Maxillary Expansion and Mandibular Setback Surgery With and Without Mandibular Anterior Segment Osteotomy to Correct Mandibular Prognathism With Obstructive Sleep Apnea.

Mandibular prognathism is usually treated with mandibular setback surgery. However, this approach reduces the pharyngeal airway space, and can aggravate obstructive phenomena in patients with obstructive sleep apnea (OSA). While maxillary expansion is known to lead to an increase in the pharyngeal airway volume (PAS), its effect on the PAS in mandibular setback surgery has not yet been reported. The authors report a surgical approach with maxillary expansion in 2 patients with mandibular prognathism that was accompanied by OSA: maxillary midsagittal expansion with minimum maxillary advancement and minor mandibular setback without mandibular anterior segmental osteotomy (ASO) or major mandibular setback with mandibular ASO. Preoperative and postoperative computed tomography and polysomnography indicated that OSA was improved and pharyngeal airway space was increased or sustained, and the prognathic profile could be corrected to an acceptable facial esthetic profile. In summary, maxillary transversal expansion and mandibular setback with or without mandibular ASO can be successfully applied to treat mandibular prognathism with OSA.

Influence of craniofacial and upper spine morphology on mandibular advancement device treatment outcome in patients with obstructive sleep apnoea: a pilot study.

BACKGROUND/OBJECTIVES: The aim of the study was to assess cephalometric predictive markers in terms of craniofacial morphology including posterior cranial fossa and upper spine morphology for mandibular advancement device (MAD) treatment outcome in patients with obstructive sleep apnoea (OSA). MATERIAL/METHODS: Twenty-seven OSA patients were treated with MAD for 4 weeks. Apnoea-hypopnoea index (AHI) was recorded before and after MAD treatment. The criteria of treatment success were 75 per cent reduction of AHI. Accordingly, two groups occurred: the success treatment group of 8 patients and the no success treatment group of 19 patients. Before MAD treatment lateral cephalograms were taken and analyses of the craniofacial morphology including the posterior cranial fossa and upper spine morphology were performed. Differences between the groups were analysed by Fisher's exact test, t-test, and multiple regression analysis. RESULTS: Upper spine morphological deviations occurred non-significantly in 25 per cent in the success treatment group and in 42.1 per cent in the no success treatment group. Body mass index (BMI; P < 0.05), maxillary prognathism (S-N-Ss; P < 0.01), mandibular prognathism (S-N-Pg; P < 0.05 and S-N-Sm; P < 0.01), and the distance between sella turcica and the deepest point in posterior cranial fossa (S-D; P < 0.05) was significantly smaller in the success treatment group. The maxillary prognathism (P < 0.05) was the most important factor for the MAD treatment outcome (R (2) = 0.47). LIMITATIONS: Relatively small sample size. CONCLUSIONS: The results indicate that BMI, posterior cranial fossa morphology, and retrognathia of the jaws are factors related to MAD treatment outcome. Furthermore, OSA patients with upper spine morphological deviations may respond poorer to MAD treatment.

Congenital macroglossia treated by 2-stage partial glossectomy.

Persistent macroglossia affects speech, swallowing, and the dentofacial skeleton. A range of tongue reduction methods have been proposed to preserve the mobility and sensation of the tongue. However, recent reports have shown that speech or esthetic problems still exists, even after a comprehensive glossectomy in early childhood. Because a large volume reduction of the anterior tongue in young growing children might result in a short tongue tip with functional difficulties, it is important to select the appropriate tongue reduction method considering the growth of the tongue.In the current report, a staged tongue reduction was planned to minimize the functional and esthetic problems after surgery. A 3-year-old girl visited our clinic because of congenital macroglossia, phonation problems, and prognathic appearance of the mandible. The tongue was first reduced by a central glossectomy. The speech intelligibility, tongue movement, and skeletal growth pattern were improved after the first surgery. The secondary peripheral tongue reduction was performed 6 years later to achieve an esthetically pleasing tongue appearance.This 2-stage partial glossectomy, central tongue reduction first followed later by a peripheral tongue reduction, ensures functional integrity of the tongue and can provide an esthetically pleasing result in growing children. The results demonstrated that this strategic combination of a staged tongue reduction can be a successful treatment option for macroglossia.

Treatment effects of distal movement of lower arch with miniscrews in the retromolar area compared with miniscrews in the posterior area of the maxillary.

OBJECTIVE: The aim of this study was to compare the effects of group distal movement of lower teeth obtained with the aid of direct usage of miniscrews in the retromolar area and indirect usage of miniscrews in the posterior area of the maxillary. METHODS: Nineteen patients with mild-to-moderate class III malocclusion (4 males and 15 females) were divided into 2 groups. Ten patients (2 males and 8 females; mean age, 20.7 ± 2.5 years) in group 1 were treated by miniscrews in the retromolar area. Nine patients (2 males and 7 females; mean age, 21.5 ± 3.7 years) in group 2 were treated by miniscrews in the posterior area of the maxillary. Lateral cephalometric headfilms were taken at the beginning of treatment and after distal movement of mandibular dentition for the evaluation of the treatment changes. RESULTS: In group 1, the crown and root apex of lower first molars were moved distally by 3.4 mm and 1.2 mm with distal tipping of 8.7 degrees and intruded by 0.7 mm. In group 2, the crown and root apex of lower first molars were moved distally by 3.3 mm (P = 0.8976, P > 0.05) and 0.2 mm (P = 0.0124, P < 0.05) with distal tipping of 10.7 degrees (P = 0.0467, P < 0.05) and extruded by 0.2 mm (P = 0.0124, P < 0.05). Retraction of the mandibular arch lasted 6.31 ± 1.45 months for group 1 and 7.61 ± 1.46 months for group 2. CONCLUSIONS: Direct usage of miniscrews in the retromolar area took less time and more bodily movement to retract the lower arch without cooperation of the patients and was a better choice for the patients with potential temporomandibular joint disorders problems.

Temporomandibular disorders after orthognathic surgery in patients with mandibular prognathism with depression as a risk factor.

OBJECTIVE: To examine the prevalence of temporomandibular disorders (TMD) after orthodontic-surgical treatment in patients with mandibular prognathism and analyze psychosocial variables related to TMD. MATERIALS AND METHODS: The case-control study comprised 40 patients with mandibular prognathism who underwent combined orthodontic-surgical treatment (orthognathic surgery group). Forty-two patients with untreated mandibular prognathism served as a control group. Research diagnostic criteria for temporomandibular disorders was used in order to assess the clinical diagnosis of TMD (Axis I) and to estimate depression, somatization and patient's disability related to chronic pain (Axis II). RESULTS: The overall prevalence of TMD was not significantly different between the groups. Myofascial pain was significantly higher, while arthralgia, arthritis and arthrosis was significantly lower in the orthognathic group compared with the controls (90.5% vs 50.0%, 0.0% vs 27.8%, respectively) (p < 0.05). Females in orthognathic surgery group showed higher prevalence of TMD (p < 0.05) and myofascial pain (p < 0.01) and increased level of chronic pain (p < 0.05) in comparison with post-operative males. No significant difference in chronic pain, somatization and depression scores was found between investigated groups. With respect to presence of TMD within the groups depression was higher in untreated subjects with dysfunction (p < 0.05). CONCLUSION: Prevalence of TMD immediately after completion of orthodontic-surgical treatment for mandibular prognathism is similar to frequency of dysfunction in untreated subjects, is significantly higher in females and is most commonly myogenic. Furthermore, females show an increased level of chronic pain post-operatively. Somatization and depression levels do not differ between patients with corrected prognathism and untreated prognathic patients.

Submandibular-space abscess from loss of a bonded molar tube during orthognathic surgery.

The use of bonded orthodontic molar tubes is becoming more prevalent in orthodontics because they have some advantages over conventional bonding. However, a bonded apparatus can become detached, leading to complications. This article presents the case of a submandibular-space abscess associated with a molar tube that detached during orthognathic surgery and became embedded in the soft tissues. The site became infected, and antibiotics were prescribed. Eventually, the molar tube migrated and could be removed under local anesthesia.

Morphologic relationship between the cranial base and the mandible in patients with facial asymmetry and mandibular prognathism.

INTRODUCTION: This study was conducted to measure the dimensional changes in the cranial base and the mandible in patients with facial asymmetry and mandibular prognathism, and to examine the morphologic relationship between asymmetries of the cranial base and the mandible. METHODS: The patients were 60 adults with mandibular prognathism, divided into a symmetry group (menton deviation, <2 mm; n = 30) and an asymmetry group (menton deviation, >4 mm; n = 30) according to the degree of menton deviation. Three-dimensional computed tomography scans were obtained with a spiral scanner. Landmarks were designated on the reconstructed 3-dimensional surface models. Linear, angular, and volumetric measurements of the cranial base and mandibular variables were made. RESULTS: In the asymmetry group, the hemi-base, anterior cranial base, and middle cranial base volumes were significantly larger (P <0.01), and crista galli to sphenoid, sphenoid to petrous ridge, anterior clinoid process to petrous ridge, and vomer to petrous ridge lengths were significantly longer (P <0.05) on the nondeviated side than on the deviated side. Menton deviation was significantly correlated with the difference in hemi-base volume, and ramal volume was significantly correlated with the difference in hemi-base and middle cranial base volumes between the nondeviated and deviated sides (P <0.05). CONCLUSIONS: In patients with facial asymmetry and mandibular prognathism, cranial base volume increased on the nondeviated side and was also correlated with mandibular asymmetry.

Class I malocclusion with severe bimaxillary protrusion: a successful result.

This case report describes the successful treatment of a 29-year-old young woman who had severe bimaxillary dento-alveolar protrusion, with the four premolars already extracted. Her face was convex, with a closed naso-labial angle, protruding and everted lower lip, associated with mentalis strain and a class I canine and molar relationships. After retraction of anterior teeth by using maximum anchorage mechanics through directional forces, facial changes were impressive, with a significant improvement of the dento-alveolar protrusion. Retraction of the incisors had corrected proquelia, reduced lips eversion and had improved the chin projection. As the lips were retracted, mentalis strain was reduced; this improved chin projection.

Posterior crossbite and temporomandibular disorders (TMDs): need for orthodontic treatment?

The aim of this work was to update the bibliography regarding the concept of 'temporomandibular disorder (TMD)' and 'posterior crossbite' and try to find out if there is any association between some special signs/symptoms of TMD and type of posterior crossbite. A literature search from 1970 to 2009, due to specified criterion, resulted in 14 publications that were found to be relevant for the present systematic review. An association between TMD and posterior crossbite (Yes-group) was reported as often as absence of such a relationship (No-group). The samples in the two groups showed similarities as well as differences with respect to number, gender, and age. Most articles reported only on 'presence' or 'absence' of crossbite and only few on type of crossbite opposite to a thorough account of clinical signs and symptoms of TMD. This review seems, however, to state that a functional posterior crossbite (mandibular guidance with midline deviation) is associated with headache, temporomandibular joint and muscular pain, and clicking. As evident from the discussion, such type needs orthodontic treatment to rehabilitate the asymmetric muscular activity between the crossbite and non-crossbite sides and the changed condyle/temporal relationship caused by mandibular deviation. Whether this treatment also will avoid future TMD problems can be answered only after clinical follow-up studies have been performed.

Predisposing conditions for condylar sag after intraoral vertical ramus osteotomy.

Intraoral vertical ramus osteotomy (IVRO) is used to treat mandibular prognathism and temporomandibular disorders. However, the improvement of temporomandibular disorders after IVRO is considered to be due to the anterior and downward movement of the mandibular condyle, which may lead to condylar sag, and in the worst case, condylar luxation. In this retrospective cohort study, we examined factors potentially associated with condylar sag. Univariate analysis indicated that condylar sag was significantly associated with the following factors: magnitude of setback (P = 0.001), less than 3 mm setback (P < 0.001), presence of temporomandibular joint (TMJ) symptoms (P = 0.002), Wilkes classification (P = 0.039), occlusal cant correction ≥ 2 mm (P = 0.018), and mandibular condyle deformation (P < 0.001). Setback magnitude (P = 0.032) and TMJ symptoms (P = 0.007) remained significant in the multivariate analysis. In the receiver operating characteristic curve, the setback magnitude cut-off value for condylar sag after IVRO was 3.25 mm. Thus, the incidence of condylar sag after IVRO is increased with a smaller setback magnitude (≤ 3.25 mm) and the presence of TMJ symptoms. These factors should be evaluated by surgeons during treatment planning for IVRO to estimate condylar sag, and it may be possible to predict the risk of condylar luxation.

Facial morphology changes after total maxillary setback osteotomy.

PURPOSE: To evaluate the morphologic outcome after total maxillary setback osteotomy (TMSO) in dentofacial Class II deformity patients with marked upper jaw prognathism. PATIENTS AND METHODS: The assessments of 9 patients before and after TMSO were compared. The evaluation was based upon x-ray superimpositions and standardized photographic comparison. TMSO was performed through a conventional Le Fort I operation with resection of the inferior end of the pterygoid processes. RESULTS: All patients presented with marked upper jaw prognathism initially and have had a bimaxillary surgery with a mean maxillary setback of 3.1 mm. All patients ended in Class I occlusion after at least 1-year of follow-up. An opening of the nasolabial angle (mean 8.9 degrees) was noted for all but 2 patients. At the same time, the suborbital profile was nicely modified as a result of substantial heightening of the prezygomatic soft tissues in all patients, even without vertical maxillary intrusion. CONCLUSIONS: These results challenge the notion of unavoidable facial alteration commonly associated with upper setbacks. TMSO allows combining satisfactory functional and cosmetic results for a number of carefully selected patients. Pronounced maxillary protrusion with acute nasolabial angle is a prerequisite. The release of the deforming strains of the dysmorphosis upon the midface will improve the suborbital profile. Bimaxillary surgery is recommended to leverage the setback and the opening of the naso-labial angle.

Stress change on the temporomandibular joint in mandibular prognathism subjects with asymmetry after orthognathic surgery.

The purpose of this study was to evaluate changes in stress on the temporomandibular joint (TMJ) in 80 Japanese subjects (21 males and 59 females, mean age 23.7 years) with mandibular prognathism, with and without asymmetry after orthognathic surgery using the rigid bodies spring model (RBSM). The asymmetric group consisted of 40 subjects whose Mx-Md midline was more than 3 degrees. The remaining 40 subjects formed the symmetric group. The geometry of the stress analysis model was based on frontal cephalograms of the subjects. Menton (Me), the centre point of occlusal force on a line connecting the bilateral buccal cusps of the second molars, and the most lateral, superior, and medial points on the condyle were plotted on a computer display and stress on the condyle was calculated with the two-dimensional RBSM program, Fortran. The degree (force partition) of the resultant force, the direction (angulation), and the displacement (X, Y) of each condyle were calculated and the horizontal displacement (u), the vertical displacement (v), and rotation displacement (theta) of the mandibular body at Me were calculated pre- and post-operatively. The data was analysed using paired and unpaired t-tests. For the vertical (v) and rotational (theta) displacement, the post-operative value was smaller than the pre-operative value (v: P < 0.001, theta: P = 0.0063) in the asymmetric group. For angulation and the X-component, the post-operative value was smaller than that pre-operatively on the deviated (angulation: P = 0.0074, X-component: P = 0.0003) and non-deviated (angulation: P = 0.0024, X-component: P = 0.001) side in the asymmetric group. However, there was no significant difference between the pre- and post-operative value for any parameter in the symmetric group. These findings suggest that surgical correction of mandibular prognathism, with and without asymmetry, could induce an improvement in stress balance on the TMJ in the frontal aspect.

Simplified stress analysis on the temporomandibular joint in Class III patients with and without mandibular asymmetry using a rigid body spring model.

OBJECTIVE: Aim of this study was to investigate the differences in stress on the temporomandibular joint (TMJ) between Class III patients with and without mandibular asymmetry using a rigid body spring model (RBSM). DESIGN: Menton (Me), the centre point of occlusal force on the line that connected the bilateral buccal cusps of the second molars and the most lateral, superior and medial points of the condyle were plotted on frontal cephalograms, and stress on the condyles was calculated with the 2-dimensional RBSM program of fortran. SETTING AND SAMPLE POPULATION: Eighty Japanese patients with diagnosed mandibular prognathism were divided into two groups, a symmetry group and asymmetry group on the basis of the Mx-Md midline position. OUTCOME MEASURE: The degree (force partition) of the resultant force, the direction (angulation) and displacement (X, Y) of each condyle were calculated. The horizontal displacement vector (u), the vertical displacement vector (v) and rotation angle (theta) of the mandibular body at Menton were also calculated. RESULTS: There were significant differences between the deviated and non-deviated sides of both groups regarding resultant force (symmetry group: p = 0.0372, asymmetry group: p = 0.0054), X (symmetry group: p < 0.0001, asymmetry group: p = 0.0001) and Y (symmetry group: p = 0.0354, asymmetry group: p = 0.0043). For angulation, there was a significant difference between the deviated and non-deviated sides in the asymmetry group (p = 0.0095). CONCLUSION: The results of this study suggest that difference in stress angulation on the condyles could be associated with asymmetry in mandibular prognathism.

Examination of masticatory movement and rhythm before and after surgical orthodontics in skeletal Class III patients with unilateral posterior cross-bite.

PURPOSE: We examined the movement of the mandible in skeletal Class III patients with a unilateral posterior cross-bite to clarify whether the correction of the cross-bite caused conversion of the masticatory movement from a reverse to a grinding pattern. MATERIALS AND METHODS: We studied 10 adults with mandibular prognathism who had been treated with surgery. The masticatory movement and rhythm (cycle time) during gum chewing were recorded before and after treatment. RESULTS: The results before treatment demonstrated a high frequency of patterns IV, VI, and VII and a low frequency of patterns I, II, and III on the cross-bite side. After treatment, the masticatory movement on the cross-bite side showed different patterns than from before treatment. The high frequency of pattern VI (reverse pattern) before treatment was significantly reduced, and patterns I and III had significantly increased in frequency after treatment. No significant changes were seen in cycle time, opening phase, occlusal phase, or the closing phase before and after treatment. CONCLUSIONS: These results suggest that correction of a unilateral posterior cross-bite induces conversion of the masticatory pattern from the reverse pattern to the grinding pattern.

Glenoid fossa position in Class III malocclusion associated with mandibular protrusion.

INTRODUCTION: Our aim in this study was to investigate the position of the glenoid fossa in subjects with Class III malocclusion associated with mandibular protrusion to better clarify the role of this craniofacial component in Class III skeletal disharmony. METHODS: A sample of 30 subjects, aged 8 years +/- 6 months, with skeletal and dental Class III malocclusion associated with mandibular protrusion, normal skeletal vertical relationships, and normal mandibular dimensions, was compared with a control group of 33 subjects with skeletal and dental Class I relationships. The comparisons between the Class III group and the control group on the cephalometric measures for the assessment of glenoid fossa position were performed with the Mann-Whitney U test at P <0.05. RESULTS: Subjects with Class III malocclusion had a significantly more mesial position of the glenoid fossa, when compared with the control group as measured with 3 parameters. CONCLUSIONS: An anterior position of the glenoid fossa is a possible diagnostic anatomic feature of Class III malocclusion associated with mandibular protrusion. An effective measurement to evaluate glenoid fossa position in craniofacial relationships is the cephalometric distance from the glenoid fossa to the frontomaxillary-nasal suture.

Computational analysis of airflow dynamics for predicting collapsible sites in the upper airways: a preliminary study.

The present study aimed to detail the relationship between the flow and structure characteristics of the upper airways and airway collapsibility in obstructive sleep apnea. Using a computational approach, we performed simulations of the flow and structure of the upper airways in two patients having different facial morphologies: retruding and protruding jaws, respectively. First, transient flow simulation was performed using a prescribed volume flow rate to observe flow characteristics within upper airways with an unsteady effect. In the retruding jaw, the maximum magnitude of velocity and pressure drop with velocity shear and vortical motion was observed at the oropharyngeal level. In contrast, in the protruding jaw, the overall magnitude of velocity and pressure was relatively small. To identify the cause of the pressure drop in the retruding jaw, pressure gradient components induced by flow were examined. Of note, vortical motion was highly associated with pressure drop. Structure simulation was performed to observe the deformation and collapsibility of soft tissue around the upper airways using the surface pressure obtained from the flow simulation. At peak flow rate, the soft tissue of the retruding jaw was highly expanded, and a collapse was observed at the oropharyngeal and epiglottis levels. NEW & NOTEWORTHY Aerodynamic characteristics have been reported to correlate with airway occlusion. However, a detailed mechanism of the phenomenon within the upper airways and its impact on airway collapsibility remain poorly understood. This study provides in silico results for aerodynamic characteristics, such as vortical structure, pressure drop, and exact location of the obstruction using a computational approach. Large deformation of soft tissue was observed in the retruding jaw, suggesting that it is responsible for obstructive sleep apnea.

The Binder syndrome: review of the literature and case report.

Binder syndrome or maxillo-nasal dysplasia (nasomaxillary hypoplasia) is an uncommon developmental anomaly affecting primarily the anterior part of the maxilla and nasal complex. A 4-year-old boy with maxillo-nasal dysplasia (Binder's syndrome), featuring maxillary hypoplasia and relative mandibular prognathism, combined with acute leucosis was presented. We review the literature and describe how three-dimensional CT scanning was used to evaluate the facial morphology. The principal features, diagnosis and management of the syndrome are discussed.