Lingual Cortical Bone Research Articles

Comparison of the Buccal and the Lingual Cortical Bone Mineral Density and Their Relation to the Trabecular Bone in the Mandible

Comparison of the Buccal and the Lingual Cortical Bone Mineral Density and Their Relation to the Trabecular Bone in the Mandible

Central acinic cell carcinoma of the mandible. Case report

Central acinic cell carcinoma (of the mandible) is rare, and, to our knowledge, only seven cases of this disease have been reported in the literature. A case in a 67-year-old Japanese woman is presented. Clinical examination revealed a 10.0×6.0 mm mass located on the buccal aspect of the gingiva of the second molar in the left mandible. Radiographic examination revealed a radiolucency from the second to the third molar of the left mandible. Computed tomography disclosed destruction of the lingual cortical bone of the third molar region. The preliminary diagnosis was of odontogenic tumour. The patient was admitted, and removal of the tumour and of the involved teeth were carried out. Histological examination disclosed the diagnosis of acinic cell carcinoma. Subsequently, the tumour area was widely excised from the second premolar region to the coronoid process, and radical neck dissection was performed. A lymph node metastasis was found in the submandibular region. No recurrence or metastasis was observed during the 34-month follow-up.

Loaded hydroxylapatite-coated implants and uncoated titanium-threaded implants in distracted dog alveolar ridges

The aim of this study was to determine the response of alveolar bone after it was augmented vertically with distraction osteogenesis, implanted with hydroxylapatite (HA)-coated implants and noncoated titanium-threaded implants, and subsequently loaded for 1 year. Eight dogs each had 4 implants placed horizontally into an edentulous mandibular quadrant. After integration, a distraction osteogenesis device was fabricated in the laboratory. An osteotomy was made to allow the crest of the alveolar ridge to be distracted vertically. After 10 mm of vertical distraction, the distraction devices were stabilized with light cured resin. After bone fill of the distraction gap was radiographically confirmed in all dogs at 10 weeks, 2 implants were placed into the ridges. Four dogs had threaded titanium implants placed, and 4 dogs had threaded HA-coated implants placed, with 1 implant in the distracted bone and 1 implant in adjacent nondistracted bone, for both groups. After 4 months for implant integration, bridges were fabricated and secured to the implants with screws. Crestal bone levels were evaluated by radiographs through 1 year of function. Animals were killed after 1 year of loading for histologic evaluation. The vertical ridge augmentation averaged 8.8 +/- 1.0 mm after 10 weeks of healing after distraction. Analysis of variance indicated a significantly greater change from baseline for HA-coated implants and for distracted bone sites. Histologic examination showed that bone had formed between the distracted segments creating an augmented ridge. The average thickness of the labial cortex in the distraction gap was significantly thinner than the lingual cortex in distracted bone or the lingual and labial nondistracted cortical bone. The presence of a dental implant did not significantly affect cortical bone thickness. Serial sections showed that implants remained integrated and functional without soft tissue inflammation. Dental implants placed into alveolar ridges augmented with the technique of distraction osteogenesis were functional for the length of this study.

Clinical and histological findings in guided bone regeneration (GBR) around titanium dental implants with autogeneous bone chips using a new resorbable membrane.

The aim of this study was to test the value of a polydioxanon-membrane (PDS(R), Ethicon, Norderstedt, Germany) in combination with autogenous bone as a spacer for guided bone regeneration of denuded implant surfaces in comparison to simple augmentation. Altogether, in 8 Beagle dogs of 12 months, the three mandibular premolars were extracted on both sides and, after an uneventful healing of the extraction sockets in each mandibular site, two seize defined bone defects were produced. The defects were 7 mm long, had a vertical extension of 7 mm, and were 7 mm deep. These also included, therefore, the resection of the lingual cortical bone wall. In the center of all these 32 bone defects, Brânemark fixtures with a diameter of 3 mm and a length of 10 mm were implanted. Every implant was primarily stable due to the fixation in the native bone under the created defects. In each mandible site, one bone defect was filled with autologous bone resulting from the previous defect preparation. Half of the defects were covered with a PDS membrane, and the other half were covered only by the relocation of the mucoperiosteal flap. During the observation period of 90-180 days, continuous clinical and radiological controls were executed. Aside from the observed clinical healing problems in the test sites, such as exposure of the membranes and serious inflammatory reactions, the histological and radiological results of the control group regarding bone regeneration were superior to these of the test group, which were valid also for the subgroups with or without autologous bone fillings.

下顎角部外骨症が原因で口底部に炎症症状が発現した１例

We present a very rare case of an exostosis at the mandibular angle associated with inflammatory symptoms of the oral floor caused by sialolithiasis of the submandibular gland. A 52-year old woman was referred to our clinic in March 1993 because of tenderness at the left mandibular angle. At presentation, clinical examination revealed diffuse swelling at the left side of the oral floor. Radiographically, there was a radiopaque image inside the left mandibular angle. It appeared to be a salivary stone, and it was impossible sialographically to depict the mandibular gland because of an obstacle at the salivary duct. A computed axial tomogram obtained parallel to the mandibular plane revealed a dense bony oval mass contiguous with the lingual cortical bone of the mandible behind the submandibular gland. Magnetic resonance images showed that the submandibular gland was dislocated because of pressure applied by the bony mass. Surgical excision of the mass, measuring 10×8×7mm, was performed with the patient under general anesthesia. The pathological diagnosis was not an osteoma but an exostosis of mandibular bone. Postoperative sialography depicted a normal submandibular gland without inflammation. The inflammatory signs and symptoms around the submandibular gland were apparently caused by pressure applied by the exostosis.

Relationship between facial types and tooth and bone characteristics of the mandible obtained by CT scanning.

The purpose of this study was to evaluate relationships between morphological characteristics of vertical sections of the mandibular body and facial type. Of the correlation coefficients between tooth and bone inclination and facial type parameters, facial height index (FHI) was negatively associated with second premolar (P2), first molar (M1), and second molar (M2) inclinations. The angle represented by Frankfort horizontal plane to mandibular plane (FMA) was negatively associated with bone inclination of the M2 section. The buccal cortical bone was thicker in short-faced individuals than in the average and long-faced groups, while lingual cortical bone thickness of the M1 and M2 sections was greater. The basal cortical bone thickness of the L1 section was greater in the short-faced group, and the inclinations of the P2, M1, and M2 axes were significantly smaller. Teeth in the short-faced group inclined more lingually than in the average- and long-faced groups. The results of this study provide evidence that a significant but complex relationship exists between structures of the mandibular body and facial types. The morphological features that relate to masticatory function and facial types are associated with cortical bone thickness of the mandibular body and the buccolingual inclination of the first and second molars.

Morphological Characteristics of Vertical Sections of the Mandible Obtained by CT Scanning.

The external structure of the mandible is not only under the control of genetic factors, but is also influenced by biomechanical factors such as the masticatory muscles. As is well known, one of the characteristics of the morphology of the mandible which represents the influence of these factors is the gonial angle. It varies from a low angle with strong masseter development to a high angle with reduced muscle activity. The aims of this study were to investigate the internal structures of vertical sections of the mandibular body and to evaluate the relationship between these structures and the gonial angle.A principal component analysis grouped all cortical thicknesses except for the buccal cortical bone thickness together with large loadings on the ame factor. Buccal cortical bone thickness was more variable than the other variables and showed a different pattern of variation.The gonial angle was associated with buccal and lingual cortical bone thickness in the second molar section, and was also related to the height of the symphysis and the height and width of the second molar section. These results confirmed the relationship between the gonial angle and the size of the mandibular body at the second molar region.This study provided evidence that masticatory function influenced on both the internal structure and the size of mandibular body.

Radiographic study of bone loss of mandibular lingual cortical plate accompanied by third molar development

The purpose was to determine the features of mandibular lingual cortical bone loss around the root of the mandibular third molar. We examined occlusal radiographs in 2210 persons aged 11 to 78 years. Prominent increase of incidence of bone loss was evident in subjects in their third decade compared with those in their second decade. The incidence was not decreased into the sixties. The incidence of bone loss in men was significantly higher than that in women. The incidence was not influenced by inflammation around the tooth crown of the third molar, by tooth caries, or by metal fillings present in the third molar. The present observations suggest that bone loss is induced by physiologic processes that accompany root formation of the third molar after mandibular growth.

High resolution computed tomography of the inferior alveolar and lingual nerves

Coronal and axial high resolution computed tomography of the mandible extends facilities in dentoalveolar surgery. Preoperatively the relationship between the mandibular canal and the roots of deeply displaced third molars can be determined precisely. After surgical removal of lower wisdom teeth iatrogenic defects of the lingual cortical bone can be detected. The additional information obtained when compared with conventional radiographs is demonstrated in case descriptions. Indications for this technique, radiation exposure and implications for surgery are discussed.

The New Method for the Mandibular Body Ostectomy

For the correction of mandibular deformities, we use frequently sagittal splitting ramus osteotomy. However, in patients who have good occlussion in the molar region, mandibular body ostectomy should be considered for such cases.To overcome some of disadvantages that mandibular body ostectomy has less bony contact between proximal and distal segments, and difficulty adjusting each segment, we improved this method by preserving lingual cortex via an intraoral approach.After separation of the buccal cortex with a fine osteotome, the lingual cortical bone is preserved by only distal or mesial single vertical osteotomy with a reciprocating saw. This osteotomy at the lingual cortex is carefully done following model surgery and cephalometric prediction.This technique could be used in cases in which good occlusion cannot be obtained by sagittal splitting ramus osteotomy.

Osseous and muscular changes after vertical ramus osteotomy: A magnetic resonance imaging study

Magnetic resonance (MR) imaging was performed about 2 years after vertical ramus osteotomy of 10 patients to study changes in the mandibular condyle, cortical and cancellous bone of the proximal fragment, and muscles of mastication. MR imaging observations of the surgically treated patients were compared with findings in 10 asymptomatic untreated control subjects. The results showed that the MR appearance of bone marrow of the mandibular condyle was normal in all patients and in all control subjects. No MR evidence of avascular necrosis of the mandibular condyle was found. MR imaging artifacts from microscopic metallic particles were seen in all surgically treated regions. Thickening of the buccal and lingual cortical bone with narrowing of the bone marrow space was seen bilaterally in eight patients and unilaterally in two patients. Slight medial tipping of the mandibular condyle was seen unilaterally in two patients. Atrophic changes with decreased muscle volume and fatty replacement of muscle tissue was seen unilaterally in eight patients. None of these alterations were seen in the control subjects. MR imaging appears to be an excellent method to study morphologic changes of the muscles of mastication and osseous fragments after orthognathic surgery of the mandible. Thickening of the cortical bone and narrowing of the bone marrow space of the proximal fragment was frequently seen after vertical ramus osteotomy of the mandible and most likely represents remodeling associated with normal healing.