Reduction of the compact and cancellous bone substances of the edentulous mandible caused by resorption.

Examination of various bone sections of edentulous atrophic mandibles showed that the body of the mandible loses up to 60% of its original bone substance during progressive atrophy. Most of the bone loss occurs in a relatively early stage of the atrophic process. The greatest extent of bone reduction can be observed in the area of the second premolar and the first molar. In the interforaminal region, which is situated mesial from them, resorption, in most cases, is not as progressive as in the premolar/molar area. The compact and cancellous bone substances are most often equally affected by resorption. Moreover, it could be observed that the cancellous bone substance of extremely atrophic mandibles particularly in the interforaminal region, is marked by a significant increase in density. This might be interpreted as a restructuring process to compensate for bone losses and to secure the stability of the atrophic body of the mandible.     

Homogenous bone grafts to the mandible.

Homogenous bone grafts were used in 20 cases including cysts, nonunions, an open bite, an ameloblastoma, fibrous dysplasia, and cherubism. There was a 75% success rate. This type of graft can solve a number of operative problems in mandibular surgery.     

Desmoplastic fibroma of bone. A case in the mandible.

A case of desmoplastic fibroma of the mandible in a 25-year-old white man, expanding from the first molar to the ramus, is presented. This is a rare primary central neoplasm. It grows expansively and may destroy the cortex. Few cases in the mandible have been reported. Its diagnosis is important because the experience reported by different authors has shown the tendency for recurrence when treatment consists of less than radical resection.     

Variations in bone mass within the cortices of the mandible.

A study of intermandibular variations in bone mass in cortices between regions of the alveolar process and mandibular body and between buccal and lingual cortices in the same region has been carried out. The material consisted of 24 autopsy specimens of half mandibles from normal subjects. Microradiograms of ground sections from incisor, premolar, and molar regions were used. Quantitation of bone mass in percent within the cortices was done by an electronic point-counting system. The analysis indicates that bone mass may lie on nearly the same level all over in the entire lingual cortex. In buccal cortex, bone mass may vary from region to region, as a fall in bone mass from incisor to premolar to molar region in the buccal alveolar cortex, and a rise in bone mass from premolar to molar region in the mandibular body may occur. Bone mass in buccal incisor cortex of mandibular bodies shows great individual variations. Generally, bone mass may lie on a lower level in the buccal than in the lingual incisor and premolar cortec of the mandibular body while bone mass elsewhere lies on nearly the same level in the same part of the two cortices. Bone biopsies should be taken in either the premolar or the molar region of mandibular bodies.     

Variations in structure within the trabecular bone of the mandible.

A study of the intramandibular variations in bone mass, coarseness of the bone trabeculae and bone activity between incisor, premolar, and molar regions has been carried out, as well as estimation of possible differences in these variations between groups of mandibles with different dentition. The material consisted of 24 autopsy specimens of half mandibles from normal subjects. Microradiograms of ground sections from incisor, premolar, and molar regions were used. Quantitation of bone mass was done by an electronic point-counting system. The analysis indicates that (1) the variations in bone mass within same region are marked, (2) trabecular bone is denser and more delicately woven in the incisor region than in either premolar or molar regions, where mass of bone is the same, although there is probably more delicately woven trabecular bone in molar region, (3) bone activity lies on the same level all over in trabecular bone within the mandibular body and (4) the variations of these factors seem to be independent of state of dentition in the single mandible.     

Spontaneous bone healing of the large bone defects in the mandible

Spontaneous healing of large bone defects in the mandibles of 33 patients was studied. Standard postoperative clinical and radiographic examinations were performed immediately after surgery and after 2, 6 and 12 months. They were analysed using a novel relative bone densitometry method and indexes of relative bone healing were established. Spontaneous bone regeneration occurred in all patients clinically, and the computer analysis of radiographs showed that the mean final bone density in the bone defects was 88% of the bone density of the surrounding healthy bone. In the cases of smaller defects (the greatest diameter on panoramic radiographs was 20-30 mm) the final bone density was 97%, while the larger defects finally healed with 84% of the bone density of the surrounding bone. Increased patient age had a negative influence on healing and the shape of the bone defects was more important for healing than their volume. Spontaneous bone healing occurred even in large bone defects in the mandible, therefore this simple treatment with low economic and biological costs should be the treatment of choice, taking into account the patient's age, surgical principles and time of rehabilitation.     

Use of the mandibular staple bone plate in the deformed mandible.

Seven cases have been presented to demonstrate the reconstructive potential and the longevity of the mandibular staple in a variety of unusual cases. The use of the staple provides a surgical method to rehabilitate various types of mandibular deformities. Functional success without major complications has occurred in 90% of cases recently reported.     

Aneurysmal bone cyst of the mandible

Aneurysmal bone cyst is a multilocular cystlike lesion in the bone which is filled with blood. In 1942, Jaffe and Lichtenstein¹ separated a cystic lesion containing numerous pools of blood from other cysts, and in 1950 Lichtenstein² proposed the name “aneurysmal bone cyst” for this entity. He stated that the aneurysmal bone cyst usually occurred in vertebrae, clavicle, rib, and limb bones and produced eccentric bone expansion with numerous pools of blood. The histologic findings showed that spongy bone and marrow were replaced by a fibrous tissue in which hemorrhage, giant cell reaction, and reparative new bone formation were observed.Lichtenstein³ reported statistically that vertebrae and limb bones were commonly affected, constituting about 60% of the total number of cases. Studies by Biesecker et al⁴ and Ruiter et al⁵ showed almost the same result. The aneurysmal bone cyst rarely affects the craniofacial bones. Biesecker reported only two cases in the mandible in 66 cases, and Ruiter reported one case in the maxilla in 105 cases. Daugherty⁶ mentioned that only 2% of these lesions were in the facial bones.     

Aneurysmal bone cyst of the mandible

The case of a 48-year-old male patient with a slowly growing mass in the right molar region of the mandible is presented. The biopsy specimen showed an aneurysmal bone cyst. After radiation therapy failed to arrest the process, the patient was treated surgically via an external approach. Between the time of the initial presentation and the date of definitive surgery 9 months later, a dramatic change was noted in the roentgenographic pattern of the lesion, demonstrating early and late stages in the development of an aneurysmal bone cyst. There has been no recurrence in a 17-year follow-up period.     

Stafne bone cavity in the anterior mandible

Lingual mandibular bone defect, also known as Stafne bone cavity, is mostly seen in the posterior portion of the mandible. Inclusions in the anterior portion are very unusual, with around 50 cases reported in the English-language literature. They are often asymptomatic conditions diagnosed during a routine radiographic examination. This article describes a case of anterior Stafne bone cavity in a 52-year-old man mistaken for periapical pathologic defect and referred for treatment. In addition to clinical examination, the patient was imaged using conventional periapical, panoramic radiography, and computed tomography. Confirmation of the salivary gland tissue in the lingual mandibular defect was made with the histopathologic examination after surgical intervention. The differential diagnoses, treatment choices, and pathogenesis of these bone cavities are also discussed after the case presentation along with the literature review.