Bone cutting capacity and osseointegration of surface-treated orthodontic mini-implants

Survival rate and stability of surface-treated and non-surface-treated orthodontic mini-implants: a randomized clinical trial

OBJECTIVES

This clinical trial was conducted to evaluate the stability and failure rate of surface-treated orthodontic mini-implants and determine whether they differ from those of non-surface-treated orthodontic mini-implants.

TRIAL DESIGN

Randomized clinical trial with a split-mouth study design.

SETTING

Department of Orthodontics, SRM Dental College, Chennai.

PARTICIPANTS

Patients who required orthodontic mini-implants for anterior retraction in both arches.

METHODS

Self-drilling, tapered, titanium orthodontic mini-implants with and without surface treatment were placed in each patient following a split-mouth design. The maximum insertion and removal torques were measured for each implant using a digital torque driver. The failure rates were calculated for each type of mini-implant.

RESULTS

The mean maximum insertion torque was 17.9 ± 5.6 Ncm for surface-treated mini-implants and 16.4 ± 9.0 Ncm for non-surface-treated mini-implants. The mean maximum removal torque was 8.1 ± 2.9 Ncm for surface-treated mini-implants and 3.3 ± 1.9 Ncm for non-surface-treated mini-implants. Among the failed implants, 71.4% were non-surface-treated mini-implants and 28.6% were surface-treated mini-implants.

CONCLUSION

The insertion torque and failure rate did not differ significantly between the groups, whereas the removal torque was significantly higher in the surface-treated group. Thus, surface treatment using sandblasting and acid etching may improve the secondary stability of self-drilling orthodontic mini-implants.

TRIAL REGISTRATION

The trial was registered in the Clinical Trials Registry, India (ICMR NIMS). Registration number: CTRI/2019/10/021718.

Comparison of Biomechanical Properties of Surface-Treated and Untreated Machined Orthodontic Mini-Implants: An In Vitro Study

Background and Objectives:

The use of mini-implants has become more popular, and there has been a heightened focus on factors that contribute to their success. The purpose of the study is to compare the effects of various surface treatment methods of mini-implants on their bone cutting capacity, insertion torque required, and fracture resistance when compared with the untreated machined mini-implants.

Materials and Methods:

The study included 4 groups. Each group consisted of 10 orthodontic mini-implants (OMIs). The first experimental group contains titanium oxide coated mini-implants, the second group contains grit-blasted implants with aluminum oxide, the third group consists of mini-implants coated with hydroxyapatite crystals, and the control group is formed by untreated machined mini-implants. Each group is evaluated for cutting efficiency, maximum insertion torque, and fracture resistance using a customized torque testing gauge.

Results:

The results showed that surface treating OMIs with hydroxyapatite particles increases the surface roughness, thereby enhancing their stability without decreasing the bone cutting ability compared with OMIs without surface treatment.

Conclusion:

Roughened surface of OMIs with hydroxyapatite particles exhibited maximum fracture resistance without decreased corresponding bone cutting efficiency.

Success rate of surface-treated and non-treated orthodontic miniscrews as anchorage reinforcement in the lower arch for the Herbst appliance: A single-centre, randomised split-mouth clinical trial

BACKGROUND

Surface treatment of miniscrews was implemented to determine whether its application increased bone-to-surface contact and enhanced the interlock between the device and the surrounding bone.

OBJECTIVES

To compare the success rate of surface-treated and non-treated orthodontic miniscrews used as reinforcement of anchorage during treatment with the Herbst appliance.

TRIAL DESIGN

Split-mouth design with an allocation ratio of 1:1.

METHODS

Eligibility criteria to enrol patients were skeletal and dental class II patients with a retrusive chin, use of the Herbst appliance to correct malocclusion, need for skeletal anchorage using a miniscrew both in the left and right side of the mouth, absence of systemic diseases, absence of using drugs that alter bone metabolism, and good oral hygiene. Patients received self-drilling miniscrews without surface treatment and with surface treatment. Both types presented a 1.4 or 1.2 mm diameter. Miniscrews were inserted between the first molar and second premolars or between the two premolars. The force applied to the screws was an elastic chain from the head of the miniscrews to a direct button applied on the canines. The success rate of each type of miniscrew was considered the primary outcome, and the association of success with demographical, clinical, and geometrical characteristics was investigated. Differences were tested by the generalised linear mixed effects model for the split-mouth design. Differences with a P-value < 0.05 were selected as significant.

RANDOMISATION

A randomisation list was created for the mouth side assignment.

BLINDING

The study was single blinded with regard to the statistical analysis.

RESULTS

Thirty-nine miniscrews of the non-treated type and 39 miniscrews of the surface-treated type were inserted in 39 patients (23 female and 16 male, mean age: 15.55 ± 7.91) recruited between March 2018 and December 2020 with a split-mouth study design. The mean therapy duration was 9.3 months (SD = 1.31). No differences in failure rate were observed between miniscrew types. No serious harm was observed.

CONCLUSIONS

The success rate of surface-treated and non-treated miniscrews showed no significant differences.

REGISTRATION

This trial was not registered.

Effect of surface treatment on the mechanical stability of orthodontic miniscrews

OBJECTIVES

To provide collective quantitative evidence about the effect of surface treatments on the mechanical stability of orthodontic miniscrews (MSs).

MATERIALS AND METHODS

The study was registered in PROSPERO (No. CRD42020209652). The research question was defined according to the PICO (population, intervention, control, and outcomes) format. Various research databases were searched for animal and human studies on effects of surface treatment on the mechanical stability of MSs. Both prospective and retrospective in vivo clinical studies published in English were included. The risk of bias was assessed using SYRCLE's risk of bias tool for animal studies. The meta-analysis was conducted using RevMan 5.4.

RESULTS

A total of 109 articles were identified; 14 were included in the systematic review, and seven studies with sandblasting, acid etching (SLA) methods of surface treatment were included for meta-analysis. The number of study participants ranged from 6 to 24 (total n = 185), with a mean of 13.2. A total of 949 MSs were used with a mean of 67.8. The overall success rate for surface-treated MSs ranged from 47.9% to 100%. Forest plot of removal torque values showed significantly higher values for SLA surface-treated MSs compared with controls with a standard mean difference of 2.61 (95% confidence interval = 1.49-3.72, I2 = 85%). Forest plot of insertion torque showed a standard mean difference of -6.19 (95% confidence interval = -13.63-1.25, I2 = 98%, P = .10).

CONCLUSIONS

Surface treatment of MSs improved primary and secondary stability with good osseointegration at the bone-implant surface. However, significant heterogeneity across the studies included in the meta-analysis made it difficult to draw conclusions.

The effect of sandblasting and acid etching on survival rate of orthodontic miniscrews: a split-mouth randomized controlled trial

Background

The aim of this study was to investigate the effect of surface roughening and acid etching on clinical success rate and removal and insertion torque of orthodontic miniscrews.

Materials and methods

Sixty-two orthodontic miniscrews (Jail Medical Corporation, Seoul, Korea) with the same design and dimensions (10-mm length, 2-mm diameter) are divided into two (sandblasted and acid-etched versus control) groups. The sample of the study was 31 patients whose miniscrews were needed for en masse retraction of the upper six anterior teeth. In this split-mouth study, the miniscrews were placed in the attached gingiva between the second premolar and the first molar. The side (left or right) was selected randomly. The miniscrews were loaded 6 weeks after insertion, and the patients were followed up after 3, 6, 10, 14, and 18 weeks and then for 4 weeks interval. Chi-square, correlation, and independent t tests were done using SPSS ver24 to interpret the data.

Results

The survival rate was 90.3% and 83.9% for the sandblasted and acid-etched versus the control group, respectively. The difference in survival rate was not statistically significant (p > 0.05). Removal torque was higher for the sandblasted group (p < 0.05). Younger patients showed less survival rate (p < 0.05) in both groups. Insertion side, namely, left or right, was not statistically significant.

Conclusions

Although sandblasting increased removal torque, it did not influence the survival rate of orthodontic miniscrews significantly.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40510-020-00347-z.

Maximum insertion torque loss after miniscrew placement in orthodontic patients: A randomized controlled trial

OBJECTIVES

To compare torque recordings of immediately loaded orthodontic miniscrews between insertion time and different post-placement timepoints (2 weeks, 4 weeks and removal time, respectively).

SETTING AND SAMPLE POPULATION

Parallel trial with an allocation ratio of 1:1. Eligibility criteria were needs of fixed orthodontic treatment, no systemic disease and absence of using drugs altering bone metabolism.

MATERIAL AND METHODS

Patients received miniscrews, 2.0 mm diameter and 10 mm length. All miniscrews underwent inter-radicular placement, and they were placed in the maxilla or in the mandible, palatally or buccally. No pre-drilling was performed. Miniscrews were loaded immediately after the insertion and were used for distalization, intrusion, extrusion, mesialization or indirect anchorage. Patients were randomly divided into three groups. For each patient, Maximum Insertion Torque (MIT) was evaluated at baseline. MIT was measured again after 2 weeks and after 4 weeks by tightening the screw a quarter of turn in Groups 1 and 2, respectively. At the end of the treatment, maximal removal torque was evaluated in Group 3. Torque variation with respect to insertion time was considered as the primary outcome. Baseline and longitudinal differences were tested using the linear mixed-effects (LME) model.

RESULTS

Forty seven patients and 74 miniscrews were followed up. An association existed between maximum insertion torque and the observation time. A torque decrease of 26.9% and 30% after 2 weeks was observed for mandibular and maxillary miniscrews, respectively. After 1 month, torque values were similar to the baseline records. The overall success rate was 79.7%. No serious harm was observed.

CONCLUSIONS

Maximum insertion torque undergoes a loss during the first 2 weeks, and its values may depend on the insertion site and the anchorage purpose. Removal torque value is almost the same as the initial torque after 1 month.

Mini implants osseointegration, molar intrusion and root resorption in Sinclair minipigs

AIM

The use of mini implants to create a passive intraoral anchorage point has been mainly tested in clinical trials. In this study, an experimental integrated approach evaluated mini implant loading protocols (immediate vs. delayed loading) on bone remodelling and mini implant stability and the consequent degree of dental intrusion and apical root resorption.

METHODS

A total of 40 Absoanchor® mini implants with 1.2mm diameter and 8mm length were placed in a total of 5 minipigs, 8 per animal, 2 in each hemiarch. Each implant was attached through a lingual button to the vestibular side of the second and fourth premolars with a nitinol coil spring of 150g force. The analysis of morphological aspects included the degree of dental movement, mini implant stability, and new bone formation over the mini implant heads. Bone mini-implant interface and modifications of dental root in response to intrusion were studied by light and electron microscopy.

RESULTS

The rate of mini implant success was>98%, mainly in those subjected to immediate loading. This loading protocol promoted a high degree of osseointegration along with a high degree of intrusive dental movement, particularly of the second premolars. However, the radiological and histological studies showed a low degree of root resorption. Associated with the high intrusive movement, the penetration of the root apexes produced an inner cortical surface deformation of the maxillary sinus floor by remodeling and bone growth.

CONCLUSION

In minipigs immediate loading of smooth mini implants promoted a high degree of intrusive movement particularly of the second premolars, stimulated bone growth and osseointegration, but extensive root resorption was not observed.

Repeated injections of botulinum toxin into the masseter muscle induce bony changes in human adults: A longitudinal study

OBJECTIVE

To evaluate soft- and hard-tissue changes in the mandibular angle area after the administration of botulinum toxin type A (BoNT-A) injection to patients with masseteric hypertrophy by using three-dimensional cone-beam computed tomography (3D-CBCT).

METHODS

Twenty volunteers were randomly divided into two groups of 10 patients. Patients in group I received a single BoNT-A injection in both masseter muscles, while those in group II received two BoNT-A injections in each masseter muscle, with the second injection being administered 4 months after the first one. In both groups, 3D-CBCT was performed before the first injection and 6 months after the first injection.

RESULTS

Masseter muscle thicknesses and cross-sectional areas were significantly reduced in both groups, but the reductions were significantly more substantial in group II than in group I. The intergonial width of the mandibular angle area did not change significantly in either group. However, the bone volume of the mandibular gonial angle area was more significantly reduced in group II than in group I.

CONCLUSIONS

The repeated administration of BoNT-A injections may induce bone volume changes in the mandibular angle area.