Biomechanical validation of a modified genioplasty distractor.

PURPOSE: Genioplasty is a surgical procedure that is used to enhance the shape and appearance of the chin. It can be performed alone or in combination with other jaw-related surgeries either for medical or cosmetic purposes. Recently many studies have been reported for mandibular reconstruction with distraction osteogenesis. However, these distractors can cause some complications such as incorrect prolongation of hard tissues due to the lack of guiding section. The purpose of this study is to manufacture a novel genioplasty distractor and measure its biomechanical stability and reliability for different activation lengths in mandibular bone. METHODS: The modified genioplasty distractor was manufactured from grade 2 and grade 5 (Ti6AI4V) titanium alpha + beta alloy which was biocompatible and adequately rigid for possible in situ application in the future and a sample holder was manufactured for compressive strength testing. RESULTS: Test results showed that our modified genioplasty distractors withstood 300 N compression force for activation lengths from 0 to 11 mm. Recorded stress values were in the range of 0.110 MPa to 0.389 MPa. CONCLUSION: The modified genioplasty distractor developed and tested here is a promising surgical tool that has the potential to reduce genioplasty related complications especially in demanding cases.

The effects of maxillary expansion on the soft tissue facial profile.

PURPOSE: The aims of this retrospective study were to evaluate the possible changes in soft tissue facial profile induced by orthopedic rapid maxillary expansion (RME) and surgically assisted rapid maxillary expansion (SARME), and to correlate them with the underlying hard tissue alterations. MATERIALS AND METHODS: 16 patients who received bone borne SARME and 25 patients who were subjected to RME using metal cast splint hyrax appliance were analyzed retrospectively. This research was conducted on lateral cephalometric radiographs taken on 2 occasions: before expansion (T1) and at the beginning of any further orthodontic treatment (T2). Investigated lateral cephalometric parameters consisted of Holdaway soft tissue measurements with some supplementary soft tissue, skeletal and dental assessments. RESULTS: The acquisition of T2 cephalograms which conforms to the initiation of further orthodontic treatment corresponded to 83.25±3.51 days for SARME and 85.68±4.37 days for RME after the expansion was completed. The only significant change in soft tissue profile of the SARME group was a decrease in upper lip thickness (p<0.05), whereas in the RME group, decrease in soft tissue facial profile angle and increase in H angle were found to be statistically significant (p<0.05 for each). For the RME group, the changes in soft tissue facial profile angle and H angle correlated only with the changes in SNB angle (p<0.05). CONCLUSION: While bone-borne SARME did not seem to possess the potential to alter soft tissue profile, tooth-borne RME caused a more convex soft tissue profile related to a reduction in SNB.

Treatment of lateral open bite with vertical dentoalveolar distraction osteogenesis.

The aim of this article is to describe the surgical, orthodontic, and periodontal treatment of an adult patient with a lateral open bite, anterior crowding, and gingival recession on the mandibular right lateral incisor. The lateral open bite, which resisted conventional mechanics, was successfully corrected by the combination of dento-osseous osteotomies and vertical alveolar distraction using orthodontic multibracket appliances in conjunction with nickel-titanium archwires and intermaxillary elastics. After the orthodontic treatment, the denuded root surface of the mandibular right lateral incisor was closed using a coronally advanced flap technique with platelet-rich fibrin. The results at the 2-year posttreatment follow-up were satisfactory from both the occlusal and the periodontal standpoints.

Does transpalatal distraction affect pharyngeal airway dimensions and related soft tissues?

PURPOSE: Previous studies of transpalatal distraction (TPD) have been based on dentoskeletal alterations of the jaws and nasal airway changes. The main aim of this study was to determine the effects of TPD on soft palate and pharyngeal airway dimensions and tongue posture. MATERIAL AND METHODS: This was a retrospective cohort study. The sample was comprised of 16 patients with skeletal maxillary deficiency who had bilateral crossbite combined with a high palatal vault and partial or near total nasal obstruction treated with TPD using bone-borne distractors (Transpalatal Distractor, SurgiTec NV, Bruges, Belgium). This research was carried out on lateral cephalometric radiographs taken before distraction and after a distraction period of 6.75 ± 1.61 months. The primary predictor variable was pharyngeal airway dimensions and tongue posture. Other variables were demographic and lateral cephalometric parameters. Changes in the length, angle, and thickness of the soft palate; nasopharyngeal, retropalatal, retroglossal, and lower pharyngeal airway dimensions; and tongue length and height were evaluated. Data were analyzed by paired t test. RESULTS: The sample included 16 adult patients (mean age, 25.13 ± 6.13 yr; 7 women, 9 men). The desired amount of distraction was achieved in all patients within 7 to 10 days. The total activation average was 8.38 ± 0.96. TPD caused statistically significant changes in sagittal nasopharyngeal airway dimensions (1.19 mm), the minimal oropharyngeal distance behind the tongue base (1.81 mm), and tongue height (2.12 mm). CONCLUSIONS: The results of this study suggest that, in adult patients with nasal obstruction, TPD has the potential to increase sagittal nasopharyngeal airway dimensions and the minimal oropharyngeal distance behind the tongue, with an elevation in tongue posture. Further studies using cone-beam computed tomography that focus on how the bone-borne expander alters pharyngeal airway volume will make valuable contributions to the literature.

Treatment of nonsyndromic dentigerous cysts in primary dentition.

OBJECTIVE: Dentigerous cysts are benign odontogenic cysts that are associated with the crowns of permanent teeth. They usually occur singly and are located in the mandible. Nonsyndromic bilateral dentigerous cysts (NSBDC) are rarely seen during childhood. The aim of this study was to determine the long-term effects of the marsupialization technique in growing children with NSBDC. STUDY DESIGN: Seven patients with NSBDC (4 female, 3 male) ranging in age from 7 to 9 years (mean 8.35 years) were involved in the study. All the individuals were treated by marsupialization. Space-maintaining appliances were applied during permanent teeth eruption. Intraoral photographs, and panoramic and periapical films were taken before surgery and during healing. RESULTS: The NSBDC were successfully treated by the marsupialization technique and rapid healing period was observed in the growing patients, without any loss of permanent teeth. No recurrence was seen in the long-term follow-up period (3-10 years). CONCLUSION: Our clinical and radiological results revealed that using the marsupialization technique in children with NSBDC provided safe healing of permanent teeth around the dentigerous cysts in a short period. However, treatment planning and regular clinical follow-ups are necessary to ensure clinical success.

Dimensional changes of the nasal cavity after transpalatal distraction using bone-borne distractor: an acoustic rhinometry and computed tomography evaluation.

PURPOSE: The aims of this study were as follows: 1) evaluation of the effects of transpalatal distraction (TPD) on nasal minimum cross-sectional area (MCA) and nasal volume, and assessment of long-term stability of TPD outcomes on the nasal cavity, using acoustic rhinometry (AR); 2) quantifying the alveolar, basal, and nasal components of the maxillary expansion at both canine and molar levels by computed tomography (CT); 3) investigation of the relationship between CT transverse measurements and AR measurements. PATIENTS AND METHODS: The sample was comprised of 11 adult patients with maxillary transverse deficiency and partial/near total nasal obstruction. Standard corticotomies were carried out and bone-borne transpalatal distractors were used in all cases. AR recordings were used to determine nasal minimum cross-sectional area of the anterior (MCA1) and posterior (MCA2) and the volume of the nasal cavity in these regions (Volume1, Volume2) before surgery (T1), when the distractor was removed (T2), and at least 1 year after the expander was removed (T3). CT images were taken at T1 and T2. CT measurements included maxillary base, alveolar, and nasal cavity widths at both canine and first molar slices. RESULTS: There were significant increases in MCAs and volumes of nasal cavity between T1 and T2 and between T1 and T3 with the exception of the right MCA2 and right Volume2 at the latter time (P < .05). All maxillary transverse dimensions in canine and molar CT slices displayed significant increases (P < .05). The change in binasal width at the canine level showed significant correlations with the changes in total MCA1 and total Volume1 (P < .05). CONCLUSION: TPD provided great increases in MCA and volume of the nasal cavity, and these changes generally remained stable long term. The use of TPD in adult patients granted the opportunity of efficient maxillary expansion concurrent with increases in the nasal dimensions.

Enhanced effect of combined treatment with corticotomy and skeletal anchorage in open bite correction.

PURPOSE: To determine the effects of combined treatment with corticotomy and skeletal anchorage in open bite correction. PATIENTS AND METHODS: Ten patients (6 females, 4 males) with ages ranging from 15 to 25 years were involved. All of the individuals received combined subapical corticotomy and skeletal anchorage procedure and intrusion forces of 200 to 300 g were applied on the attachments of each molar and both premolars during 12 to 15 weeks. Mean changes for the measurements for the sample group were evaluated with Wilcoxon signed ranks test. RESULTS: Significant intrusion of maxillary posterior teeth provided counterclockwise rotation of the mandible and open bite was successfully corrected. SNB angle increased and the ANB angle decreased (P< .05). Significant decreases were noted for vertical skeletal characteristics and overbite increased accordingly (P< .05). CONCLUSIONS: Our results indicated that the use of combined treatment with corticotomy and skeletal anchorage provided safe and noncompliance intrusion of posterior teeth in a short period and may be regarded as an alternative method for skeletal open bite correction in adults who reject orthognathic surgery.