[Three-dimensional printed miniplate used for maxillary protraction]

The miniplate was designed and three-dimensional (3D) printed according to the positions of roots and tooth germs and then it was used as skeletal anchorage to protract the maxilla. The maxilla moved forward obviously after treatment. Custom designed and 3D printed miniplate could be used for maxillary protraction.

Success rates of a skeletal anchorage system in orthodontics: A retrospective analysis

OBJECTIVES

To evaluate the premise that skeletal anchorage with SAS miniplates are highly successful and predictable for a range of complex orthodontic movements.

MATERIALS AND METHODS

This retrospective cross-sectional analysis consisted of 421 bone plates placed by one clinician in 163 patients (95 female, 68 male, mean age 29.4 years ± 12.02). Simple descriptive statistics were performed for a wide range of malocclusions and desired movements to obtain success, complication, and failure rates.

RESULTS

The success rate of skeletal anchorage system miniplates was 98.6%, where approximately 40% of cases experienced mild complications. The most common complication was soft tissue inflammation, which was amenable to focused oral hygiene and antiseptic rinses. Infection occurred in approximately 15% of patients where there was a statistically significant correlation with poor oral hygiene. The most common movements were distalization and intrusion of teeth. More than a third of the cases involved complex movements in more than one plane of space.

CONCLUSIONS

The success rate of skeletal anchorage system miniplates is high and predictable for a wide range of complex orthodontic movements.

Bone availability for mandibular molar distalization in adults with mandibular prognathism

OBJECTIVES

To investigate the retromolar space available for molar distalization in patients with mandibular prognathism.

MATERIALS AND METHODS

Using cone-beam computed tomography, the posterior mandibular dimensions in 110 consecutive patients with Class I or Class III malocclusion were measured (mean age, 27.0 ± 7.1 years). The shortest linear distances from the distal root of the right mandibular second molar to the inner border of the mandibular cortex were measured at the level of root furcation and 2, 4, and 6 mm apical to the furcation along the sagittal line and the posterior line of occlusion. The retromolar distances were compared between the Class I and Class III malocclusion groups using general linear mixed models.

RESULTS

The retromolar space measured through the sagittal line showed no significant intergroup difference. Among the distances measured through the posterior line of occlusion, the space measured at depths 0 and 2 mm to the furcation were significantly greater in the Class III group than in the Class I group.

CONCLUSIONS

Patients with Class III malocclusion have greater retromolar space for mandibular molar distalization along the posterior line of occlusion only at the level of the second molar furcation.

Treatment outcomes of Class II malocclusion cases treated with miniscrew-anchored Forsus Fatigue Resistant Device: A randomized controlled trial

OBJECTIVE

To evaluate the skeletal, dental, and soft tissue effects of the Forsus Fatigue Resistant Device (FRD) used with miniscrew anchorage and compare them with those of the conventional Forsus FRD.

MATERIALS AND METHODS

This study was carried out on 38 patients. These patients were randomly allocated into three groups. The 14 patients in group 1 (aged 12.76 ± 1.0 years) were treated with the FRD appliance. In group 2, the 15 patients (aged 12.52 ± 1.12 years) received treatment with FRD using miniscrew anchorage, and the 9 patients in group 3 (aged 12.82 ± 0.9 years) received no treatment as a control group. Linear and angular measurements were made on lateral cephalograms before and immediately after Forsus treatment. Data were analyzed statistically using paired t-, ANOVA, and Tukey tests.

RESULTS

Class I molar relationship and overjet correction were achieved in both treatment groups. Although mandibular growth was statistically nonsignificant, there was a significant headgear effect on the maxilla. Mandibular incisor proclination, maxillary incisor retroclination, and distalization of maxillary molars were significant in both treatment groups. However, no significant differences were found between the treatment groups.

CONCLUSIONS

Class II correction was mainly dentoalveolar in both treatment groups. Use of miniscrews with Forsus did not enhance mandibular forward growth nor prevent labial tipping of the mandibular incisors.

Anatomic landmarks and availability of bone for placement of orthodontic mini-implants for normal and short maxillary body lengths

INTRODUCTION

Increasing numbers of orthodontic mini-implants are placed in the anterior maxilla. To our knowledge, bone levels and root proximity of patients with cephalometrically short maxillae have not been investigated before. The first, second, and third rugae were used as clinical reference lines, and the aim of this study was to measure bone availability in that area by comparing patients with short and normal maxillary body lengths.

METHODS

The sample consisted of 21 patients in each group: short maxillary body length and normal maxillary body length. The patients' study models were bisected, and the outline of the palatal contour was marked on the surface. The models were scanned, and the palatal contours were superimposed on the palatal structures of their respective initial cephalometric headfilms, and the vertical and oblique bone levels of the sagittal plane were compared using the Student t test. The level of significance was set at P <0.05.

RESULTS

Compared with maxillae of normal maxillary body length, less bone was available in maxillae of short maxillary body length. However, the differences did not reach clinical or statistical significance (P >0.05) at the third rugae.

CONCLUSIONS

Almost equivalent average bone depth at the third rugae in patients with normal and short maxillary body lengths suggests that this site can be used for 8-mm long obliquely inserted orthodontic mini-implants.

Biomechanical Effects of Various Bone-Implant Interfaces on the Stability of Orthodontic Miniscrews: A Finite Element Study

INTRODUCTION

Osseointegration is required for prosthetic implant, but the various bone-implant interfaces of orthodontic miniscrews would be a great interest for the orthodontist. There is no clear consensus regarding the minimum amount of bone-implant osseointegration required for a stable miniscrew. The objective of this study was to investigate the influence of different bone-implant interfaces on the miniscrew and its surrounding tissue.

METHODS

Using finite element analysis, an advanced approach representing the bone-implant interface is adopted herein, and different degrees of bone-implant osseointegration were implemented in the FE models. A total of 26 different FE analyses were performed. The stress/strain patterns were calculated and compared, and the displacement of miniscrews was also evaluated.

RESULTS

The stress/strain distributions are changing with the various bone-implant interfaces. In the scenario of 0% osseointegration, a rather homogeneous distribution was predicted. After 15% osseointegration, the stress/strains were gradually concentrated on the cortical bone region. The miniscrew experienced the largest displacement under the no osseointegra condition. The maximum displacement decreases sharply from 0% to 3% and tends to become stable.

CONCLUSION

From a biomechanical perspective, it can be suggested that orthodontic loading could be applied on miniscrews after about 15% osseointegration without any loss of stability.

[Clinical effects of micro-implant and traditional anchorage in orthodontic treatments]

PURPOSE

To analyze the value of micro-implant and traditional anchorage in the treatment of malocclusion.

METHODS

From Jan 2015 to Jan 2016, 20 cases with malocclusion were randomly divided into control group(10) and experimental group (10). A comparison was conducted between the control group, in which traditional anchorage was used and the experimental group, in which micro-implant anchorage was adopted. The data were analyzed with SPSS 17.0 software package.

RESULTS

There was significant difference of U1-NA, L1-NB, U1-APg, U6-PtPNS between the 2 groups(P<0.05). Adverse reaction was not found in the control group, but 8% in the experimental group(P<0.05).

CONCLUSIONS

Micro-implant anchorage can improve overjet relation of the anterior teeth and effect of orthodontic treatment.

Dentoalveolar and arch dimension changes in patients treated with miniplate-anchored maxillary protraction

INTRODUCTION

The aim of this study was to evaluate dentoalveolar and arch dimension changes in 2 miniplate-anchored maxillary protraction protocols in relation to an untreated control group using 3-dimensional digital models.

METHODS

Thirty growing Class III subjects with maxillary deficiency in the late mixed or early permanent dentition phase were randomly divided into 3 groups. In group 1 (n = 10), patients were treated with skeletally anchored facemasks anchored with miniplates placed at the zygomatic buttress. In group 2 (n = 10), patients were treated with Class III elastics extending from infrazygomatic miniplates in the maxilla to symphyseal miniplates in the mandible. Group 3 (n = 10) was an untreated control group. The decision to discontinue orthopedic treatment was made when the patients had 3 to 4 mm of positive anterior overjet. Pretreatment, posttreatment, and observation 3-dimensional digital models were analyzed, superimposed, 3 dimensionally mapped, and sectioned.

RESULTS

In this study, there were no significant changes in maxillary arch depth and maxillary or mandibular intermolar width before and after maxillary protraction or after the observation period in the control group. The mandibular arch depth decreased by a small but statistically significant amount only in groups 1 and 3. Superimposition of the pretreatment and posttreatment or observation maxillary 3-dimensional digital models showed minimal clinically significant dentoalveolar changes.

CONCLUSIONS

Miniplate-anchored maxillary protraction protocols can accomplish maxillary advancement by eliminating movements of teeth and dentoalveolar changes. No spontaneous improvement in transverse deficiency was detected after correction of the anteroposterior deficiency at this age. Consequently, patients with transverse maxillary deficiency should have rapid maxillary expansion before or during the miniplate-anchored protraction period to improve the transverse deficiency.

[Possibilities and limits of orthodontico-surgical treatments in case of macrodontia]

INTRODUCTION

Tooth-arch discrepancy is a disproportion between dental volume and bone base. Extraction therapy can be a solution in case of excessive tooth volume and insufficient basal bone length. Techniques including bone distraction popularized by Ilizarov in the fifties allow the increase of the basal arch length in the maxilla as well as in the mandible.

MATERIALS AND METHODS

We will describe the procedure of this dental arch length augmentation since the reflection about the therapeutic plan until the sufficient arch length is obtained and describe the indications of this orthodontic and surgical treatment in case of dental crowding, buccal and labial inclination and functional problems.

DISCUSSION

Distraction is an interesting technique to be considered for the management of macrodontia that allows to get enough basal bone lenght to reach the therapeutic goal.

Three Dimensional Virtual Planning Through Cone Beam Computed Tomography for Surgical Guidance Production

This paper describes a methodology through digital planning and computed tomography for the purpose of making surgical guides for insertion of skeletal anchorage devices in dentistry. Mini-orthodontic screws for anchorage are inserted virtually in the region of interest located between the teeth of the second premolar and first molar bilaterally. DICOM images were converted to STL format and overlaid by scanning the upper plaster model in order to plan the surgical guide virtually.

Surgery-related factors affecting the stability of orthodontic mini implants screwed in alveolar process interdental spaces: a systematic literature review

The ambiguous results of scientific researches on surgical factors affecting the stability of mini implants (MI) impels the physicians to constantly analyze this problem. The objective of this article was to conduct a systematic literature review about surgery related factors affecting the stability of MI screwed in alveolar process buccal surface between the second premolar and first molar roots based on peer reviewed publications of 2009-2015. The Cochrane and PRISMA references were used while searching for scientific literature. Two data bases and scientific publications were browsed in the Lithuanian University of Health Sciences library. Criteria for article selection were: 1) research in which surgical factors affecting MI stability were analyzed, 2) research in which stability of MI screwed in alveolar process between adjacent teeth roots was analyzed, 3) research in which MI stability was analyzed in clinical practice, 4) articles which were published in 2009-2015. Selected articles were evaluated in accordance with methodical quality. 13 articles met the selection criteria of the research. 2652 MI screwed in 1205 people jawbones' alveolar processes were analyzed in selected articles. The MI success rate was 87.7-97%. Root proximity was identified to be the main determinant of all MI success influencing surgical factors (MI and root contact determined a 9-26.7% failure rate). The results of this article confirm the sufficient MI stability rate in clinical practice and specifies root proximity as the main surgical factor affecting the MI stability.

[Orthodontic correction of malpositioned teeth before restorative treatment: efficiency improvement using Temporary Anchorage Devices (TADs)]

INTRODUCTION

Orthodontic treatment is a fundamental tool when approaching in a multidisciplinary manner a prosthetic rehabilitation, thanks to the possibility to place in an ideal position the involved teeth and to improve or even correct any periodontal defects. Several orthodontic tricks and version have been developed to limit as much as possible orthodontic appliances extension and treatment duration. However, it is not always easy to control teeth movements and manage anchorage when only few teeth are involved. Furthermore, treatment duration can increase due to the need to apply light forces and to correct adverse dental movements that eventually could appear.

MATERIAL AND METHODS

Different clinical cases are presented.

RESULTS

These exemples illustrate how, with the addition of the TADs in clinical practice, the biomechanics of the multidisciplinary treatment can be simplified, the result becomes highly predictable and the treatment time can often be reduced.

Evaluation of fracture torque resistance of orthodontic mini-implants

This study sought to assess the fracture torque resistance of mini-implants used for orthodontic anchorage. Five commercially available brands of mini-implants were used (SIN®, CONEXÃO®, NEODENT®, MORELLI®, andFORESTADENT®). Ten mini-implants of each diameter of each brand were tested, for a total 100 specimens. The mini-implants were subject to a static torsion test as described in ASTMstandard F543. Analysis of variance (ANOVA) with the Tukey multiple comparisons procedure was used to assess results. Overall, mean fracture strength ranged from 15.7 to 70.4 N·cm. Mini-implants with larger diameter exhibited higher peak torque values at fracture and higher yield strength, regardless of brand. In addition, significant differences across brands were observed when implants were stratified by diameter. In conclusion, larger mini-implant diameter is associated with increased fracture torque resistance. Additional information on peak torque values at fracture of different commercial brands of mini-implants may increase the success rate of this orthodontic anchorage modality.

Initial forces experienced by the anterior and posterior teeth during dental-anchored or skeletal-anchored en masse retraction in vitro

OBJECTIVE

To investigate initial forces acting on teeth around the arch during en masse retraction using an in vitro Orthodontic SIMulator (OSIM).

MATERIALS AND METHODS

The OSIM was used to represent the full maxillary arch in a case wherein both first premolars had been extracted. Dental and skeletal anchorage to a posted archwire and skeletal anchorage to a 10-mm power arm were all simulated. A 0.019 × 0.025-inch stainless steel archwire was used in all cases, and 15-mm light nickel-titanium springs were activated to approximately 150 g on both sides of the arch. A sample size of n = 40 springs were tested for each of the three groups. Multivariate analysis of variance (α = 0.05) was used to determine differences between treatment groups.

RESULTS

In the anterior segment, it was found that skeletal anchorage with power arms generated the largest retraction force (P < .001). The largest vertical forces on the unit were generated using skeletal anchorage, followed by skeletal anchorage with power arms, and finally dental anchorage. Power arms were found to generate larger intrusive forces on the lateral incisors and extrusive forces on the canines than on other groups. For the posterior anchorage unit, dental anchorage generated the largest protraction and palatal forces. Negligible forces were measured for both skeletal anchorage groups. Vertical forces on the posterior unit were minimal in all cases (<0.1 N).

CONCLUSIONS

All retraction methods produced sufficient forces to retract the anterior teeth during en masse retraction. Skeletal anchorage reduced forces on the posterior teeth but introduced greater vertical forces on the anterior teeth.

Predictors of postretention stability of mandibular dental arch dimensions in patients treated with a lip bumper during mixed dentition followed by fixed appliances

OBJECTIVE

To identify which dental and/or cephalometric variables were predictors of postretention mandibular dental arch stability in patients who underwent treatment with transpalatal arch and lip bumper during mixed dentition followed by full fixed appliances in the permanent dentition.

MATERIALS AND METHODS

Thirty-one patients were divided into stable and relapse groups based on the postretention presence or absence of relapse. Intercuspid, interpremolar, and intermolar widths; arch length and perimeter; crowding; and lower incisor proclination were evaluated before treatment (T0), after lip bumper treatment (T1), after fixed appliance treatment (T2), and a minimum of 3 years after removal of the full fixed appliance (T3). Logistic regression analyses were performed to evaluate the effect of changes between T0 and T1, as predictive variables, on the occurrence of relapse at T3.

RESULTS

The model explained 53.5 % of the variance in treatment stability and correctly classified 80.6 % of the sample. Of the seven prediction variables, intermolar and interpremolar changes between T0 and T1 (P = .024 and P = .034, respectively) were statistically significant. For every millimeter of increase in intermolar and interpremolar widths there was a 1.52 and 2.70 times increase, respectively, in the odds of having stability. There was also weak evidence for the effect of sex (P = .047).

CONCLUSIONS

The best predictors of an average 4-year postretention mandibular dental arch stability after treatment with a lip bumper followed by full fixed appliances were intermolar and interpremolar width increases during lip bumper therapy. The amount of relapse in this crowding could be considered clinically irrelevant.

Unpredictability of soft tissue changes after camouflage treatment of Class II division 1 malocclusion with maximum anterior retraction using miniscrews

OBJECTIVE

To compare soft and hard tissue responses based on the degree of maxillary incisor retraction using maximum anchorage in patients with Class II division 1 malocclusion.

MATERIALS AND METHODS

This retrospective study sample was divided into moderate retraction (<8.0 mm; n = 28) and maximum retraction (≥8.0 mm; n = 29) groups based on the amount of maxillary incisor retraction after extraction of the maxillary and mandibular first premolars for camouflage treatment. Pre- and posttreatment lateral cephalograms were analyzed.

RESULTS

There were 2.3 mm and 3.0 mm of upper and lower lip retraction, respectively, in the moderate group; and 4.0 mm and 5.3 mm, respectively, in the maximum group. In the moderate group, the upper lip was most influenced by posterior movement of the cervical point of the maxillary incisor (β = 0.94). The lower lip was most influenced by posterior movement of B-point (β = 0.84) and the cervical point of the mandibular incisor (β = 0.83). Prediction was difficult in the maximum group; no variable showed a significant influence on upper lip changes. The lower lip was highly influenced by posterior movement of the cervical point of the maxillary incisor (β = 0.50), but this correlation was weak in the maximum group.

CONCLUSIONS

Posterior movement of the cervical point of the anterior teeth is necessary for increased lip retraction. However, periodic evaluation of the lip profile is needed during maximum retraction of the anterior teeth because of limitations in predicting soft tissue responses.

Pain and discomfort following insertion of miniscrews and premolar extractions: A randomized controlled trial

OBJECTIVE

To investigate and compare the experience of pain and discomfort between insertion of miniscrews and premolar extractions in adolescent patients.

MATERIALS AND METHODS

A total of 80 adolescents were recruited and randomized into groups A and B. Both groups were treated with extraction of the upper first premolars and fixed appliance. Beyond the fixed appliance, patients in group A received anchorage reinforcement with miniscrews. Miniscrews were inserted buccally between the second premolar and first molar when space closure started. Space closure was performed as en masse retraction with immediate loading by 150-g coil springs. Pain, discomfort, impact on daily activities, and functional jaw impairment were assessed with patient-reported questionnaires. Questionnaires were filled in at baseline, the evening after tooth extraction, 1 week after tooth extraction, the evening after screw placement, and 1 week after screw placement.

RESULTS

Patients reported significantly lower levels of pain (P < .001) and discomfort (P = .012) after screw placement compared with premolar extractions. The ability to drink (P = .035) and the ability to take a big bite (P < .001) were also significantly less disturbed in the evening after screw placement. During the first week after screw placement, the impact on leisure time activities was significantly lower (P = .015) compared with premolar extractions.

CONCLUSION

The use of miniscrews in adolescents can be recommended from a pain and discomfort perspective.

Mandibular and glenoid fossa changes after bone-anchored maxillary protraction therapy in patients with UCLP: A 3-D preliminary assessment

OBJECTIVE

To assess mandibular and glenoid fossa (GF) changes after bone-anchored maxillary protraction (BAMP) therapy in patients with unilateral complete cleft lip and palate (UCLP).

MATERIALS AND METHODS

The cleft group (CG) comprised 19 patients with (mean initial age of 11.8 years). The noncleft group (NCG) comprised 24 patients without clefts (mean initial age of 11.7 years). Both groups had Class III malocclusion and were treated with BAMP therapy for 18 and 12 months, respectively. Cone-beam computed tomography (CBCT) exams were performed before and after treatment and superimposed on the anterior cranial fossa (ACF). Mandibular rotations and three-dimensional linear displacements of the mandible and GF were quantified. A t-test corrected for multiple testing (Holm-Bonferroni method) and a paired t-test were used to compare, respectively, the CG and NCG and cleft vs noncleft sides (P < .05).

RESULTS

Immediately after active treatment, the GF was displaced posteriorly and laterally in both groups relative to the ACF. The overall GF changes in the CG were significantly smaller than in the NCG. Condylar displacement was similar in both groups, following a posterior and lateral direction. The gonial angle was displaced similarly posteriorly, laterally, and inferiorly in both groups. The intercondylar line rotated in opposite directions in the CG and NCG groups. In the CG, most changes of the GF and mandible were symmetrical.

CONCLUSIONS

Overall GF and mandibular changes after BAMP therapy were similar in patients with and without clefts. The exception was the posterior remodeling of the GF that was slightly smaller in patients with UCLP.

Comparison of anterior and posterior mini-implant-assisted maxillary incisor intrusion: Root resorption and treatment efficiency

OBJECTIVE

To compare, through cone-beam computed tomography (CBCT), the root resorption and treatment efficiency of two different mini-implant-assisted modalities in intruding the maxillary incisors.

MATERIALS AND METHODS

Thirty-two adults who had deep bite and elongated maxillary incisors were randomly allocated to two groups: anterior mini-implant group (AMG) and posterior mini-implant group (PMG). In the AMG, approximately 40 g of force was applied per side with elastic chains from mini-implants placed between the lateral incisors and canines and in the PMG, with beta-titanium wires from mini-implants placed between the second premolars and first molars. This study was conducted on CBCT scans taken before intrusion and after 4 months of intrusion. Data were analyzed by means of a paired t-test, independent t-test, and Pearson's correlation test.

RESULTS

One patient was excluded from the AMG due to mini-implant loosening. While the incisors showed a significant reduction in length and volume, this amount was greater in the AMG, especially in the central incisors (P < .05). Together with the mean intrusion rates of 0.62 and 0.39 mm/mo in the AMG and PMG respectively, the center of resistance of the incisors showed distal movement with labial tipping; these changes were greater in the PMG (P < .001). Volumetric root resorption was correlated with the amount of intrusion (P < .05).

CONCLUSIONS

Intrusion anchoring from posterior mini-implants is preferred in cases of upright incisors, as the use of such mechanics directs the roots into the spongiosa where they undergo less root resorption and more labial tipping.