Mandibular Deficiency Research Articles

Surgical correction of the enlarged tongue

INTRODUCTION Macroglossia is tongue enlargement that leads to functional and cosmetic problems. Although this is a relatively uncommon disorder, it may cause significant morbidity. There is no clear definition of macroglossia and it may be defined in relative, functional, or structural terms. Clinical studies are limited by this lack of a clear definition. Normal speech and swallowing require normal tongue anatomy and function. Swallowing begins as the tongue mixes food with saliva to form a food bolus, which is then propelled into the pharynx by the tongue. Articulation also depends on the tongue's ability to alter the impedance of air, and change the resonant characteristics of the upper airway. macroglossia, increased tongue bulk may impair these functions. There are two types of enlarged tongue ,pseudomacroglossia and true macroglossia. [1234567891011121314] The possible causes for the Pseudomacroglossia are: Habitual posturing of the tongue Enlarged tonsils and/or adenoids displacing tongue Low palate and decreased oral cavity volume displacing tongue Transverse, vertical, or anterior/posterior deficiency in the maxillary or mandibular arches displacing the tongue Severe mandibular deficiency (retrognathism) Neoplasms displacing the tongue Hypotonia of the tongue

Surgical Treatment of Obstructive Sleep Apnea Syndrome Due to Mandibular Deficiency

Background and Objectives: Sleep apnea syndrome affects about 4% of men and 2% of women in middle age. Surgical protocol for obstructive sleep apnea syndrome (OSAS) in patients without maxillomandibular deficiency was well established. However, the optimal surgical treatment of OSAS in patients with facial bony abnormalities needs further studies. Materials and Methods: We demonstrate the effect of surgery in the treatment of OSAS resulted from mandibular deficiency. Nine cases with OSAS due to mandibular deficiency were selected. Patients were examinated and evaluated by cephalometric analysis and polysomnographic data. Three cases were treated by temporomandibular joint (TMJ) reconstruction with costochondral graft. Five cases underwent external distraction osteogenesis (DOG). Mandibular advancement with osteotomy was completed in one case. Results: Though respiratory disturbance index (RDI) improved in some patients, all patients reported improved symptoms and quality of sleep. Conclusion: The surgical procedures of TMJ reconstruction and DOG combined with mandibular advancement are useful to the patients of mandibular deficiency with OSAS.

Mandibular distraction osteogenesis in the pediatric patient

To provide a concise review of recent advances in mandibular distraction osteogenesis as it applies to the field of pediatric otolaryngology. The successful use of mandibular distraction osteogenesis is becoming well established in the literature. Large case series with long-term follow-up are lending strong evidence in support of mandibular distraction osteogenesis in the management of airway obstruction and craniofacial deformities resulting from mandibular deficiency. These recent publications offer refinements in patient selection as well as expanding indications for this surgical intervention. At the same time, an emphasis on reduction of complications and better patient compliance has led to a search for improved device technology. Additionally, there has been an increased interest in understanding of the basic science of distraction osteogenesis at a molecular level. Numerous researchers are investigating the cellular mechanisms involved in distraction osteogenesis bone healing and are attempting to manipulate these factors to improve patient outcomes. The field of pediatric distraction osteogenesis continues to advance with active research and study. As clinical experience increases, new models of device design and molecular manipulation have emerged on the scene, promising improved patient outcomes and fewer complications.

The Importance of Vector Selection in Preoperative Planning of Bilateral Mandibular Distraction

The application of distraction osteogenesis is an effective treatment for mandibular deficiencies. A priori, a horizontal vector of distraction was hypothesized to produce horizontal movement of the mandible and a vertical vector of distraction to produce primarily downward vertical elongation of the ramus. This study was designed to test this hypothesis. A retrospective clinical and radiographic review was conducted of all patients who underwent bilateral, uniplanar distraction with an external device at the New York University Medical Center between October of 1990 and February of 2004 (n = 185). A subset of 15 patients was identified who satisfied inclusion criteria and had adequate predistraction and postdistraction lateral cephalograms. Cephalometric tracings were made and multiple landmarks were assessed before and after distraction. A strong correlation was noted between the vector of distraction and rotation of the symphyseal plane, movement of the mandibular symphysis, and change in interocclusal angle. A horizontal vector of distraction resulted in minimal counterclockwise rotation of the symphyseal plane, greater downward vertical translation of the mandibular symphysis, and minimal closure of an anterior open bite. In contrast, a vertical vector resulted in greater counterclockwise rotation of the symphyseal plane, greater horizontal projection of the mandibular symphysis, and greater closure of an anterior open bite. Mathematical formulas were derived to correlate the distraction vector and mandibular movements. Successful distraction is dependent on accurate prediction of outcomes. This study demonstrates that the vector of distraction predictably affects the mandibular response during bilateral distraction osteogenesis but contradicts the a priori hypothesis.

Postoperative Alopecia Following Orthognathic Surgery

Postoperative alopecia is a pressure-induced, circumscribed area of occipital hair loss, usually after lengthy operative procedures. Prolonged hair follicle ischemia, a result of constant pressure from improper head positioning, is thought to be causative. Most commonly a reversible condition, it can be quite distressing for a patient. The maxillofacial surgeon must understand the pathophysiology and natural history of the condition to correctly identify it and employ measures to prevent it. Here we report a case of postoperative (pressure) alopecia in a female patient after orthognathic surgery. Report of a Case A 37-year-old female underwent Le Fort I osteotomy, bilateral sagittal split osteotomies, and sliding genioplasty to correct a dentofacial deformity, consisting of vertical maxillary excess, mandibular deficiency, and retrogenia. The patient’s head was positioned in the usual fashion, by first placing a head drape, and then resting it on a foam doughnut. The patient had very long hair that had to be gathered posteriorly into the head drape. The 5-hour surgery progressed without complications using a hypotensive anesthesia technique. Mean arterial blood pressure during the case was 65. The patient was discharged on postoperative day 2. At the 3-week follow-up, the patient complained of a “bald” spot at the occipital region near the vertex of the scalp (Fig 1). Upon further questioning, the patient reported a slight discomfort in this area the preceding 3 weeks, but no swelling or ulceration. The patient was reassured and had resolution of hair loss 6 months later.

Dental Arch Dimensions in Class II division 1 Malocclusions with Mandibular Deficiency

To test the hypothesis that there is no difference in the dimensions of the upper and lower dental arches in Class II division 1 malocclusion with a mandibular deficiency compared to normal Class I occlusion dental arches. Photocopies of the dental arches of 48 patients exhibiting Class II division 1 malocclusion with mandibular deficiency and of 51 individuals with normal occlusion were compared. Mandibular deficiency was diagnosed clinically. All 99 individuals were in the permanent dentition. The ages of the subjects ranged from 11 years 4 months to 20 years (mean age = 12 years 5 months). When compared to subjects with normal occlusion, the upper dental arches of the Class II division 1 patients presented reduced transverse dimensions and longer sagittal dimensions while the lower arches were less influenced. The hypothesis is rejected. Significant differences are present between the dimensions of the upper and lower dental arches in Class II division 1 malocclusion (with a mandibular deficiency and in the permanent dentition) compared to normal Class I occlusion dental arches.

Posterior Vertical Deficiencies of the Mandible: Presentation of a New Corrective Technique and Retrospective Study of 21 Cases

The hyperdivergent (high-angle forms of Class II) dentoskeletal deformities are difficult entities to treat. The purpose of this study was to describe and evaluate the use of a new surgical procedure to lower the posterior portion of the occlusal plane during a sagittal split osteotomy of the mandibular ramus, to correct a Class II malocclusion resulting from insufficient development of the mandibular ramus. During a sagittal split osteotomy of the mandibular ramus, the pterygomasseteric sling was completely incised in 21 patients, to treat Class II malocclusion with vertical ramus deficiency. The patients were evaluated clinically, radiologically, and cephalometrically. In all cases, the posterior occlusal plane was successfully lowered, with stable occlusal results, both vertically and sagittally. An increase in the vertical dimension of the ramus remains somewhat more difficult to document. Sagittal split osteotomy of the mandibular ramus with complete incision of the pterygomasseteric sling makes it possible to lower the posterior occlusal plane in cases of posterior vertical mandibular deficiency. This technique, which offers a nonexternal approach, represents a useful additional option for the treatment of these dysmorphoses.

Avaliação cefalométrica dos efeitos do aparelho Herbst no tratamento da deficiência mandibular na dentadura permanente

OBJETIVO: o objetivo do presente estudo cefalométrico retrospectivo consistiu em investigar os efeitos induzidos pelo aparelho Herbst, complementados pela mecânica ortodôntica com aparelho Straight wire e elásticos de Classe II, na correção da má oclusão Classe II, divisão 1, Padrão II, com deficiência mandibular, na dentadura permanente. METODOLOGIA: foram traçadas telerradiografias iniciais (idade média de 12 anos e 10 meses) e finais (idade média de 14 anos e 8 meses) de 18 pacientes, 12 meninos e 6 meninas, para quantificar o comportamento de 12 grandezas cefalométricas representativas da posição sagital das bases apicais, convexidade facial, rotação mandibular e posição sagital dos incisivos superiores e inferiores. O tempo médio de tratamento foi de 22,5 meses, sendo 9,8 meses com o aparelho Herbst e 13 meses com a mecânica ortodôntica subseqüente. RESULTADOS E CONCLUSÕES: os resultados registraram: 1) ausência de influência no comportamento da maxila; 2) avanço mandibular; 3) redução na convexidade facial; 4) preservação da inclinação do plano mandibular e 5) presença de compensação dentária, sobretudo nos incisivos inferiores (vestibularização). Reitera-se, portanto, o fato de que, mesmo com aparelho ortopédico fixo, é mais previsível e mais fácil obter compensação dentária do que remodelação esquelética na correção ortopédica da deficiência mandibular.

Combined trans maxillo-mandibular distraction osteogenesis, a novel approach in skeletal correction

Intraoral transversal mandibular distraction osteogenesis procedures are utilized in many cases of transverse mandibular deficiency with dental crowding of the mandibular anterior teeth. Orthodontics devices regularly cause periodontic disorders and an altered or compromised facial aesthetics. Dental and skeletal positional changes after TMD were studied prior to osteotomies on patients with diverse malocclusions. Le Fort I advancement, trans palatal distraction (TPD) and TMD were performed. Distraction appliances were activated 5 days after the osteotomies at a rate of 1mm/day.

Intraoral Vertical Ramus Osteotomy for Correction of Mandibular Deformity— Complications

Complication after extraoral vertical and intraoral oblique osteotomy have been reported but not in a comprehensive manner. Although intuitively the profile of complications after Intraoral Vertical Ramus Osteotomy (IVRO) would be similar to subcondylar osteotomy, the technique of the two procedures are different, and thus unfavorable outcome after surgery also may differ. The purpose of this study was evaluate the morbidity and complications following correction of mandibular deformity by IVRO. A prospective study was undertaken of 261 consecutively treated orthognathic surgical patients with mandibular deformity (without mandibular deficiency). Each patients was treated by bilateral IVRO with 2-3 weeks of mandibular fixation and no interosseous fixation of the proximal segment. Postoperative stability, immediately after surgery, at 6 months, and at 12 months after surgery were made. Complications consist of vascular complications, nerve injury, infection, condylar luxation and bone hearing were assessed by retrospective individual chart review. The average follow-up 52 months, raging 1 to 17 years. The mean blood loss was 67 g and no severe hemorrhage during operation. There was no wound infection and avascular necrosis after surgery. Inferior alveolar nerve neurosensory disturbance remained 2 (0.4%) operative sites but was disappeared within one year follow up. Malocclusion after surgery was manifest by either relapse or anterior open bite. This occurred in 5 (1.9%) patients but was permanent in 1 patient. Condylar dislocation did not occur. Our studies indicated that surgical correction of mandibular deformity by IVRO had a beneficial effect not only on dental occlusion but also upon complication after surgery.

Sliding Osteotomy Genioplasty for Facial Aesthetic Balance: 10 Years of Experience

The chin, one of the most obvious facial structures, plays an important role in the perception of the face as an instrument of communication. To alter the chin contour in a reliable manner, horizontal sliding osteotomy of the mandibular symphysis with advancement of the mobilized segment is the technique of choice for correction of the anterior posterior deficiency. This study describes surgical techniques used in aesthetic and functional surgery of the chin as well as the outcomes. Over a 10-year period, 474 patients underwent orthognathic surgery for correction of their malocclusion. Of these 474 patients, 155 were treated in combination with a sliding genioplasty (SGP) and 37 (29 women and 8 men; average age, 32 years; range, 18-47 years) had an isolated SGP. Of these patients, 33 had chin advancement and 4 had chin reduction. The mean chin advancement was a modest 4.5 mm (range, 2-7 mm), and the mean chin vertical displacement was 3.9 mm (range, 2.5-4.1 mm). All the patients in the mandibular deficiency group had a residual sagittal disproportion of the progonion relative to the subnasale (mean, -7.6 mm) and a newly created vertical disproportion, with mean lower face heights of 67.8 mm compared with mean midface heights of 65.3 mm. The surgical outcome was evaluated by analysis of pre- and postoperative photographs, analysis of pre- and postoperative measurements, and patients' self judgment. All the patients healed uneventfully without any major postoperative problems. Paraesthesia of the mental nerves occurs to some degree in almost all patients measured by the Simmon Weinstein diagnostic device. In the single sliding chin osteotomy group, no major branches of the mental nerves were transacted. Paraesthesia was only transient, usually lasting for only a few weeks. At least 1 year after the operation, normal sensitivity of the lower lip and both sides of the chin was reported by almost all of the patients (93.1%). All who had only a single genioplasty recovered totally from a neurosensory deficit. The level of satisfaction was significantly high for all the patients. The results were judged to be excellent in 73.2% and good in 23.6% of the cases. Only in 3.2% of the cases was it considered to be poor (bimaxillary surgery combined with SGP). The current findings strongly suggest that SGP is a reliable procedure for achieving harmony of the lower face. In addition, it permits a simplification of facial reconstruction and rejuvenation. The combination of chin advancement and submental recontouring can have a positive effect on facial appearance, provided the increased chin projection is appropriate.

Effects of activator and high-pull headgear combination therapy: skeletal, dentoalveolar, and soft tissue profile changes

The aim of this study was to evaluate skeletal, dentoalveolar, and soft tissue profile changes with activator and high-pull headgear combination therapy in patients with Class II malocclusions caused by maxillary prognathism and mandibular retrognathism. The subjects, all in the mixed dentition, were selected from a single centre and were divided into two groups: 28 patients were treated with an incisor double capping activator and a high-pull headgear combination appliance (13 girls, 15 boys mean chronological age 11.7 +/- 1.2 years, skeletal age 12.1 +/- 1.4 years) and an untreated group of 28 subjects (14 girls, 14 boys mean chronological mean age 11.9 +/- 1.1 years, skeletal age 12.3 +/- 1.3 years). The skeletal, dentoalveolar, and soft tissue profile changes that occurred were compared on lateral cephalograms taken before treatment (T0) and after 1.1 +/- 0.3 years when the combination appliance was removed (T1). In the control group, the radiographs were obtained at the start (T0) and after an observation period 1.2 +/- 0.4 years (T1). Statistical analysis was undertaken with Wilcoxon's ranked-sum test for intra-group comparisons and differences between groups with t-test and Bonferroni's test at a level of significance of P < 0.05. Activator and high-pull headgear combination treatment in these growing patients resulted in a correction of the skeletal Class II relationship (ANB -3.4 degrees), a restriction of maxillary growth (SNA -2.0 degrees, OLp-A -2.3 mm), an advancement of the mandibular structures (SNB +2.6 degrees, FH-NPg +2.3 degrees, OLp-B +2.7 mm, OLp-Pg +2.2 mm), an increase in lower face height (ANS-Me +3.9 mm), a correction of the overjet (-5.4 mm), an improvement in overbite (-2.2 mm), uprighting of the maxillary incisors (U1-FH -5.3 degrees, OLp-U1 -2.5 mm), protrusion of the mandibular incisors (IMPA +2.0 degrees, OLp-L1 +2.7 mm), and a correction of the dental Class II malocclusion (OLp-L6 +3.5 mm). The soft tissue profile changes were a correction of facial convexity (G'-Sn-Pg' angle 2.3 degrees, Mlf-Li-x-axis angle 9.1 degrees), and an increase in lower antero-posterior (Mlf-y-axis 5.6 mm, Pg'-y-axis 5.3 mm), and lower vertical (Sls-x-axis 3.8 mm, Pg'-x-axis 3.8 mm, Me'-x-axis 5.1 mm) soft tissue dimensions. The mentolabial fold depth (Mlf-E line) also significantly decreased, -0.8 mm in the treated group. The activator and high-pull headgear combination appliance was effective in treating growing patients with maxillary prognathism, mandibular deficiency, and facial convexity by a combination of skeletal and dentoalveolar changes and improvement in the soft tissue facial profile.

Condyle as the point of rotation for 3-D planning of distraction osteogenesis for hemifacial microsomia

The purpose of this study is to present an exact simulation method for mandibular rotational movement in distraction osteogenesis for hemifacial microsomia. Three-dimensional (3-D) surgery simulation software programmes (V-Works and V-Surgery; Cybermed, Seoul, Korea) were used, based on 3-D CT data in addition to the conventional data, which included facial photography, panoramic radiograph, cephalogram, and dental models. After measuring the mandibular deficiency (horizontal and vertical) from a 3-D model reconstructed using the software, the angulation of the distraction device to the mandibular border (posterior or inferior) was determined. The rotation axis in the V-Works simulation was defined as the line perpendicular to the plane made by condylion and the distraction vector location on the mandible. The mandible moves along the plane around this rotational axis during distraction. After the 3-D simulation with the software programme, mock surgery on a rapid prototyping model was performed. This planning method was applied to models of two hemifacial microsomia patients. With this protocol, it was possible to simulate the rotational movement of the mandible on the axis passing through the condylar head of the unaffected side. The sequential planning procedure presented in this paper is considered to be helpful in performing effective preoperative simulation of distraction osteogenesis for hemifacial microsomia.

Dental stability and radiographic healing patterns after mandibular symphysis widening with distraction osteogenesis

Distraction osteogenesis is the biological process of new bone formation between bone segments that are gradually separated by incremental traction. The purpose of this study was to assess dental stability and radiographic healing patterns following mandibular symphysis widening with distraction osteogenesis (MSDO) in 19 non-syndromic patients (10 males, 9 females: mean age at the time of surgery 20 years 11 months). To evaluate dental stability, 13 landmarks were measured on the study models of all patients and healing patterns were classified for 11 subjects according to healing times on periapical or occlusal radiographs at three time points: pre-distraction (T1), post-distraction (T2), and follow-up (T3; average 1 year 6 months). Paired t-tests were used to evaluate the change between T2-T1, T3-T2, and T3-T1. The results of this study showed that although there was a decrease in expansion during treatment, the total amount of surgical expansion was maintained. Arch length was significantly increased and irregularity was significantly decreased (both P<0.001). There was evidence of mineralization of the distraction gap in 11 patients within 3 weeks of the end of activation. Radiographically, healing patterns for the distraction gap were diverse, but radiopacity increased over time. MSDO is dentally stable and the distracted gap is mineralized with time, indicating that MSDO is an efficient and stable treatment method in subjects with skeletal mandibular transverse deficiency.

Distraction osteogenesis in a severe mandibular deficiency

ObjectiveDistraction osteogenesis is an alternative treatment method for the correction of mandibular hypoplasia. In this case report, distraction with a multidirectional extraoral device was performed to gradually lengthen the corpus and ramus of a patient who had a severe hypoplastic mandible.Materials and methodsThe patient underwent bilateral extraoral ramus and corpus distraction osteogenesis. After seven days of latency period, distraction was performed 0.5 mm twice a day. Subsequent consolidation period was 12 weeks.ResultsThe patient's mandible was elongated successfully. Cephalometric analysis revealed that ANB angle decreased from 13° to 6°, overjet of 15 mm decreased to 4 mm, corpus length increased from 49 mm to 67 mm, and ramus length increased from 41 mm to 43 mm. Posterior airway space (PAS) also increased due to advancement of the mandible. In stereolithographic model evaluation it was determined that the distances from condylion to gonion and from gonion to pogonion increased.ConclusionSatisfactory results from both aesthetic and functional standpoints were obtained by distraction osteogenesis of the ramus and corpus.

Traumatic neuroma following sagittal split osteotomy of the mandible

A 16-year-old male underwent bilateral sagittal split osteotomy of the mandible to correct a mandibular deficiency. Twenty-one years later, a routine panoramic radiograph revealed a radiolucent lesion on the left side of the mandible. The lesion was biopsied. As the patient did not have symptoms and the lesion was connected to the inferior alveolar nerve, the lesion was not totally excised in order to preserve nerve function. The histological features were consistent with traumatic neuroma, and no further surgical procedure was planned.

Orthodontic treatment changes of chin position in Class II Division 1 patients

Because most patients with skeletal Class II malocclusions also have mandibular deficiencies, treatment plans should include improvement in chin projection. On that basis, the purposes of this study were to (1) determine how Class II treatment affects anteroposterior (AP) chin position in growing subjects and (2) ascertain the most important determinants of AP chin position. Pretreatment and posttreatment lateral cephalograms of 67 treated patients (25 extraction headgear and Class II elastics, 23 nonextraction headgear, and 19 Herbst) were collected, traced, and digitized. The average pretreatment age was 12.2 years (range, 9-14 years), and the average treatment duration was 30.2 months (range, 17-65 months). Cephalometric changes were compared with 29 matched untreated Class II controls. Mandibular superimpositions were used to evaluate condylar growth and true mandibular rotation. All 3 treatment methods produced normal dental relationships and restricted or inhibited AP maxillary growth, with no significant improvement of AP chin position. Differences between changes in vertical position of the maxilla, maxillary and mandibular molars, and condylar growth could not reliably predict changes in chin position. Analyses demonstrated that true mandibular rotation was the primary determinant of AP chin position. Stepwise multiple regression showed that, combined with true mandibular rotation, condylar growth and movements of the glenoid fossa accounted for 81% of the variation in AP changes of pogonion. Contemporary treatments do not adequately address mandibular deficiencies. Future treatments must incorporate true mandibular rotation into Class II skeletal correction.

Unexpected breakage of mandibular midline distraction device: case report

Management of the transverse mandibular deficiency and anterior crowding by mandibular midline distraction osteogenesis (MMDO) is an efficient and stable alternative to orthodontic mechanics with minor complications. Although the only major complication reported previously during MMDO is the nonunion of the segments, in the present case report an unexpected breakage of the distractor in MMDO during the consolidation period as a new major complication was presented.

Association between breastfeeding duration and mandibular retrusion: A cross-sectional study of children in the mixed dentition

In this study, we examined the relationships among breastfeeding duration, nonnutritive infantile sucking habits, Class II facial patterns with mandibular retrusion, and Class II dental relationships. A sample of 249 children in the mixed dentition was examined by 2 orthodontists. Data about the duration of breastfeeding and nonnutritive sucking habits were obtained by written questionnaires answered by the parents. The chi-square test did not indicate a statistically significant association between breastfeeding duration and mandibular deficiency or Class II malocclusion. However, statistically significant associations were found between short breastfeeding duration (<6 months) and nonnutritive sucking habits, and between nonnutritive sucking habits and Class II malocclusions. These findings point to the hypothesis that nonnutritive sucking habits may work as a dominant variable in the relationship between breastfeeding duration and the occurrence of Class II malocclusion. However, the prevention of mandibular deficiency should not be listed as one of the advantages of breastfeeding.

Growth modification of the mandible with ultrasound in baboons: A preliminary report

Growth modification for patients with skeletal Class II malocclusions due to mandibular deficiency is controversial. Low-intensity pulsed ultrasound (LIPUS) can modify mandibular growth in growing rabbits. Before applying this treatment to humans, we must study the effect on mandibular growth in higher animal models. The objective of this study was to evaluate the effect of LIPUS on mandibular growth in baboons. Fourteen juvenile male hamadryas baboons were divided into 2 groups of 7 each. One group received bite-jumping appliances (jumper group), and the other group did not (control group). In both groups, the left temporomandibular joint area received LIPUS (stimulated), and the right side served as the control (unstimulated). Four months after the start of treatment, the baboons were injected with 99-mTc methylene diphosphonate and killed. They were decapitated and scanned for bone growth by using a dual head gamma camera. The mandibles were dissected, sectioned into halves, and radiographed for anthropometric measurements. The condyles were harvested and processed for histological examinations. LIPUS increased mandibular length and growth activity in all treated sides (P<.001), especially in the jumper group. LIPUS enhances mandibular growth in growing baboons, especially when combined with anterior mandibular jumping appliances.