.91-1.88], P=0.001); whereas no significant difference was found at T3 (Mean: 1.15 [0.67-1.63], P=0.945).

CONCLUSIONS

Anterior retraction using a segmental palatal model with mini-screws was effective regardless of the buccal or palatal situation of the minivis. Retraction of incisors with palatal miniscrews was significantly faster in the first two months.

Effect of thread depth and thread pitch on the primary stability of miniscrews receiving a torque load : A finite element analysis

PURPOSE

We have been developing a new type of miniscrew to specifically withstand orthodontic torque load. This study aimed to investigate the effect of thread depth and thread pitch on the primary stability of these miniscrews if stressed with torque load.

METHODS

Finite element analysis (FEA) was used to evaluate the primary stability of the miniscrews. For thread depth analysis, the thread depth was set to 0.1-0.4 mm to construct 7 models. For thread pitch analysis, the thread pitch was set to 0.4-1.0 mm to construct another 7 models. A torque load of 6 Nmm was applied to the miniscrew, and the other parameters were kept constant for the analyses. Maximum equivalent stress (Max EQV) of cortical bone and maximum displacement of the miniscrews (Max DM) were the indicators for primary stability of the miniscrew in the 14 models.

RESULTS

In the thread depth analysis, Max DM increased as the miniscrew thread depth increased, while Max EQV was smallest in model 3 (thread depth = 0.2, Max EQV = 8.91 MPa). In the pitch analysis, with an increase of the thread pitch, Max DM generally exhibited a trend to increase, while Max EQV of cortical bone showed a general trend to decrease.

CONCLUSION

Considering the data of Max DM and Max EQV, the most appropriate thread depth and thread pitch of the miniscrews in our model was 0.2 and 0.7 mm, respectively. This knowledge may effectively improve the primary stability of newly developed miniscrews.

Identification of Senescent Cells in Peri-Implantitis and Prevention of Mini-Implant Loss Using Senolytics

Peri-implantitis is a disease that causes the detachment of orthodontic mini-implants. Recently, stress-induced senescent cells have been reported to be involved in various inflammatory diseases. Senescent cell-eliminating drugs, termed "senolytics", can improve the symptoms of such diseases. However, the relationship between peri-implantitis and senescent cells remains unclear. In this study, we evaluated the presence of senescent cells in a rat peri-implantitis model developed with a gum ring. The effect on bone resorption and implant loss was also investigated with and without senolytics (Dasatinib and Quercetin). The number of senescence markers (p19, p21, and p16) was found to increase, and implant detachment occurred in 24 days. After the administration of senolytics, the number of senescence markers decreased and implant detachment was inhibited. This study suggests that senescent cells aggravate peri-implantitis and senolytic administration latently reduces implant loss by inhibiting senescence-related mechanisms.

Minimum volume of infiltrative anesthetic required for pain-free placement of mini-implants: a split-mouth clinical trial

OBJECTIVE

To determine the minimum volume of infiltrative anesthetic required for pain-free mini-implant placement in the maxillary buccal region by comparing the efficacy of 1.0 mL with 0.5 mL of 2% lignocaine with 1:200,000 epinephrine during mini-implant placement.

METHOD AND MATERIALS

This split-mouth study involved 19 healthy patients without systemic disease, recent history of allergy, or medications within the age group of 17 to 28 years belonging to both sexes requiring bilateral buccal mini-implants in the posterior maxilla. Lignocaine 2% with 1:200,000 epinephrine (0.5 mL and 1.0 mL) was randomly injected between the right and left side 30 minutes apart for each consecutive patient. Mini-implants were placed 5 minutes after the administration of the infiltrative anesthetic. The pain response was evaluated during mini-implant placement (T1), and 5 minutes (T2) and 10 minutes (T3) after mini-implant placement on both sides using a pain-rating scale. Descriptive statistics and a factorial repeated-measure analysis of variance were calculated for pain response, sex, and side of the jaw.

RESULTS

At T1, T2, and T3, 1.0 mL of anesthetic had a lesser pain score by 1.00, 1.00, and 0.58, respectively, compared to 0.5 mL, with 95% confidence intervals of 0.43 to 1.57 (P = .001), 0.49 to 1.51 (P = .000), and 0.08 to 1.08 (P = .024), respectively.

CONCLUSIONS

1.0 mL of 2% lignocaine with 1:200,000 epinephrine administered submucosally appears to provide better anesthesia than 0.5 mL during and after insertion of mini-implants. This study will help the operator administer the correct volume of infiltrative anesthetic thereby improving pain response, alleviating patient anxiety, and providing a better patient experience during and immediately after mini-implant placement.

Accuracy of palatal orthodontic mini-implants placed by conventionally or CAD/CAM-based surgical guides: a comparative in vitro study

OBJECTIVES

To investigate and compare the transfer accuracy of five different surgical guides (SGs) for the insertion of orthodontic mini-implants (OMIs) in the anterior palate.

MATERIALS AND METHODS

Stereolithographic files of 10 maxillary patient models and their corresponding lateral cephalograms were virtually matched and used for planning the position of two parallel OMIs in the paramedian region of the anterior palate. For each patient model, three 3-dimensional (3D)-printed and two conventional SGs were manufactured from different materials, and a total of 96 OMIs were transferred to the anterior palates of the respective 50 molded resin models. The planned (T0) and the actual (T1) OMI positions were analyzed and compared after superimposition of the digitized models. The deviations between the OMI positions in T0 and T1 were described as the distance between the head and the tip, respectively, of each OMI in millimeters and the deviating angle between the OMI axes for each patient and SG.

RESULTS

The conventionally manufactured SGs of Pattern Resin LS (GC Europe N.V., Leuven, Belgium) showed the highest linear and angular transfer accuracy for the insertion of OMIs. The highest deviations were found with the SGs made of IMPRIMO LC Splint (3D-printed; Scheu-Dental, Iserlohn, Germany) and Memosil 2 (conventional SG; Kulzer, Hanau, Germany).

CONCLUSIONS

The 3D-printed SGs did not reach the accuracy of the conventional SGs made of Pattern Resin but may provide sufficient accuracy for palatal OMI placement.

Total arch maxillary distalization using infrazygomatic crest miniscrews in the treatment of Class II malocclusion: a prospective study

OBJECTIVES

To evaluate treatment effects in Class II patients using infrazygomatic crest (IZC) miniscrews (MS).

MATERIALS AND METHODS

A prospective sample of 25 adolescents (14 females and 11 males; mean age: 13.6 ± 1.5 years) who underwent maxillary dentition distalization treatment with IZC MSs were recruited. Lateral cephalograms and digital models at the beginning of treatment (T1) and after Class II molar correction (T2) were obtained. To compare cephalometric and digital model changes, paired t-test and Wilcoxon test were used. A significance level of 5% was used.

RESULTS

All patients achieved Class II molar correction over a mean period of 7.7 ± 2.5 months. The IZC MS therapy provided 4 mm of distalization; there was 1.2 mm of intrusion of the first molar with 11.2° distal tipping. The maxillary incisors were retracted 4.7 mm and tipped lingually 13.4°. Overjet and overbite showed a reduction of 3.6 mm and 2.4 mm, respectively. The occlusal plane rotated clockwise 2.8°. The upper lip was retracted by 1 mm and the nasolabial angle increased 5.1°. There was an increase in the interpremolar and intermolar distances.

CONCLUSIONS

Total arch distalization of the maxillary dentition using IZC MS was effective in the treatment of Class II malocclusions.

A novel auxiliary device enhances miniscrew stability under immediate heavy loading simulating orthopedic treatment

OBJECTIVES

To evaluate miniscrew stability and perform a histomorphometric analysis of the bone around the miniscrew under a load corresponding to orthopedic force.

MATERIALS AND METHODS

Thirty-two miniscrews were implanted into eight rabbit tibias. Auxiliary group rabbits received auxiliary devices with miniscrews (n = 8, 28 days; n = 8, 56 days), and those in the nonauxiliary control group received miniscrews without auxiliary devices (n = 8, 28 days; n = 8, 56 days). Elastics were placed between miniscrews to apply a load of 5 N. Miniscrew stability was evaluated using a Periotest. Bone-to-implant contact (BIC) and spike implantation depth were measured histomorphologically.

RESULTS

Periotest values in the auxiliary group were significantly lower than those in the nonauxiliary group at all time periods. There was no significant difference in BIC between the auxiliary and nonauxiliary groups at 28 or 56 days postimplantation. The implantation spike depth in the auxiliary group was significantly greater at 56 days compared to that at 28 days. Newly formed bone was observed around the spike of the auxiliary device at 56 days.

CONCLUSIONS

The results suggest that the use of miniscrews in conjunction with auxiliary devices provides stable skeletal anchorage, which may be useful in orthopedic treatments.

Bi-maxillary Protrusion: An Orthodontic Management

Bi-maxillary protrusion is a condition with protrusive and proclined upper and lower incisors and the patient is not able to close lips without strain. The presented case reported with the chief complaint of forwardly placed teeth, with skeletal class II malocclusion, and Angle's class I malocclusion with protrusive and forwardly placed upper and lower incisors. The treatment was performed with the extraction of all first premolars and retraction under absolute anchorage. The retraction of upper and lower lips of about 3 mm and 3.5 mm was achieved respectively and the patient was able to close lips without strain. With proper anchorage preparation, bi-maxillary protrusion can be successfully managed orthodontically.

Evaluation of the rate of anterior segment retraction in orthodontic patients with bimaxillary protrusion using friction vs frictionless mechanics

OBJECTIVES

To evaluate the effect of friction vs frictionless mechanics on the rate of anterior segment retraction (ASR) in patients with bimaxillary protrusion.

MATERIALS AND METHODS

Thirty females (18.3 ± 3.7 years) with bimaxillary protrusion were randomly allocated into the friction group, using elastomeric power chains, and the frictionless group, using T-loop springs for ASR. Eligibility criteria included absence of skeletal discrepancies and any systemic diseases or medications, among others. Randomization in a 1:1 ratio was generated by Microsoft Excel. Opaque sealed envelopes were sequentially numbered for allocation concealment. Only blinding of the outcome assessor was applicable. Activations were done every 4 weeks until completion of ASR. The primary outcome was the rate of ASR measured on digital models. Anchorage loss, molar rotation, and pain experienced were also assessed.

RESULTS

Two patients were lost to follow-up. The rate of ASR was 0.68 ± 0.18 mm/mo in the friction group vs 0.88 ± 0.27 mm/mo in the frictionless group, with no significant difference. A significant difference in anchorage loss of 1.63 mm and molar rotation of 7.06° was observed, being higher in the frictionless group. A comparable pain experience associated with both mechanics was reported.

CONCLUSIONS

No difference in the rate of ASR or pain experience was observed between friction and frictionless mechanics. However, extra anchorage measures should be considered when using frictionless mechanics as greater anchorage loss and molar rotations are anticipated.

Skeletal and dentoalveolar effects of class II malocclusion treatment using bi-maxillary skeletal anchorage: a systematic review

BACKGROUND

The goal of this systematic review was to assess the available evidence regarding the skeletal and dentoalveolar effects of bi-maxillary skeletal anchorage devices (BMSADs) used in treating growing class II malocclusion patients.

METHODS

A comprehensive search was conducted on PubMed, Scopus, Science Direct, Web of Science, Cochrane, and LILACS up to November 2021, which was augmented by a manual search. The studies included were clinical trials (RCTs) and/or follow-up observational studies (retrospective and prospective). The outcomes of interest were the skeletal, dentoalveolar, and occlusal treatment-induced changes obtained from pre- and post-cephalometric measurements. The risks of bias of the included studies were assessed using an assessment tool from previous publications.

RESULTS

Out of 742 screened articles, only 4 were eligible and thus included in the qualitative synthesis. They showed a moderate overall risk of bias. The results are presented as mean changes in both the study and control groups. All studies reported retrusion of the maxillary base and advancement of the mandible (meaning reduced ANB angle). Three of the included studies reported an increase in the vertical jaw relation, which was contrary to what the fourth study reported. Three studies reported an increase in the maxillary incisors' inclination or position, while one study reported their retroclination. Proclination of the mandibular incisors happened in two studies, whereas the other two studies reported retroclination. The overjet was reduced in all included studies.

CONCLUSION

Apart from the protrusive effects on the mandible, retrusive effects on the maxilla, and the consequent reduction of the overjet, BMSADs results in inconsistent skeletal and dentoalveolar effects. However, the current evidence is limited due to the variability in the biomechanics of the intermaxillary components, type of anchorage, and comparable groups in the included studies. Further RCTs with more standardized methodologies are highly encouraged.

CLINICAL RELEVANCE

BMSADs (using miniscrews or miniplates on both jaws) induces more skeletal than dentoalveolar effects. However, this must be practiced with caution, based on the benefit to risk (surgical insertion) ratio, and the limited evidence available in hand so far. Registration The protocol for this systematic review was registered at the International Prospective Register of Systematic Reviews (PROSPERO, No.: CRD42020199601).

Treatment effects of maxillary protraction with palatal plates vs conventional tooth-borne anchorage in growing patients with Class III malocclusion

INTRODUCTION

Evaluate the treatment effects of maxillary protraction using palatal plates and compare them to those with conventional tooth-borne anchorage in growing patients with Class III malocclusion.

METHODS

Forty patients were divided into 2 groups according to the type of anchorage used: group 1 (n = 20; mean age, 10.5 ± 1.6 years; palatal plates) and group 2 (n = 20; mean age, 10.0 ± 1.2 years; tooth-borne appliances). Lateral cephalograms were taken before and after maxillary protraction. Skeletal, dental, and soft-tissue variables were measured. For statistical analysis, paired and independent t tests were performed.

RESULTS

Group 1 showed maxilla advancement by 2.3 ± 1.0 mm compared with group 2 by 0.9 ± 0.6 mm, and group 2 indicated clockwise rotation of the mandible, but there was no such clockwise rotation in group 1 (P <0.001). Group 1 had a less lingual inclination of the mandibular incisors than group 2 (IMPA, -1.0° ± 3.8° vs -3.8° ± 2.8°; P <0.05). There was no difference in soft-tissue changes between the 2 groups.

CONCLUSIONS

A facemask with palatal plate induced maxillary advancement with less mandibular clockwise rotation and dental movement than conventional tooth-borne anchorage. This modality can be used efficiently for maxillary protraction in growing patients with Class III malocclusion.

Torque control of maxillary anterior teeth with the double J retractor and palatal miniscrews during en masse retraction

A double J retractor (DJR) and palatal miniscrews were used to retract maxillary anterior teeth after failure of buccal posterior miniscrews. The line of action passing through the center of resistance of the maxillary anterior teeth and the moment generated by the palatal miniscrews via torquing springs successfully controlled the overbite and incisor torque during space closure. The DJR and palatal miniscrews work well with labial fixed appliances to address bimaxillary protrusion.

Evaluation of bone depth, cortical bone, and mucosa thickness of palatal posterior supra-alveolar insertion site for miniscrew placement

BACKGROUND

The use of palatal miniscrew offers the possibility to improve the effectiveness of orthodontic expansion devices. Palatal expanders supported by miniscrew can be applied with different clinical protocols. Some authors proposed the use of four palatal miniscrews during miniscrew-supported palatal expansion to maximize skeletal effects in young adults' treatment. However, bone availability decreases in the posterior paramedian palatal regions, making the positioning of the two-posterior paramedian palatal miniscrews challenging, when it is performed avoiding nasal cavities invasion. Some authors proposed miniscrews insertion in a specific region located laterally to the palatal process of the maxillary bone, and apically relatively to the dento-alveolar process. The aim of this study was to evaluate the bone thickness, cortical bone thickness, and mucosae depth of this anatomical site that, in this study, was defined as palatal posterior supra-alveolar insertion site.

RESULTS

The evaluation of bone availability of palatal posterior supra-alveolar insertion site at different antero-posterior levels showed that the maximum amount of total bone thickness was found between the second premolar and the first molar. At this level total bone, thickness is significantly (p < .05) greater compared to the other sagittal sites and it offers on average around 2 mm of extra bone depth for miniscrew placement. Cortical bone thickness is adequate for primary miniscrew stability. Overall, cortical bone thickness considered at different insertion sites showed significant statistically (p < .05) differences. The findings of this study showed that palatal mucosa is particularly thick with average values ranging from 4 to 7 mm, and its extension ultimately affects miniscrew length selection. Palatal mucosa thickness showed no clinically significant differences comparing different sagittal and vertical insertion sites. Data also showed that palatal mucosal thickness slightly significantly increases (p < .05) with the inclination of the insertion axis relative to the occlusal plane. Finally, study findings showed that vertical growth pattern can significantly affect considered outcomes (p < .05).

CONCLUSIONS

Palatal posterior supra-alveolar insertion site is an appropriate site for posterior insertion of palatal miniscrews. Considering high anatomical variation preliminary CBCT evaluation is important to achieve optimal miniscrew placement.