The genetic basis of facial skeletal characteristics and its relation with orthodontics.

Successful treatment of any orthodontic problem depends on an appropriate diagnosis of its etiology. It is well known that the genetics, as well as environmental factors, play an important role on the etiology of skeletal anomalies. Recent studies and advances in genetic sciences allowed the orthodontists to better understand the effects of genetics on the etiology of dentofacial characteristics and pathologies which in turn supported the effects of the genes in the development of dentofacial complex. In orthodontic practice, the genetic basis of a skeletal anomaly should also be considered during the diagnosis. Therefore orthodontic treatment plan should be chosen accordingly. However, further genetic studies are required to clearly determine all the specific genes leading to a particular skeletal variability caused by the polygenic nature of craniofacial traits. This article includes the current information on the association between orthodontics and genetics, an outline of the evidence based impact of heredity on dentofacial development as a review of the etiological factors of skeletal anomalies from the genetic point of view.

Management of an Adult with Spaced Dentition, Class III Malocclusion and Open-bite Tendency.

The aim of this case report was to present the orthodontic treatment of an adult with spaced dentition, Class III malocclusion, and open-bite tendency. A 28.4-year-old adult woman was concerned about the unesthetic appearance of her spaced dentition localized at both upper and lower arches while smiling. She had a mild tongue thrust, hypertropic upper frenum, and mild speech difficulty while pronouncing "s". Her profile was straight with prominent lips. Molar relationship was Class III on both sides. Anterior teeth were in an end-to-end relationship. Lower dental midline was deviated to the left side. Cephalometric analysis revealed a skeletal Class III relationship with hyperdivergent facial pattern. The treatment plan included myotherapeutic exercises for the tongue thrust habit and a diagnostic set-up for closure of diastemas. A strict retention protocol was followed combined with gingivoplasty, fiberotomy, and frenectomy procedures. All spaces were closed successfully, adequate overbite and overjet relationships were obtained, and tongue thrust habit and speech difficulty while pronouncing "s" were eliminated. Clinical and cephalometric results indicated the maintenance of the treatment outcome at 6-months post-retention period.

Arch-width and perimeter changes in patients with borderline Class I malocclusion treated with extractions or without extractions with air-rotor stripping.

INTRODUCTION: The aim of this study was to compare dental arch-width and perimeter changes in patients with borderline Class I occlusion, treated with extractions or without extractions with air-rotor stripping (ARS). METHODS: The study was conducted with 26 sets of pretreatment and posttreatment dental models of patients with borderline Class I occlusion. Thirteen patients (mean age, 18.1 +/- 3.7 years) were treated with 4 premolar extractions, and 13 (mean age, 17.8 +/- 2.4 years) were treated without extractions but with the ARS technique. Mean maxillary and mandibular crowding values were 5.7 +/- 1.5 and 5.9 +/- 1.4 mm in the extraction group, and 5.0 +/- 1.3 and 5.9 +/- 1.3 mm in the nonextraction group, respectively. A digital caliper was used to measure maxillary and mandibular intercanine and intermolar arch widths and arch perimeters. The Wilcoxon test was used to evaluate treatment changes in each group. The Mann-Whitney U test was used to compare the pretreatment and posttreatment values and the treatment changes between the 2 groups. RESULTS: At the start of treatment, the maxillary and mandibular intercanine and intermolar widths and the arch perimeters of both groups did not differ statistically. The maxillary intercanine widths were maintained in both groups. The maxillary and mandibular intermolar widths and arch perimeters decreased in the extraction group. In the nonextraction group, intermolar widths decreased, but arch perimeters did not change significantly. After treatment, the maxillary and mandibular intercanine widths were not different between the groups. CONCLUSIONS: In Class I borderline patients with moderate crowding, extraction therapy with minimum anchorage did not result in narrower dental arches, and nonextraction treatment with ARS preserved the intercanine arch widths and arch perimeters.

Effects of extraction and nonextraction therapy with air-rotor stripping on facial esthetics in postadolescent borderline patients.

INTRODUCTION: A prospective randomized study was designed to compare the skeletal, dental, and soft-tissue profile changes in Class I borderline patients treated with extraction and nonextraction by means of the air-rotor stripping (ARS) technique and to compare the treatment times. METHODS: Twenty-six borderline patients with balanced and orthognathic facial profiles were randomly divided into 2 groups. In the first group, 13 subjects with a mean age of 18.1 +/- 3.7 years and mean maxillary and mandibular crowding of 5.7 +/- 1.5 and 5.9 +/- 1.4 mm, respectively, were treated by removal of 4 premolars with minimum anchorage. In the second group, 13 subjects with a mean age of 17.8 +/- 2.4 years and mean maxillary and mandibular crowding of 5.0 +/- 1.3 and 5.9 +/- 1.3 mm, respectively, were treated with ARS. Lateral cephalometric radiographs and dental models taken before and after treatment were evaluated. RESULTS: The initial skeletal, dental, and profile characteristics of both groups were similar. In the first group, the maxillary and mandibular incisors were slightly retracted, whereas lip positions did not change. In the nonextraction group, maintenance of maxillary incisor position, slight protrusion of the mandibular incisors and the upper and lower lips were observed at the end of treatment. The nasolabial angle decreased significantly. Because of postpubertal growth of the nose and the chin, the lips appeared slightly retrusive after extraction therapy, whereas lip protrusion was compensated in the nonextraction group. The main soft-tissue profile differences between the 2 groups were 1 to 1.5 mm more retruded upper and lower lip positions in the extraction patients, but both groups had well-balanced and desirable facial esthetics with all profile measurements within normal limits. Nonextraction therapy with ARS reduced treatment time by 8 months. CONCLUSIONS: Both extraction and ARS combined with nonextraction therapies are effective treatment alternatives for Class I borderline patients with good facial profile and moderate dental crowding.

Shear bond strength of orthodontic brackets bonded using conventional vs one and two step self-etching/adhesive systems.

OBJECTIVE: To assess and compare the effects of one- and two-step self-etching primer and adhesive with conventional acid-etching and bonding system on the shear bond strength of orthodontic brackets. MATERIALS AND METHODS: The one-step self-etching primer and adhesive used was Clearfil tri-S bond, the two-step fluoride-releasing antibacterial self-etching primer and adhesive was Clearfil Protect Bond, and the fluoride-releasing conventional acid-etching and bonding system was Kurasper F Bond. Brackets were bonded to defect-free human premolars (n = 14 per group) according to each manufacturer's recommendations by using light-cured bracket adhesive Kurasper F Paste with a light-emitting diode of a light-curing unit. The specimens were stored in deionized water at 37 degrees C for 48 hours and then tested in shear with a universal testing machine at a crosshead speed of 5 mm/min until the brackets debonded. The mode of failure of the brackets was determined by a modified adhesive remnant index. RESULTS: Mean shear bond strength values were 9.00 MPa for Kurasper F Bond, 9.55 MPa for Clearfil Protect Bond, and 9.48 MPa for Clearfil tri-S Bond. One-way analysis of variance detected no statistically significant difference among groups (P = .98, P > .05). The predominant failure for the three groups was at the bracket-adhesive interface leaving less than 25% of the adhesive on the bracket base. CONCLUSIONS: One-step self-etching adhesive and two-step fluoride-releasing antibacterial self-etching adhesive have sufficient mechanical properties for the bonding of orthodontic brackets.

Interdisciplinary treatment of an adult patient with old extraction sites.

This case report describes the interdisciplinary treatment of a 31-year-old female patient showing a protrusive profile, maxillary constriction, mandibular crowding, a Class III canine relationship complicated with multiple missing teeth, old atrophic extraction sites, and periodontal defects. The lower dental arch irregularity was eliminated by air-rotor stripping (ARS). The upper extraction site was opened for prosthetic rehabilitation, whereas closure of the lower extraction space was preferred. The narrow alveolar crest of the atrophic bone was augmented with the use of autogenous bone, beta-tricalcium phosphate (Cerasorb), and autogenous platelet-rich plasma. A functional and esthetic occlusion in an improved facial profile was established at the end of orthodontic treatment combined with ARS technique, surgery, and prosthodontics.

Lower lip sucking habit treated with a lip bumper appliance.

The patient was an 11-year-old girl with a lower lip sucking habit with increased overjet, maxillary generalized spacing, and mandibular incisor irregularity. Hyperactivity of the mentalis muscle and deepening of the labiomental sulcus because of the abnormal sucking habit was observed. Orthodontic treatment was started with a lip bumper appliance to break the lower lip sucking habit and continued with fixed orthodontic mechanotherapy. The lip bumper appliance therapy resulted in the elimination of the lower lip sucking habit, musculus mentalis hyperactivity, and labiomental strain in addition to a gain in arch length, improvement of the lower incisor inclinations, and overjet reduction.

Evaluation of dental arch width and form changes after orthodontic treatment and retention with a new computerized method.

The purpose of this study was to evaluate longitudinal arch width and form changes and to define arch form types with a new computerized method. Maxillary and mandibular models of 21 Class II Division 1 patients were examined before treatment (T(0)), after treatment (T(1)), and an average of 3 years after retention (T(2)). Arch width measurements were made directly on scanned images of maxillary and mandibular models. Arch form changes at T(0)-T(1) and T(1)-T(2) were evaluated by superimposing the computer-generated Bezier arch curves with a computer program. Types of dental arch forms were defined by superimposing them with the pentamorphic arch system, which included 5 different types of arch forms: normal, ovoid, tapered, narrow ovoid, and narrow tapered. Maxillary arch widths were increased during orthodontic treatment. Mandibular posterior arch widths were also increased. The expansion of the mandibular arch forms was less than in the maxillary arch forms. Arch width changes were generally stable, except for reduction in maxillary and mandibular interlateral, inter-first premolar, and mandibular intercanine widths. Pretreatment maxillary arch forms were mostly tapered; mandibular arch forms were tapered and narrow tapered. In maxillary arch forms, 76% of the treatment changes were maintained. Mandibular arch form was maintained in 67% of the sample, both during treatment and after retention. In mandibular arches, 71% of orthodontically induced arch form changes were maintained.

A comparative analysis of maxillary tooth movement produced by cervical headgear and pend-x appliance.

The purpose of this study was to compare the effects of cervical headgear and pend-x on the maxillary first molar, second molar, first premolar, and upper incisors. Cephalometric radiographs were obtained at the start of treatment (T1) and after molar distalization was completed (T2) for 13 patients in a pend-x group and 13 patients in a cervical headgear group. The changes of the maxillary teeth were measured on maxillary superimpositions. Nonparametric Mann-Whitney U-test was used to compare the mean differences between the two groups. The mean amount of distalization for the headgear group was 3.15 +/- 1.94 mm and that for the pend-x group was 3.81 +/- 2.25 mm. The second molar teeth were also distalized to a mean amount of 2.27 +/- 1.33 mm in the headgear group and 2.04 +/- 2.15 mm in the pend-x group. The mean treatment time for distalization was 11.38 +/- 3.18 months for the headgear group and 7.31 +/- 4.09 months for the pend-x group. During distalization, the maxillary molars tipped distally in both groups, but intergroup differences were not significant. The anterior inclinations of the first premolar and upper incisor increased significantly in the pend-x group (P < .01). Maxillary molars showed no vertical movement in the pend-x group but extruded in the headgear group (P < .01). The anchorage loss of the pend-x appliance as well as the necessary patient compliance and greater treatment time with the cervical headgear should be taken into consideration.