Facemask therapy with rigid anchorage in a patient with maxillary hypoplasia and severe oligodontia

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.

Skeletal Class III malocclusion treatment using mandibular and maxillary skeletal anchorage and intermaxillary elastics: a case report

Introduction:

Skeletal Class III malocclusion is one of the most challenging malocclusions to treat. In around 40% of Class III patients, maxillary retrognathia is the main cause of the problem and in most patients, orthopedic/surgical treatments includes some type of maxillary protraction.

Objective:

The aim of this case report was to describe a treatment method for a patient with maxillary retrognathia and Class III skeletal discrepancy using mandibular and maxillary skeletal anchorage with intermaxillary elastics.

Case report:

A 13-year-old boy with maxillary retrognathia and mandibular prognathism was treated using bilateral miniplates. Two miniplates were inserted in the mandibular canine area and two other miniplates were placed in the infrazygomatic crests of the maxilla. Class III intermaxillary elastics were used between the miniplates.

Results:

After eight months of orthopedic therapy, ANB angle increased by 4.1 degrees and ideal overjet and overbite were achieved. Mandibular plane angle was increased by 2.1 degrees and the palatal plane was rotated counterclockwise by 4.8 degrees.

Conclusion:

This case showed that the skeletal anchorage treatment method may be a viable option for treating patients with Class III skeletal malocclusion.

Temporary Skeletal Anchorage Techniques

As orthodontic treatment has advanced in complexity and in frequency, more recent techniques, using temporary skeletal anchorage, were developed to help correct more severe occlusal and dentofacial discrepancies that were treated with orthognathic surgery alone previously. These techniques have allowed the orthodontist to move teeth against a rigid fixation, allowing for more focused movements of teeth and for orthopedic growth modification. These types of treatments using rigid fixation have allowed for greater interaction between the orthodontist and the oral and maxillofacial surgeon, and have vastly enhanced the treatment planning for the orthodontist in today's society.

Maxillary protraction with rapid maxillary expansion and facemask versus skeletal anchorage with mini-implants in class III patients: a non-randomized clinical trial

Background

The use of skeletal anchorage devices for maxillary protraction in patients with class III malocclusion due to deficiency in the middle third of the face has been shown to be a promising approach to treatment of these patients. The aim of this study was to evaluate the treatment of class III patients with maxillary retrusion, using orthodontic mini-implants (MI) associated with intermaxillary elastics in comparison with the rapid maxillary expansion and facemask protocol (RME/FM).

Methods

In this prospective non-randomized clinical trial, the sample of 24 participants between 7 and 12 years of age (median age of 10.0 years and interquartile range = 3.0 years), at the stage prior to the pre-pubertal growth spurt, was divided in two groups. In group facemask (FM) (n = 12), the individuals received orthopedic treatment with RME/FM. In group MI (n = 12), two mini-implants were inserted in the region close to the maxillary first molar roots, and the other two in the region of the mandibular canines. Initial and final lateral teleradiographs were taken for cephalometric evaluation of all the cases. Statistical analysis included the Mann-Whitney, Wilcoxon, and Fisher’s exact tests. The level of significance was 5% (α = 0.05).

Results

Improvement was verified in the facial profile and occlusion of the participants, showing advancement of the maxilla in the two groups, with significant differences (P ≤ 0.05) between T0 and T1 in the following measurements: SNA, ANB, Wits, Co-A, Co-Gn, NAP, A-Npog, overjet, and molar relationship. There was no statistically significant intergroup difference (P > 0.05) in the cephalometric measurements evaluated, but the time of treatment was significant, and was faster for group MI.

Conclusions

The protocol with mini-implants may be an option for the correction of Class III due to maxillary deficiency.

Induced ankylosis of primary canines for absolute anchorage in the treatment of a patient with Class III malocclusion and cleft soft palate

This case report describes the induced ankylosis of the primary canines for use as absolute anchorage for maxillary protraction. The patient was a young boy with Class III malocclusion and cleft soft palate. The final occlusion was esthetic, functional, healthy, and stable 4 years after treatment.

The clinical outcome of skeletal anchorage in interceptive treatment (in growing patients) for class III malocclusion

A systematic review of the literature was performed regarding the clinical outcome (effectiveness) of bone anchorage devices in interceptive treatment for class III malocclusion. A search of Embase, PubMed and Web of Science databases yielded 285 papers. An additional two articles were retrieved through manual searching of the reference lists. After initial abstract selection, 32 potentially eligible articles were screened in detail, resulting in a final number of eight articles included in this review. Insufficient evidence was found regarding the effects of skeletal anchorage in interceptive class III treatment to support definitive conclusions on long-term skeletal effects and stability. In the short term, it seems that bone anchors can provide more skeletal effect with less dentoalveolar compensations and less unwanted vertical changes. This does not always exclude the use of a face mask. The use of miniscrews as skeletal anchorage device does not seem to provide more skeletal effect, although it could minimize the unwanted dental effects in the upper jaw. No information regarding the need for orthognathic surgery, orthodontic treatment time or patient compliance and complications was found in the selected articles.

Midfacial Protraction With Skeletal Anchorage After Pterygomaxillary Separation

The present article reports the treatment of a 7-year-old girl with maxillary hypoplasia associated with multiple tooth agenesis through maxillary protraction with skeletal anchorage and pterygomaxillary separation. Two titanium mini-plates were placed in the lateral region of the nasal cavity and used as anchorage for maxillary protraction with a reverse-pull facemask. Pterygomaxillary separation was also performed to enhance the effects of maxillary protraction. One week after surgery, 300 g of force was applied on each side to protract the maxilla. Active treatment time was 4 months, with 12 additional months of follow-up. Analysis of the cone beam computed tomography images demonstrated that skeletal anchorage enabled the correction of the maxillomandibular discrepancy, with an improvement in facial appearance and occlusion and with no dental effects. Pterygomaxillary separation was not effective, showing no superior orthopedic response on maxillary advancement or restrictions to maxillary growth in the 12-month post-treatment follow-up.

Comparison of the effects on the pharyngeal airway space of maxillary protraction appliances according to the methods of anchorage

Background

The purpose of the study is to compare the effects on the pharyngeal airway space of skeletal anchored face mask with those of tooth-borne facemask.

Methods

We used two types of facemask for maxillary protraction, the tooth-borne facemask (TBFM) and the skeletal anchored facemask (SAFM), and evaluated the effects of each facemask on the pharyngeal airway. Twenty-eight patients (mean age 10.3 years) were treated with the TBFM and 24 patients (mean age 11.2 years) were treated with the SAFM. Lateral cephalometric radiographs were taken before treatment (T1) and after treatment (T2) to assess changes in the dimensions of the upper airway. Statistical analysis was performed with independent t tests, matched t tests, Mann-Whitney U tests, and Kruskal-Wallis tests.

Results

There were marked increases in upper airway dimensions in both groups following treatment, but the SAFM group had a significantly greater increase in airway dimensions than the TBFM group. Also, the SAFM subgroups showed more improved airway measurements than the TBFM subgroups in both the superior and inferior pharyngeal airways.

Conclusions

SAFM is more effective than TBFM in increasing upper airway dimensions.

Zygomatic miniplates for skeletal anchorage in orthopedic correction of Class III malocclusion: A controlled clinical trial

OBJECTIVE

To evaluate the effects of facemask therapy, which was anchored from the zygomatic buttresses of the maxilla by using two miniplates, in skeletal Class III patients with maxillary deficiency.

METHODS

Eighteen skeletal Class III patients (10 girls and 8 boys; mean age, 11.4 ± 1.28 years) with maxillary deficiency were treated using miniplate-anchored facemasks, and their outcomes were compared with those of a Class III control group (9 girls and 9 boys; mean age, 10.6 ± 1.12 years). Two I-shaped miniplates were placed on the right and left zygomatic buttresses of the maxilla, and a facemask was applied with a 400 g force per side. Intragroup comparisons were made using the Wilcoxon test, and intergroup comparisons were made using the Mann-Whitney U-test (p < 0.05).

RESULTS

In the treatment group, the maxilla moved 3.3 mm forward, the mandible showed posterior rotation by 1.5°, and the lower incisors were retroclined after treatment. These results were significantly different from those in the control group (p < 0.05). No significant anterior rotation of the palatal plane was observed after treatment. Moreover, changes in the sagittal positions of the maxillary incisors and molars were similar between the treatment and control groups.

CONCLUSIONS

Skeletally anchored facemask therapy is an effective method for correcting Class III malocclusions, which also minimizes the undesired dental side effects of conventional methods in the maxilla.

Treatment Options for Class III Malocclusion in Growing Patients with Emphasis on Maxillary Protraction

It is very difficult to diagnose and treat Class III malocclusion. This type of malocclusion involves a number of cranial base and maxillary and mandibular skeletal and dental compensation components. In Class III malocclusion originating from mandibular prognathism, orthodontic treatment in growing patients is not a good choice and in most cases orthognathic surgery is recommended after the end of growth. Approximately 30-40% of Class III patients exhibit some degree of maxillary deficiency; therefore, devices can be used for maxillary protraction for orthodontic treatment in early mixed dentition. In cases in which dental components are primarily responsible for Class III malocclusion, early therapeutic intervention is recommended. An electronic search was conducted using the Medline database (Entrez PubMed), the Cochrane Collaboration Oral Health Group Database of Clinical Trials, Science Direct, and Scopus. In this review article, we described the treatment options for Class III malocclusion in growing patient with an emphasis on maxillary protraction. It seems that the most important factor for treatment of Class III malocclusion in growing patient is case selection.

Corticotomy-assisted maxillary protraction with skeletal anchorage and Class III elastics

OBJECTIVE

To analyze the treatment effects of corticotomy-assisted maxillary protraction with skeletal anchorage and Class III elastics in patients with Class III malocclusions.

MATERIALS AND METHODS

The study group consisted of 19 patients with a mean age of 13.12 ± 1.28 years. Initially, patients were monitored for 5 months before treatment to evaluate growth changes. Changes during control, protraction and fixed orthodontic treatment periods were compared with the cephalometric radiographs taken initially, before protraction, after protraction, and after fixed orthodontic treatment. Treatment outcomes also were compared with the growth effects.

RESULTS

Sagittal measurements of maxilla showed significant improvements (3.59 ± 1.32 mm) during the protraction period (3.85 ± 1.12 months) whereas no significant changes were seen during the control period. Upper and lower incisor inclinations were increased, and the upper occlusal plane angle showed significant counterclockwise rotation during protraction. Significant soft-tissue changes also reflected the underlying skeletal changes. Maxillary advancement was stable during fixed orthodontic treatment.

CONCLUSION

Compared with control period of the patients, this protocol produced significant improvements in skeletal and soft-tissue structures.

Comparison of two maxillary protraction protocols: tooth-borne versus bone-anchored protraction facemask treatment

Background

Protraction facemask has been advocated for treatment of class III malocclusion with maxillary deficiency. Studies using tooth-borne rapid palatal expansion (RPE) appliance as anchorage have experienced side effects such as forward movement of the maxillary molars, excessive proclination of the maxillary incisors, and an increase in lower face height. A new Hybrid Hyrax bone-anchored RPE appliance claimed to minimize the side effects of maxillary expansion and protraction. A retrospective study was conducted to compare the skeletal and dentoalveolar changes in patients treated with these two protocols.

Methods

Twenty class III patients (8 males, 12 females, mean age 9.8 ± 1.6 years) who were treated consecutively with the tooth-borne maxillary RPE and protraction device were compared with 20 class III patients (8 males, 12 females, mean age 9.6 ± 1.2 years) who were treated consecutively with the bone-anchored maxillary RPE and protraction appliances. Lateral cephalograms were taken at the start of treatment and at the end of maxillary protraction. A control group of class III patients with no treatment was included to subtract changes due to growth to obtain the true appliance effect. A custom cephalometric analysis based on measurements described by Bjork and Pancherz, McNamara, Tweed, and Steiner analyses was used to determine skeletal and dental changes. Data were analyzed using a one-way analysis of variance.

Results

Significant differences between the two groups were found in 8 out of 29 cephalometric variables (p < .05). Subjects in the tooth-borne facemask group had more proclination of maxillary incisors (OLp-Is, Is-SNL), increase in overjet correction, and correction in molar relationship. Subjects in the bone-anchored facemask group had less downward movement of the “A” point, less opening of the mandibular plane (SNL-ML and FH-ML), and more vertical eruption of the maxillary incisors.

Conclusions

The Hybrid Hyrax bone-anchored RPE appliance minimized the side effect encounter by tooth-borne RPE appliance for maxillary expansion and protraction and may serve as an alternative treatment appliance for correcting class III patients with a hyperdivergent growth pattern.

Displacements prediction from 3D finite element model of maxillary protraction with and without rapid maxillary expansion in a patient with unilateral cleft palate and alveolus

Background

Both maxillary protraction and rapid expansion are recommended for patients with cleft palate and alveolus. The aim of the study is to establish a three-dimensional finite element model of the craniomaxillary complex with unilateral cleft palate and alveolus to simulate maxillary protraction with and without rapid maxillary expansion. The study also investigates the deformation of the craniomaxillary complex after applied orthopaedic forces in different directions.

Methods

A three dimensional finite element model of 1,277,568 hexahedral elements (C3D8) and 1,801,945 nodes was established based upon CT scan of a patient with unilateral cleft palate and alveolus on the right side in this study. A force of 4.9 N per side was directed on the anatomic height of contour on the buccal side of the first molar. The angles between the force vector and occlusal plane were −30°, −20°, −10°, 0°, 10°, 20°, and 30°. A force of 2.45 N on each loading point was directed on the anatomic height of contour on the lingual side of the first premolar and the first molar to simulate the expansion of the palate.

Results

The craniomaxillary complex displaced forward under any of the loading conditions. The sagittal and vertical displacement of the craniomaxillary complex reached their peak at the protraction degree of −10° forward and downward to the occlusal plane. There were larger sagittal displacements when the maxilla was protracted forward with maxillary expansion. The palatal plane rotated counterclockwise under any of the loading conditions. Being protracted without expansion, the dental arch was constricted. When supplemented with maxillary expansion, the width of the dental arch increased. Transverse deformation of the dental arch on affected side was different from that on unaffected side.

Conclusions

Protraction force alone led the craniomaxillary complex moved forward and counterclockwise, accompanied with lateral constrain on the dental arch. Additional rapid maxillary expansion resulted in a more positive reaction including both larger sagittal displacement and the width of the dental arch increase.

Comparison of short-term effects between face mask and skeletal anchorage therapy with intermaxillary elastics in patients with maxillary retrognathia

INTRODUCTION

The aim of this study was to compare the short-term dental and skeletal effects of a face mask (FM) with those of skeletal anchorage (SA) therapy with intermaxillary elastics in prepubertal patients with skeletal Class III malocclusion.

METHODS

Fifty patients with skeletal Class III malocclusion and maxillary deficiency were divided into two groups. In the FM group, an FM was applied by a bite plate with a force of 400g for each side. In the SA group, mini-plates were placed between mandibular lateral incisors and canines, and mini-implants were inserted between maxillary second premolars and first molars. A bite plate was inserted into the upper arch, and Class III elastics were applied with a force of 200g between each mini-plate and mini-implant.

RESULTS

Mean treatment durations were 0.52±0.09 years for FM and 0.76±0.09 years for SA. After the treatment, statistically significant increases in SNA°, ANB°, A-y, 1-NA, SnGoGn°, Co-A, Co-Gn, and A-Nperp, and reductions in SNB° and FH┴N-Pg were observed in both groups, and these changes were similar in both groups. In the FM group, 1-NB decreased significantly, and in the SA group, it increased significantly (P < 0.05).

CONCLUSIONS

The undesired dentoalveolar effects of the FM treatment were eliminated with SA treatment, except with regard to lower incisor inclination. Favourable skeletal outcomes can be achieved by SA therapies, which could be an alternative to the extraoral appliances frequently applied to treat skeletal Class III patients with maxillary deficiency.

New approach of maxillary protraction using modified C-palatal plates in Class III patients

Maxillary protraction is the conventional treatment for growing Class III patients with maxillary deficiency, but it has undesirable dental effects. The purpose of this report is to introduce an alternative modality of maxillary protraction in patients with dentoskeletal Class III malocclusion using a modified C-palatal plate connected with elastics to a face mask. This method improved skeletal measurements, corrected overjet, and slightly improved the profile. The patients may require definitive treatment in adolescence or adulthood. The modified C-palatal plate enables nonsurgical maxillary advancement with maximal skeletal effects and minimal dental side effects.

Maxillary protraction using skeletal anchorage and intermaxillary elastics in Skeletal Class III patients

The aim of this case report is to describe the treatment of a patient with skeletal Class III malocclusion with maxillary retrognathia using skeletal anchorage devices and intermaxillary elastics. Miniplates were inserted between the mandibular lateral incisor and canine teeth on both sides in a male patient aged 14 years 5 months. Self-drilling mini-implants (1.6 mm diameter, 10 mm length) were installed between the maxillary second premolar and molar teeth, and Class III elastics were used between the miniplates and miniscrews. On treatment completion, an increase in the projection of the maxilla relative to the cranial base (2.7 mm) and significant improvement of the facial profile were observed. Slight maxillary counterclockwise (1°) and mandibular clockwise (3.3°) rotations were also observed. Maxillary protraction with skeletal anchorage and intermaxillary elastics was effective in correcting a case of Skeletal Class III malocclusion without dentoalveolar side effects.

Mini-implants: new possibilities in interdisciplinary treatment approaches

The introduction of mini-implants has broadened the range of tooth movements possible by fixed appliance therapy alone. The limits of fixed orthodontic treatment have become more a matter of facial appearance than anchorage. Many complex cases which would previously have required surgery or functional appliances can now be treated with fixed appliance therapy using mini-implants. A mutilated dentition case where mini-implants were used to provide anchorage for intrusion of molars and retraction of anterior teeth is reported here to illustrate this point.

Displacement and stress distribution of the maxillofacial complex during maxillary protraction with buccal versus palatal plates: finite element analysis

OBJECTIVES

The aim of this study was to analyse the displacement and stress distribution in the maxillofacial complex during maxillary protraction with buccal and palatal plates using three-dimensional finite element analysis.

MATERIALS AND METHODS

Three anchorage appliance models-palatal plate (Type A), miniplate at the infrazygomatic crest (Type B), and conventional tooth-borne appliance (Type C)-were designed and integrated into a skull model. Protraction force was 500 g per side and force direction was forward and 30 degree downward to the maxillary occlusal plane. The stress distribution around the circum-maxillary sutures and the displacement of the surface landmarks were analysed.

RESULTS

All models showed forward and upward displacement at anterior nasal spine, Point A, and prosthion and forward and downward displacement at posterior nasal spine resulting in a counter-clockwise rotation. This anterior displacement was greatest in Type A. At the maxillary process of the zygoma, upward movement was shown only in Type A, whereas downward movement was observed in Types B and C. The greatest stresses in Type A were at the pterygomaxillary and the zygomaticotemporal sutures. Type B showed the greatest stress at the frontomaxillary suture.

LIMITATIONS

Type A showed asymmetric results; however, it was not of clinical significance.

CONCLUSION

The palatal plate resulted in wider stress distribution and more forward displacement compared to miniplate at the infrazygomatic crest area and conventional tooth-borne appliances. It might be recommended to consider the application of the palatal plate for maxillary protraction in Class III patients.

Flexural strength of mini-implants developed for Herbst appliance skeletal anchorage. A study in Minipigs br1 cadavers

OBJECTIVE

The present study was designed to verify if mini-implant prototypes (MIP) developed for Herbst appliance anchorage are capable of withstanding orthopedic forces, and to determine whether the flexural strength of these MIP varies depending on the site of insertion (maxilla and mandible).

METHODS

Thirteen MIP were inserted in three minipig cadavers (six in the maxilla and seven in the mandible). The specimens were prepared and submitted to mechanical testing. The mean and standard deviation were calculated for each region. A two-way Student's t test was used to compare the strength between the sites. A one-way Student's t test was performed to test the hypothesis. Orthopedic forces above 1.0 kgf were considered.

RESULTS

The MIP supported flexural strength higher than 1.0 kgf (13.8 ± 2.3 Kg, in the posterior region of the maxilla and 20.5 ± 5.2 Kg in the anterior region of the mandible) with a significantly lower flexural strength in the anterior region of the mandible (p < 0.05).

CONCLUSIONS

The MIP are capable of withstanding orthopedic forces, and are more resistant in the anterior region of the mandible than in the posterior region of the maxilla in Minipigs br1 cadavers.

The orthopaedic effects of bone-anchored maxillary protraction in a beagle model

SUMMARY BACKGROUND/OBJECTIVES

The purpose of this study was to establish an animal model of bone-anchored maxillary protraction (BAMP) and verify the effects of such treatment in this model.

SUBJECTS/METHODS

Ten total immature (90-day-old) male beagle dogs were used. On Day -20, one miniplate per jaw quadrant was placed and secured with screws. From Day 0 to Day 60, miniplates in the dogs in the intermaxillary traction group (group T, n = 5) were loaded with coil springs. In the control group (group C, n = 5), the miniplates received no force. Every 20 days from Day -20, all dogs were assessed by measuring body weight, taking photographs, and acquiring standardized lateral cephalometric radiographs using a specially designed cephalostat. Cephalometric analyses were performed and the two groups compared. New bone formation was labelled by double-fluorochrome administration with calcein and tetracycline. Animals were sacrificed at Day 60, and bone sections of zygomaticomaxillary sutures were analysed using histomorphometry with fluorescence microscopy. Groups were compared with Mann-Whitney U-tests (P < 0.05).

RESULTS

Cephalometric analysis indicated significant maxillary advancement and retroclination of maxillary incisors in group T, with concomitant significant posterior relocation of the condyles and proclination of the mandibular incisors. In histological analysis, vigorous bone apposition at the zygomaticomaxillary suture was only detected in group T.

LIMITATIONS

Further histological studies would clarify the effects of BAMP on the mandible, especially on temporomandibular articulation.

CONCLUSIONS/IMPLICATIONS

Our results, using this newly developed animal model, support the orthopaedic effects of BAMP.

Effects of placement angle and direction of orthopedic force application on the stability of orthodontic miniscrews

OBJECTIVES

To evaluate the influence of placement angle and direction of orthopedic force application on the stability of miniscrews.

MATERIALS AND METHODS

Finite element analysis was performed using miniscrews inserted into supporting bone at angles of 90°, 60°, and 30° (P90°, P60°, and P30°). An orthopedic heavy force of 800 gf was applied to the heads of the miniscrews in four upward (U0°, U30°, U60°, U90°) or lateral (L0°, L30°, L60°, L90°) directions. In addition, pull-out strength of the miniscrews was measured with various force directions and cortical bone thicknesses.

RESULTS

Miniscrews with a placement angle of 30° (P30°) and 60° (P60°) showed a significant increase in maximum von Mises stress following the increase in lateral force vectors (U30°, U60°, U90°) compared to those with a placement angle of 90° (P90°). In accordance, the pull-out strength was higher with the axial upward force when compared to the upward force with lateral vectors. Maximum von Mises stress and displacement of the miniscrew increased as the angle of lateral force increased (L30°, L60°, L90°). However, a more dramatic increase in maximum von Mises stress was noted in P30° than in P60° and P90°.

CONCLUSION

Placement of the miniscrew perpendicular to the cortical bone is advantageous in terms of biomechanical stability. Placement angles of less than 60° can reduce the stability of miniscrews when orthopedic forces are applied in various directions.

Stress and displacement between maxillary protraction with miniplates placed at the infrazygomatic crest and the lateral nasal wall: a 3-dimensional finite element analysis

INTRODUCTION

The purpose of this study was to compare the pattern and amount of stress and displacement between maxillary protraction with miniplates placed at the infrazygomatic crest and the lateral nasal wall.

METHODS

Three-dimensional finite element models for the skull and the curvilinear type of miniplate were constructed. After a protraction force (500 g/side) was applied to the distal end of the miniplate with a forward and 30° downward vector to the maxillary occlusal plane, stress distributions in the circummaxillary sutures and displacements of the surface landmarks were analyzed.

RESULTS

There was a difference in the maximum stress distribution area according to the site of the miniplate: infrazygomatic crest and middle part of the maxilla in the infrazygomatic crest and paranasal area adjacent to the pyriform aperture in the lateral nasal wall. Stress values of the frontonasal, frontomaxillary, zygomaticomaxillary, and pterygomaxillary sutures were greater in the infrazygomatic crest than in the lateral nasal wall. The site of the miniplate produced differences in the major displacement areas: infrazygomatic crest, maxillary dentition, anterior maxilla, and upper part of the maxillary tuberosity in the infrazygomatic crest and the lateral nasal wall, maxillary dentition, anterior maxilla, and lower part of the maxillary tuberosity in the lateral nasal wall. The lateral nasal wall exhibited forward, downward, and outward displacements of ANS, Point A, and prosthion. However, the infrazygomatic crest showed forward and upward displacements of ANS, Point A, and prosthion, and outward displacement of the zygomatic process of the maxilla and the maxillary process of the zygomatic bone.

CONCLUSIONS

The site of miniplate placement should be considered to obtain proper stress and displacement values in different areas with maxillary hypoplasia.

Use of intermaxillary forces in early treatment of maxillary deficient class III patients: results of a case series

INTRODUCTION

The early treatment of Class III malocclusion with a protraction facemask can produce forward movement of the maxilla but is generally associated with posterior rotation of the mandible and dentoalveolar compensations. This article shows the dental and skeletal effects of intermaxillary elastics applied to temporary anchorage devices in the treatment of maxillary deficient Class III patients.

MATERIALS AND METHODS

A total of 6 patients with skeletal Class III malocclusion were treated with intermaxillary elastics only. This traction was applied between modified miniplates placed in the maxilla and a modified lower acrylic resin plate bonded on mandibular tooth surfaces. To evaluate the orthodontic changes, lateral cephalograms were taken at the start of the treatment (T1), at the end of the orthopaedic treatment (T2) and at the follow-up (T3).

RESULTS

All patients showed orthopaedic correction of the skeletal Class III relationship with reduction of facial concavity. No dentoalveolar compensations or changes in mandibular position were observed.

CONCLUSION

The treatment of maxillary deficiency with orthopaedic forces from skeletal anchorage directed to the hooks of a modified lower acrylic resin plate bonded on the mandibular tooth surfaces, seems to be a promising technique.

Effects of Cleft Type, Facemask Anchorage Method, and Alveolar Bone Graft on Maxillary Protraction: A Three-Dimensional Finite Element Analysis

Objective

To investigate biomechanical effects of cleft type (unilateral/bilateral cleft lip and palate), facemask anchorage method (tooth-borne and miniplate anchorage), and alveolar bone graft on maxillary protraction.

Design

Three-dimensional finite element analysis with application of orthopedic force (30° downward and forward to the occlusal plane, 500 g per side).

Model

Computed tomography data from a 13.5-year-old girl with maxillary hypoplasia.

Intervention

Eight three-dimensional finite element models were fabricated according to cleft type, facemask anchorage method, and alveolar bone graft.

Main Outcome Measure(s)

Initial stress distribution and displacement after force application were analyzed.

Results

Unilateral cleft lip and palate showed an asymmetric pattern in stress distribution and displacement before alveolar bone graft and demonstrated a symmetric pattern after alveolar bone graft. However, bilateral cleft lip and palate showed symmetric patterns in stress distribution and displacement before and after alveolar bone graft. In both cleft types, the graft extended the stress distribution area laterally beyond the infraorbital foramen. For both unilateral and bilateral cleft lip and palate, a facemask with a tooth-borne anchorage showed a dentoalveolar effect with prominent stress distribution and displacement on the upper canine point. In contrast, a facemask with miniplate anchorage exhibited an orthopedic effect with more favorable stress distribution and displacement on the middle maxilla point. In addition, the facemask with a miniplate anchorage showed a larger stress distribution area and suturai stress values than did the facemask with a tooth-borne anchorage. The pterygopalatine and zygomatico-maxillary sutures showed the largest suturai stress values with a facemask with a miniplate anchorage and after alveolar bone grafting, respectively.

Conclusion

In this three-dimensional finite element analysis, it would be more advantageous to perform maxillary protraction using a facemask with a miniplate anchorage than a facemask with a tooth-borne anchorage and after alveolar bone graft rather than before alveolar bone graft, regardless of cleft type.

Three-dimensional assessment of maxillary changes associated with bone anchored maxillary protraction

INTRODUCTION

Bone-anchored maxillary protraction has been shown to be an effective treatment modality for the correction of Class III malocclusions. The purpose of this study was to evaluate 3-dimensional changes in the maxilla, the surrounding hard and soft tissues, and the circummaxillary sutures after bone-anchored maxillary protraction treatment.

METHODS

Twenty-five consecutive skeletal Class III patients between the ages of 9 and 13 years (mean, 11.10 ± 1.1 years) were treated with Class III intermaxillary elastics and bilateral miniplates (2 in the infrazygomatic crests of the maxilla and 2 in the anterior mandible). Cone-beam computed tomographs were taken before initial loading and 1 year out. Three-dimensional models were generated from the tomographs, registered on the anterior cranial base, superimposed, and analyzed by using color maps.

RESULTS

The maxilla showed a mean forward displacement of 3.7 mm, and the zygomas and the maxillary incisors came forward 3.7 and 4.3 mm, respectively.

CONCLUSIONS

This treatment approach produced significant orthopedic changes in the maxilla and the zygomas in growing Class III patients.

Effects of facemask treatment anchored with miniplates after alternate rapid maxillary expansions and constrictions; a pilot study

OBJECTIVE

To describe the dentoskeletal and soft tissue effects of facemask treatment anchored with miniplates after alternate rapid maxillary expansions and constrictions (Alt-RAMEC) in maxillary retrusion patients.

MATERIALS AND METHODS

The sample consisted of 15 patients with a mean skeletal age of 11.6 ± 1.59 years undergoing 8 weeks of Alt-RAMEC followed by maxillary protraction. Three hundred fifty to 400 g of force per side was applied to the facemask from the titanium miniplates inserted on the lateral nasal wall of the maxilla. Total treatment time was 9.9 ± 2.63 months. Treatment changes were evaluated cephalometrically and analyzed by means of the dependent t-test and the Wilcoxon signed rank test.

RESULTS

The miniplates withstood the orthopedic forces exerted during the treatment. Cephalometric findings showed that the maxilla moved forward by 2 mm, with an 0.8° counterclockwise rotation and without maxillary incisor movement. The mandible moved slightly in a downward and backward direction (1.2°). The inclinations of the mandibular incisors decreased significantly (2°). Statistically significant increases were observed in the vertical dimension (1°-1.3°). Soft tissue changes were more marked in the upper lip and soft tissue pogonion than in the lower lip.

CONCLUSIONS

This treatment approach can offer an advantage for correcting mild/moderate maxillary retrusion in Class III patients.

Success rate of miniplate anchorage for bone anchored maxillary protraction

OBJECTIVE

To evaluate the success rate of Bollard miniplate anchorage for bone anchored maxillary protraction (BAMP).

MATERIALS AND METHODS

Twenty-five consecutive patients (mean age, 12.0 ± 1.2 years; range, 8.7-14.8 years) with maxillary hypoplasia without congenital or acquired deformation were included in this study. A total of 100 Bollard modified miniplates were placed by the same surgeon. Ninety-nine miniplates were inserted under general anesthesia, and one was placed under local anesthesia because of initially soft bone conditions. Loading of the miniplates with 150 g elastics was initiated at 17.5 ± 6.9 days (range, 11-38 days) after surgery. Mean follow-up was provided at 20.8 ± 11.1 months (range, 6.5-46.2 months).

RESULTS

The overall success rate of miniplate anchorage in terms of stability was 97%. During orthodontic loading, five miniplates showed signs of mobility. After interruption of loading over 2 months, two miniplates became stable again. However, a total of three miniplates needed to be removed and were successfully replaced under local anesthesia after a mean healing period of 3 months.

CONCLUSION

Skeletal anchorage by means of Bollard modified miniplates is effective for BAMP. Success depends on proper presurgical patient counseling, minimal invasive surgery, good postsurgical instructions, and orthodontic follow-up.

Comparative evaluation of maxillary protraction with or without skeletal anchorage

INTRODUCTION

The aim of this prospective clinical study was to evaluate the skeletal, dentoalveolar, and soft-tissue effects of maxillary protraction with miniplates compared with conventional facemask therapy and an untreated Class III control group.

METHODS

Forty-five subjects who were in prepubertal or pubertal skeletal growth periods were included in the study and divided into 3 groups of 15 patients each. All subjects had skeletal and dental Class III malocclusions with maxillary deficiency, vertically normal growth pattern, anterior crossbite, Angle Class III molar relationship, normal or increased overbite, and retrusive nasomaxillary complex. Before maxillary protraction, rapid maxillary expansion with a bonded appliance was performed in both treatment groups. In the first group (MP+FM), consisting of 5 girls and 10 boys (mean age, 10.91 years), facemasks were applied from 2 titanium miniplates surgically placed laterally to the apertura piriformis regions of the maxilla. The second group (FM) of 7 girls and 8 boys (mean age, 10.31 years) received maxillary protraction therapy with conventional facemasks applied from hooks of the rapid maxillary expansion appliance. The third group of 8 girls and 7 boys (mean age, 10.05 years) was the untreated control group. Lateral cephalometric films were obtained at the beginning and end of treatment or observation in all groups and analyzed according to a structural superimposition method. Measurements were evaulated statistically with Wilcoxon and Kruskal-Wallis tests.

RESULTS

Treatment periods were 6.78 and 9.45 months in the MP+FM and FM groups, respectively, and the observation period in the control group was 7.59 months. The differences were significant between the 3 groups (P <0.05) and the MP+FM and FM groups (P <0.001). The maxilla moved forward for 2.3 mm in the MP+FM group and 1.83 mm in the FM group with maxillary protraction. The difference was significant between 2 groups (P <0.001). The protraction rates were 0.45 mm per month in the MP+FM group and 0.24 mm per month in the FM group (P <0.001). The maxilla showed anterior rotation after facemask therapy in the FM group (P <0.01); there was no significant rotation in the MP+FM group. Posterior rotation of the mandible and increased facial height were more evident in the FM group compared with the MP+FM group (P <0.01). Both the maxilla and the mandible moved forward significantly in the control group. Protrusion and mesialization of the maxillary teeth in the FM group were eliminated in the MP+FM group. The maxillomandibular relationships and the soft-tissue profile were improved remarkably in both treatment groups.

CONCLUSIONS

The undesired effects of conventional facemask therapy were reduced or eliminated with miniplate anchorage, and efficient maxillary protraction was achieved in a shorter treatment period.

Morphometric analysis of treatment effects of bone-anchored maxillary protraction in growing Class III patients

The aim of the present morphometric investigation was to evaluate the effects of bone-anchored maxillary protraction (BAMP) in the treatment of growing patients with Class III malocclusion. The shape and size changes in the craniofacial configuration of a sample of 26 children with Class III malocclusions consecutively treated with the BAMP protocol were compared with a matched sample of 15 children with untreated Class III malocclusions. All subjects in the two groups were at a prepubertal stage of skeletal development at time of first observation. Average duration of treatment was 14 months. Significant treatment-induced modifications involved both the maxilla and the mandible. The most evident deformation consisted of marked forward displacement of the maxillary complex with more moderate favourable effects in the mandible. Deformations in the vertical dimension were not detected. The significant deformations were associated with significant differences in size in the group treated with the BAMP protocol.

Dentofacial effects of bone-anchored maxillary protraction: a controlled study of consecutively treated Class III patients

INTRODUCTION

In this cephalometric investigation, we analyzed the treatment effects of bone-anchored maxillary protraction (BAMP) with miniplates in the maxilla and mandible connected by Class III elastics in patients with Class III malocclusion.

METHODS

The treated sample consisted of 21 Class III patients consecutively treated with the BAMP protocol before the pubertal growth spurt (mean age, 11.10 ± 1.8 years) and reevaluated after BAMP therapy, about 1 year later. The treated group was compared with a matched control group of 18 untreated Class III subjects. Significant differences between the treated and control groups were assessed with independent-sample t tests (P <0.05).

RESULTS

Sagittal measurements of the maxilla showed highly significant improvements during active treatment (about 4 mm more than the untreated controls), with significant protraction effects at orbitale and pterygomaxillare. Significant improvements of overjet and molar relationship were recorded, as well as in the mandibular skeletal measures at Point B and pogonion. Vertical skeletal changes and modifications in incisor inclination were negligible, except for a significant proclination of the mandibular incisors in the treated group. Significant soft-tissue changes reflected the underlying skeletal modifications.

CONCLUSIONS

Compared with growth of the untreated Class III subjects, the BAMP protocol induced an average increment on skeletal and soft-tissue advancement of maxillary structures of about 4 mm, and favorable mandibular changes exceeded 2 mm.

New treatment modality for maxillary hypoplasia in cleft patients. Protraction facemask with miniplate anchorage

OBJECTIVE

To present cleft patients treated with protraction facemask and miniplate anchorage (FM/MP) in order to demonstrate the effects of FM/MP on maxillary hypoplasia.

MATERIALS AND METHODS

The cases consisted of cleft palate only (12 year 1 month old girl, treatment duration = 16 months), unilateral cleft lip and alveolus (12 year 1 month old boy, treatment duration = 24 months), and unilateral cleft lip and palate (7 year 2 month old boy, treatment duration = 13 months). Curvilinear type surgical miniplates (Martin, Tuttlinger, Germany) were placed into the zygomatic buttress areas of the maxilla. After 4 weeks, mobility of the miniplates was checked, and the orthopedic force (500 g per side, 30 degrees downward and forward from the occlusal plane) was applied 12 to 14 hours per day.

RESULTS

In all cases, there was significant forward displacement of the point A. Side effects such as labial tipping of the upper incisors, extrusion of the upper molars, clockwise rotations of the mandibular plane, and bite opening, were considered minimal relative to that usually observed with conventional protraction facemask with tooth-borne anchorage.

CONCLUSIONS

FM/MP can be an effective alternative treatment modality for maxillary hypoplasia with minimal unwanted side effects in cleft patients.

Avaliação in vitro da resistência à flexão de um protótipo de mini-implante desenvolvido para ancoragem do aparelho de Herbst

OBJETIVO: o propósito do presente estudo é avaliar o limite de resistência à flexão de um protótipo de mini-implante desenvolvido para ancoragem do aparelho de Herbst. MÉTODOS: após a realização de um cálculo do tamanho da amostra, quatro corpos de prova contendo os protótipos de mini-implantes foram submetidos a uma força de flexão por engastamento simples, utilizando-se uma máquina universal de ensaios mecânicos, sendo calculado o limite de resistência à força de flexão. RESULTADOS: após os ensaios mecânicos, os novos mini-implantes apresentaram o limite de resistência à força de flexão de 98,2kgf, que foi o menor valor encontrado. CONCLUSÃO: os protótipos de mini-implantes desenvolvidos para ancoragem do aparelho de Herbst foram capazes de suportar forças de flexão maiores do que as forças de mordida descritas na literatura.

Three-dimensional analysis of maxillary protraction with intermaxillary elastics to miniplates

INTRODUCTION

Early Class III treatment with reverse-pull headgear generally results in maxillary skeletal protraction but is frequently also accompanied by unfavorable dentoalveolar effects. An alternative treatment with intermaxillary elastics from a temporary anchorage device might permit equivalent favorable skeletal changes without the unwanted dentoalveolar effects.

METHODS

Six consecutive patients (3 boys, 3 girls; ages, 10-13 years 3 months) with Class III occlusion and maxillary deficiency were treated by using intermaxillary elastics to titanium miniplates. Cone-beam computed tomography scans taken before and after treatment were used to create 3-dimensional volumetric models that were superimposed on nongrowing structures in the anterior cranial base to determine anatomic changes during treatment.

RESULTS

The effect of the intermaxillary elastic forces was throughout the nasomaxillary structures. All 6 patients showed improvements in the skeletal relationship, primarily through maxillary advancement with little effect on the dentoalveolar units or change in mandibular position.

CONCLUSIONS

The use of intermaxillary forces applied to temporary anchorage devices appears to be a promising treatment method.

Use of miniscrews and miniplates in orthodontics

Paradigms have started to shift in the orthodontic world since the introduction of mini-implants in the anchorage armamentarium. For example, miniscrews have allowed the management of wider discrepancies than those treatable by conventional biomechanics because force can be applied directly from the bone-borne anchor unit. Therefore, miniscrews not only free orthodontists from anchorage-demanding cases, but they also enable clinicians to have good control over tooth movement in 3 dimensions. This review will illustrate the versatility of skeletal anchorage provided by mini-implants in the correction of malocclusion, focusing on orthodontic or orthopedic movements in the 3 spatial planes. Adjunctive orthodontic treatments in adult periodontal conditions and treatment for impacted teeth with the aid of miniscrews will also be discussed.