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PubMed2003

Muscular adaptation to gradual advancement of the mandible.

Muscular activity of the superficial masseter muscle and anterior portion of the temporal muscle before, during, and after treatment, with gradual advancement of the mandible, was evaluated by assessing the average integrated electromyogram (EMG) with the mandible in retruded position (RP) and incisal edge-to-edge (EE) position on 23 consecutive subjects with skeletal Class II malocclusion. Toward the end of active treatment and follow-up, the RP position and EE position coincided. At any given registration, the EMG activity of the masseter muscle was at least twice (P < .001) that of the anterior portion of the temporal muscle. The EMG activity in RP for the anterior portion of the temporal muscle was not affected significantly, whereas the EMG activity at EE position decreased significantly (P < .05) during the initial treatment, but, thereafter, it increased continuously. The difference in EMG activity between six months of follow-up and pretreatment level reached statistical significance (P < .05). For the masseter muscle, the EMG activity at both RP and EE position was reduced about 20% during the initial treatment but returned to the pretreatment level during active treatment and exceeded pretreatment level by approximately 30% to 50% at two and six months of follow-up, respectively. In conclusion, it seemed that gradual advancement affected the anterior portion of the temporal muscle to a minor extent, whereas the effect on the masseter muscle was significant.

Adaptation, Physiological↗
PubMed1991

The fetal mandible measurement: an objective determination of fetal jaw size.

The sonographic diagnosis of micrognathia has been limited by the lack of an objective measurement of the fetal mandible. A cross-sectional study of 134 normal patients of known gestational age between 14 and 39 weeks' gestation was performed. Models to predict mandible length based on gestational age, biparietal diameter, head circumference or femur length were derived by least squares regression analysis. The 95% prediction limits were also derived. Utilization of these curves generated from a normal population should allow for a more sensitive and reproducible method to diagnose micrognathia in the fetus.

Journal Article↗
PubMed1997

Immunohistochemistry of collagen types II and X, and enzyme-histochemistry of alkaline phosphatase in the developing condylar cartilage of the fetal mouse mandible.

We investigated the immunohistochemical localisation of types II and X collagen as well as the cytochemical localisation of alkaline phosphatase in the developing condylar cartilage of the fetal mouse mandible on d 14-16 of pregnancy. On d 14 of pregnancy, although no immunostaining for types II and X collagen was observed, alkaline phosphatase activity was detected in all cells in the anlage of the future condylar process. On d 15 of pregnancy, immunostaining for both collagen types was simultaneously detected in the primarily formed condylar cartilage. Alkaline phosphatase activity was also detected in chondrocytes at this stage. By d 16 of pregnancy, the hypertrophic cell zone rapidly increased in size. These findings strongly support a periosteal origin for the condylar cartilage of the fetal mouse mandible, and show that progenitor cells for condylar cartilage rapidly or directly differentiate into hypertrophic chondrocytes.

Alkaline Phosphatase↗
PubMed2000

Primary intraosseous carcinoma of the mandible--a case report and review of the literature.

BACKGROUND: Squamous cell carcinoma arising within bone is a rare lesion and is only seen essentially in the jaw bones. METHODS: A case of primary intraosseous carcinoma arising in the mandible is reported in a 60-year-old female patient. Twenty-eight cases of primary intraosseous carcinoma published in the literature, till date, are reviewed. RESULTS: The mean age of the patients at the time of diagnosis was 53 years and the male: female ratio was 2.2:1. The posterior mandible was the predominant site. Fourteen of 28 patients presented with routine dental disorders, while eight patients complained of swelling, four of severe pain and three had sensory disturbances. The incidence of lymphadenopathy was 10 (34.481%) out of the 29 cases reviewed here. Wide surgical excision is accepted as the treatment of choice. CONCLUSION: The most common presenting symptom of these tumours is swelling and persistent pain in the jaw. Hence, in making a diagnosis one is likely to consider benign dental conditions. The importance of considering intraosseous carcinoma as a possibility in all cases of persistent pain and swelling in the jaw is emphasized so that suitable treatment can be instituted early.

Carcinoma, Squamous Cell↗
PubMed2001

Tissue-engineered composites of bone and cartilage for mandible condylar reconstruction.

PURPOSE: This study evaluated the feasibility of creating a tissue-engineered adult human mandible condyle composite of bone and cartilage. MATERIALS AND METHODS: A polymer template composed of polyglycolic acid (PGA) and polylactic acid (PIA), and formed in the shape of the human mandible condyle, was seeded with osteoblasts isolated from a bovine periosteum suspended in calcium alginate. Chondrocytes isolated from the same calf suspended in 30% pluronic were then "painted" onto the articular surface of the scaffold, and it was then implanted into subcutaneous pockets on the dorsum of athymic mice. Animals were divided into 3 groups: group I (n = 6) received a PGA/PLA scaffold saturated with hydrogels not containing cells; group II (n = 6) received scaffolds seeded with both cell types suspended in saline rather than hydrogels; and group III (n = 6) received scaffolds seeded with both cell types suspended in hydrogel composites. Constructs were harvested after 12 weeks and evaluated grossly and microscopically by using histologic stains. RESULTS: In group I, the constructs formed a small mass without evidence of new bone or cartilage. In group II, the constructs were small and irregular. Microscopically they contained scattered islands of bone and cartilage. All specimens in group III retained their original condylar shape and were quite firm. Microscopic evaluation indicated trabecular bone interfacing with hyaline cartilage on the articulating surface. CONCLUSION: These findings show that the composites of bone and cartilage can be engineered to serve as condylar substitutes. The interdigitation of bone and cartilage at their interface is similar to the normal interface of these composite tissues seen in articulating joints.

Adult↗
PubMed2003

[Topography of the inferior alveolar nerve in relation to cystic processes of the mandible in dental MRI].

PURPOSE: Cystic processes are changing the course of the inferior alveolar nerve in the mandible. This study evaluates the possibility of demonstrating the relationship between space-occupying processes and the course of the neurovascular bundle. MATERIALS AND METHODS: Thirteen patients with cystic processes in the mandible (9 keratocystic lesions, 1 eosinophilic granuloma, 1 plasmocytoma, 2 adamantinomas) were examined by MRI (1.5-T magnet, 8-cm surface coil, PD-gradient-echo-sequences in sagittal and coronal orientation, without enhancement) and the results retrospectively evaluated. RESULTS: The entire course of the nerve could be delineated in all patients. In six patients with minor cystic processes, the nerve was identified in both sagittal and coronal orientation. In seven patients with major cystic lesions, only parts of the nerve were detected in either image orientation, but the nerve could be visualized in its entire length by evaluating coronal and sagittal images side by side. CONCLUSION: It is possible to delineate the inferior alveolar nerve in its entirety along pathologic mandibular lesions. For large cystic lesions, this requires the evaluation of both coronal and sagittal sections of multidirectional MRI.

Adolescent↗
PubMed2004

[Benign diseases of the mandible in MRI].

Diseases of the mandible affect the soft tissues aside from the osseous manifestation. This can be shown clearly and in great detail by magnetic resonance imaging (MRI). MRI is the gold standard in the diagnostic evaluation of any internal derangement of the temporomandibular joint. Dental MRI requires high resolution techniques and in some cases also intravenous administration of contrast material. These techniques allow delineation of the neurovascular bundle. In the past few years new indications were formulated, for example, the evaluation of the integrity of the inferior alveolar nerve in trauma and in radicular cysts. New quantitative methods now enable insights into the pathophysiology. The objective of this review is to communicate accepted indications for MRI of the mandible and to present innovative applications.

Contrast Media↗
PubMed2004

Endoscopic approach to subcondylar mandible fractures.

Current interest in minimally invasive surgery has extended to the repair of craniomaxillofacial fractures, including subcondylar fractures of the mandible. Recent experience indicates that rigid fixation by the endoscopic approach is technically feasible, particularly for subcondylar fractures with lateral displacement of the proximal fragment. The technique is more difficult (although not impossible) for medially displaced fractures. High condylar fractures and comminuted fractures may not be amenable to this approach unless there is enough bone present to allow placement of screws in the proximal fragment. Because evidence suggests that the outcome of open reduction of subcondylar fractures may be better than the outcome when closed management is performed, techniques that minimize the morbidity of open reduction should allow better long-term results. It is hoped that the endoscopic approach for the repair of subcondylar fractures of the mandible will provide these benefits. The technique is summarized with step-by-step explanations.

Endoscopy↗
PubMed1996

[Aneurysmal bone cyst of the mandible].

BACKGROUND: Aneurysmal bone cysts are benign lesions of bone consisting of a septated, cystic cavity filled with non-endothelium-lined, blood-filled spaces. Aneurysmal bone cysts mainly occur in children and adolescents. Only a few occur in the jaws. PATIENT: This is the report of a 9-year-old girl with an aneurysmal bone cyst in the condyle of the mandible who was admitted to the hospital with swelling in front of her right ear. Because of the location and to eliminate recurrence, complete surgical excision of the condyle was performed. DISCUSSION: Fifty-seven cases of aneurysmal bone cyst of the mandible have been reported to date. Aneurysmal bone cyst is treated by surgical excision, which ranges from enucleation and curettage to conservative resection. CONCLUSION: Simple curettage for aneurysmal bone cyst is reported to be associated with a high recurrence rate, a result of the difficulty of completely excising such a vascular lesion. We recommend complete surgical excision as the best treatment.

Bone Cysts, Aneurysmal↗
PubMed2000

Bone-screw mandible fixation: an intraoperative alternative to arch bars.

OBJECTIVES: Bone-screw mandible fixation (BSMF) is evaluated as an alternative to intraoperative arch-bar maxillomandibular fixation before plating of mandibular fractures. BSMF is achieved by wire ligation of opposing bone-screws placed in the maxilla and mandible. METHODS: A retrospective evaluation of 23 patients with 40 mandibular fractures who underwent mandibular fracture repairs. BSMF was used instead of arch bars to ensure proper dental occlusion. All fractures were then plated, after which BSMF was removed before termination of anesthesia. RESULTS: Normal occlusion was observed in 21 patients (91.3%), Class II malocclusion was noted in 1 patient (4. 3%), and 1 patient was edentulous. No complications related to the use of BSMF were observed. CONCLUSION: BSMF can serve as a viable alternative to arch-bar maxillomandibular fixation for obtaining temporary intraoperative occlusion. BSMF produces acceptable malocclusion rates and offers the advantages of decreased intraoperative time, lower risk for percutaneous and mucosal wire punctures, and ease of use.

Accidents, Occupational↗
PubMed2000

Ganglioneuroma of the mandible: radiologic and pathologic findings of a rare tumor.

Ganglioneuroma is a rare benign neural tumor, thought to arise from the ganglia of the sympathetic chain or parasympathetic nervous system. It is therefore most commonly seen in the abdomen and thorax. The occurrence of ganglioneuroma in the mandible is exceptional; to date only 5 cases have been reported. We present another case of ganglioneuroma of the mandible, demonstrate the radiologic and pathologic findings, and discuss the possible causes of the tumor at this site.

Adult↗
PubMed2001

Ultrasound features of osteosarcoma of the mandible--a first report.

Ultrasound imaging is becoming widely used in the head and neck region as a first-line investigation to assess soft tissue swellings. Clinicians should be aware of the potential of diagnostic ultrasound to identify important signs of malignant disease involving bone. Involvement of the mandible by osteosarcoma is uncommon. A young adult patient presented with facial swelling and an apparently infected lower third molar extraction socket. Subtle signs were missed on dental radiographs. Diagnostic ultrasound investigation was pivotal in identifying sinister signs: namely, soft tissue mass associated with bone thinning, erosion, expansion, and the "sunray" appearance of the buccal cortex, which were suggestive of osteosarcoma. These findings enabled priority to be given to subsequent investigations using other modalities. We present a first report of the ultrasound features of osteosarcoma of the mandible and consider this to be a useful modality in an initial investigation.

Adult↗
PubMed2000

A 3d-fem Simulation of Highest Stress Lines in Mandible Fractures by Elastic Impact.

In this article, the more usual mandible fracture areas are located by identifying the highest stress lines using a three-dimensional (tetrahedral) finite element method. By taking into account the temporomandibular contact and the inertia effects, the mathematical model is considered to be a dynamic Signorini's problem, that is, a dynamic variational inequality which is discretized in time following Newmark's method. So, in each time step a stationary variational inequality is solved by a penalty-duality algorithm. Finally, some numerical results obtained by simulating the more usual fractures in the human mandible are presented and compared with clinical experimental information.

Journal Article↗
PubMed2001

Therapeutic possibilities of long-term roxithromycin treatment for chronic diffuse sclerosing osteomyelitis of the mandible.

The clinical efficacy of long-term roxithromycin treatment was examined objectively in nine patients with chronic diffuse sclerosing osteomyelitis of the mandible. Roxithromycin was administered orally at a dose of 300 mg/day for between 68 days and 66 months. In seven of the nine cases (77.8%), the symptoms disappeared 1-12 months after the start of therapy. Radiography showed that osteolytic changes (evident from 'moth-eaten' appearance of bone) had improved but that osteosclerosis had persisted or become more predominant by the end of therapy. Therefore, the optimum duration of treatment should be decided according to the amelioration of symptoms along with the disappearance of osteolytic findings in radiographs. Diarrhoea and stomach discomfort occurred in one case, and liver dysfunction in another, but these adverse reactions were relatively mild. The mechanism of action of roxithromycin in this study is not yet fully understood, but our results indicate that long-term roxithromycin treatment may be useful for diffuse sclerosing osteomyelitis of the mandible and should be attempted before surgical treatment is considered.

Adult↗
PubMed1986

The "black beard" sign of monostotic Paget's disease of the mandible.

Paget's disease of bone can occur in up to 4% of the population over forty. Most of these patients are asymptomatic, and will have more than one bone involved. The monostotic presentation of the disease is much less common, but not rare. Monostotic Paget's disease involving the mandible, however, is very unusual. Only six cases have been reported since 1945, and bone imaging did not play a significant role in the diagnoses of these reports. A patient with proven Paget's disease of the mandible presented with a rather dramatic "bearded" image on a bone scan.

Female↗
PubMed2001

Immediate mobilization following fixation of mandible fractures: a prospective, randomized study.

OBJECTIVES: To compare outcomes of open reduction and internal fixation of displaced mandible fractures followed by either immediate mobilization or 2 weeks of mandibular-maxillary fixation. STUDY DESIGN: A prospective, randomized, single-blinded study was performed. METHODS: The study was performed between January 1, 1997, and March 30, 2000. Inclusion criteria were displaced fractures between the mandibular angles, age greater than 16 years, and no involvement of the alveolus, ramus, condyles, or maxilla. All fractures were repaired by means of open reduction and internal fixation using 2.0-mm titanium plates secured either in transoral fashion or percutaneously. Data were collected at 6-week and 3- and 6-month postoperative examinations. Variables were assessed by a surgeon blinded to the history of immobilization and included pain, malunion or nonunion, occlusion, trismus, wound status, infection rates, dental hygiene, and weight loss. Twenty-nine consecutive patients were enrolled, 16 patients to immediate function and 13 patients to 2 weeks of mandibular-maxillary fixation. RESULTS: No statistically significant differences were found between groups for any of the variables. Immediate release and temporary immobilization showed mean weight loss of 10 and 8 pounds and trismus of 4.2 and 4.6 cm, respectively. One wound separation and one infection were seen in the immobilization population, and no wound separation or infection was seen in the immediate-release group. Dental hygiene was similar between the groups. No malunion or nonunion was noted in either group. CONCLUSIONS: In this prospective and randomized study, no significant differences were noted between the groups receiving either immediate release or 2 weeks of mandibular-maxillary fixation. The findings support the treatment of selective mandible fractures with 2.0-mm miniplates and immediate mobilization.

Adult↗
PubMed2001

Treatment of mandible fractures using low-profile titanium miniplates: preliminary study.

This study evaluated the short-term results of patients treated with low-profile titanium miniplates for fractures of the mandible. Thirty-one fractures of the mandible in 23 patients were treated by open reduction and internal fixation using thin, low-profile miniplates and 1.3-mm self-threading screws. Duration of intermaxillary fixation ranged from 0 to 25 days. Patients were evaluated for complications during a follow-up period ranging from 6 to 24 months. Seven patients (30.4 percent) experienced complications. These included infection (n = 1), premature occlusal contact (n = 1), wound dehiscence (n = 1), temporomandibular joint disorder (n = 1), and paresthesia (n = 3). All complications were minor and adequately managed with incision and drainage, medication, and elastic traction. Low-profile titanium miniplates can be adequately used for internal fixation in selective mandibular fractures. Advantages of these types of plates include comfort due to the thinness of miniplates and ease of application.

Adolescent↗
PubMed2002

Osteoradionecrosis of the mandible after oromandibular cancer surgery.

Although postoperative radiotherapy has proved effective in improving local control and survival in patients with head and neck cancers, its complications, especially mandibular osteoradionecrosis, reduce the quality of life. Mandibular surgery before the radiotherapy adds an additional risk factor for osteoradionecrosis. This study reviews patients in Chang Gung Memorial Hospital, Taipei, Taiwan, over a 10-year period, who underwent intraoral cancer resection followed by postoperative radiotherapy and thereafter developed osteoradionecrosis of the mandible. A total of 24 men and three women with a mean age of 49.9 years were identified and included in the study. In 10 cases, tumor resection was performed with a marginal mandibulectomy; in eight cases, tumor resection was performed after mandibular osteotomy; and in three cases, a segmental mandibulectomy was performed, and the defect was reconstructed with a fibula osteoseptocutaneous flap. In six cases, tumor excisions were performed without interfering with the mandibular continuity. Patients received postoperative external beam radiotherapy into the primary site and the neck, with a mean dose (+/-SD) of 5900 +/- 1300 cGy in an average of 35 fractions during an average of 6.5 weeks. The average elapsed time between the end of radiation therapy and clinical diagnosis of osteoradionecrosis of the mandible was 11.2 months (range, 2 to 36 months). The time elapse between the end of the radiation therapy and the diagnosis of osteoradionecrosis was influenced by initial treatment (Kruskal-Wallis test: n = 27, chi-square = 12.884, p < 0.005), and this period was shorter if the mandibular osteotomy or marginal mandibulectomy was performed (the two lowest mean ranks in the test). However, if the initial surgery resulted in a segmental mandibulectomy reconstructed with a fibula osteoseptocutaneous flap, onset of the osteoradionecrosis was relatively late (Kruskal-Wallis test: n = 21, chi-square = 7.731, p = 0.052). After resection of osteoradionecrotic bone and surrounding soft tissue, 22 patients underwent reconstructive procedures with a fibula osteoseptocutaneous flap, and five patients underwent reconstructive procedures with an inferior genicular artery osteoperiosteal cutaneous flap. One fibula osteoseptocutaneous flap showed total failure and another showed a 25 percent skin loss; both were revised with pedicled flaps. The skin paddle of an inferior genicular artery flap was replaced with an anterolateral thigh flap because of anatomic variation of the skin vessel. Once the diagnosis of osteoradionecrosis is established, replacement of the dead bone and surrounding tissue with a vascularized free bone flap is inevitable, and a composite osteocutaneous free flap is a good option.

Carcinoma, Squamous Cell↗