Periodontal healing in humans using anorganic bovine bone and bovine peritoneum-derived collagen membrane: a clinical and histologic case report.

The authors report the clinical and histologic data on the healing of a severe periodontal lesion obtained in a one-walled intrabony defect using anorganic bovine bone under a bovine peritoneum-derived collagen membrane. Eight months after surgery, a bone-like tissue replaced the lost tissues. A biopsy of this tissue was carried out. In the part of the specimen closer to the residual bony wall of the original defect, anorganic bone particles (ABP) appeared to be surrounded by a layer of newly formed bone; its osteocyte lacunae were colonized by osteocytes from the host, and actively secreting osteoblasts were observed in many microscopic fields. No resorption phenomena were observed in the ABP Newly formed cementum with actively secreting cementoblasts was present on the tooth surface, and well-oriented fibers inserting in both newly formed cementum and bone were observed. In an area far from residual bone, all ABP did not appear to be surrounded by newly formed bone. Osteocytic lacunae appeared not to be colonized by cells, and ABP was surrounded by dense connective tissue without osteoblasts near the grafted particles. A very limited amount of newly formed bone, without relations with ABP, was observed close to the root surface. From a clinical point of view, anorganic bone in association with a collagen membrane can be effective in the treatment of bony defects characterized by an unfavorable architecture. From a histologic point of view, the clinical appearance of bone regeneration is not always confirmed in the part of the defect far from the bony walls.     

The histologic evaluation of the implant interface with heterograft and allograft materials--an eight-month autopsy report, Part II.

This paper presents post mortem histologic specimens of the implant/osseous tissue interface from a patient who had had simultaneous bilateral maxillary sinus augmentation and root-form implant placement eight months prior. Two implants were observed: One implant was totally submerged in bone and graft material (2E), and other implant (3E) was devoid of bone at the apex. Microscopic examination revealed that a bony interface existed around implant 2E but that implant 3E had minimal bony interface. It is suggested that the minimal bony interface was the result of minor implant movement induced by variations in barometric pressure on the apex of implant 3E, and that eight months would not have been enough healing time prior to loading for this patient.     

Bilateral maxillary duplication: case report and literature review

Accessory maxillary jaws are extremely rare occurrences. Currently, there is only 1 report of bilateral accessory maxillary jaws in the English-language literature. We present a case of a 7-year-old girl with bilateral bony exostoses extending from the maxillary tuberosities. The patient also had restricted protrusive and lateral excursive movements of the mandible. The histologic report revealed teeth in various developmental stages within the bony exostoses. We concluded that these structures were an isolated form of bilateral accessory maxillary jaws.     

Matrix metalloproteinases and their inhibitors in bone remodelling following distraction osteogenesis of the sheep mandible.

AIM: Matrix metalloproteinases (MMPs), together with their tissue inhibitors (TIMPs), are responsible for the controlled degradation of collagen and other matrix substrates in bone and other tissues. This study evaluated the expression of MMPs and TIMPs in bony remodelling in a bilateral sheep mandible model up to 12 months following lengthening by distraction osteogenesis. METHODOLOGY: Sheep mandibles were harvested 3, 6, 9 or 12 months following lengthening by bilateral mandibular distraction (1 mm/day for 20 days). Undistracted sheep mandibles were used as controls. The tissues underwent routine histology and immunohistochemical staining with monoclonal antibodies specific to MMPs 1-3 and TIMP-1, 2. Matrix and cell staining was assessed using a semi-quantitative analysis. RESULTS: Matrix metalloproteinases and their tissue inhibitors (TIMPs) expression levels were marked at 3 months and decreased thereafter becoming similar to undistracted controls by 12 months. The histologic development of mature lamellar cortical bone was similar to undistracted controls by 9 months following distraction. CONCLUSIONS: A temporal expression of MMPs and TIMPs was found in distraction osteogenesis. MMPs and TIMPS may, in part, reflect the state of bony remodelling following mandibular lengthening by distraction osteogenesis. Matrix metalloproteinases and TIMP expression were comparable to undistracted controls by 12 months, suggesting that equilibrium had been achieved and that bony relapse is unlikely.     

Mucoepidermoid carcinoma in the mandible: Findings of panoramic radiography and computed tomography

Six patients with mucoepidermoid carcinoma in the mandible were studied with both panoramic radiography and computed tomography. Lesion shape and margin were evaluated on panoramic radiography, and bony expansion and cortical plate destruction were evaluated on computed tomography. In addition, a possible correlation among radiographic findings, histologic findings, and prognosis was investigated. Lesions found on panoramic radiography were classified into three types; each type pertained to two of the six patients. The lesion types were as follows: cystic, characterized by a large, cystic radiolucent area; rarefying, characterized by rarefying changes of the trabeculae; and infiltrative, characterized by a central ill-defined area of bony destruction. The results show that computed tomography is useful in the identification of tumor extent, bony expansion, and cortical plate destruction resulting from tumors. None of the patients whose lesions were of the cystic or rarefying type showed evidence of disease after surgery. In contrast, both of the patients whose lesions were of the infiltrative type died of their tumors. Histologic findings of the cystic and rarefying types showed tumors that were well-differentiated or moderately well-differentiated, whereas findings of the infiltrative type showed poorly differentiated tumors. Radiographic findings correlated with histologic findings and prognosis of mucoepidermoid carcinoma in the mandible in this limited series.     

Histologic evaluation of immediate versus delayed placement of implants after tooth extraction.

OBJECTIVE: Full osseointegration is necessary to achieve long-term success of dental implants. We aimed to find out the relative merits of immediate and delayed insertion of implants after dental extraction. STUDY DESIGN: We completed a histologic and histomorphometric examination of the tissue adjacent to delayed and immediate implants in 8 beagle dogs. In 4 dogs, implants were inserted immediately after the extraction of second premolars; in the remaining 4, the implants were inserted 6 months after the extraction. Fluorochrome bone markers were injected on 2 occasions before the dogs were killed 8 months after the implants had been inserted. Each implant and its surrounding tissue was examined macroscopically and microscopically. Both histologic dynamic and histologic static histomorphometry were used in this analysis. Statistical significance was tested by using the Student t test for paired and unpaired observations, the Dunnett t test, and Fisher's least significant difference method for multiple comparisons. RESULTS: The implants placed immediately had 76% of their surface covered with bone, whereas the implants placed after bony healing had 81% of their surface covered with bone. The fibrous tissue at the cervical end of the implant was more dense; the delayed implants also had a greater number of adhesive epithelial elements (hemidesmosomes). Use of dynamic and static histomorphometry revealed no significant differences between the 2 groups. CONCLUSION: We found new soft and hard tissue around dental implants 8 months after their insertion in both groups. Pseudoankylotic healing was seen in the osseous part. The lower level of osseointegration in the immediately placed implants was attributable to the early resorption of bone in the crestal part, resulting in a larger part of the implant being surrounded by soft tissue.     

Mandibular bone deficit with a histologic study in man

The aim of this study was that to determine the clinical and histologic results of a new hydroxyapatite, with innovative properties compared with the other alloplastic materials used in the regenerative treatment of grade 3 bony defects of the mandibular furcations in the human. The hydroxyapatite used in our research is characterized by a scarce density and crystallinity, while from a microstructural point of view, the granules have nanometric dimensions (0.05-0.1 microm). The patient reported here by the authors had a grade 3 infrabony defect into a mandibular furcation. The surgical procedure used consists of the creation of a flap, roots planing, the conditioning of the roots with tetracycline HC, the accurate positioning of the granules of the hydroxyapatite in the furcation area, the crown replacing of the flap, and finally the suture of the same. Six months after the insertion of hydroxyapatite, the clinical effect was studied, comparing the variations found in probing the insertion of depth. At the end of the treatment, a block section of the molar was performed, with part of the surrounding soft tissues, whose histologic analysis underlined the moderate and initial formation of bony tissue, periodontal ligament, and radicular cement in the middle and lower portion of the furcation. In light of these results, the authors conclude that the use of this new hydroxyapatite is promising in the treatment of the mandibular furcations in the human, even if it will be necessary to continue to test its effectiveness through more studies.     

The use of bone morphogenetic protein gene therapy in craniofacial bone repair

Bone morphogenetic proteins (BMPs) are capable of inducing endochondral bone formation when applied on biologic carriers in numerous mammalian in vivo assay systems. Bone morphogenetic protein gene therapy is also currently being developed to promote osteogenesis for clinical indications such as spinal fusions, craniofacial bone loss, and osteoporosis. In this study, critical-sized mandibular defects were treated with a control adenoviral vector (Ad-beta-gal), a BMP-2 adenoviral vector (Ad-BMP-2), or a BMP-9 adenoviral vector (Ad-BMP-9). Gross tissue examination, radiographic analysis, and histologic analysis demonstrated significant bony healing in the BMP treated groups compared to controls. Osteogenesis was limited to the bony defect, without extension into the surrounding soft tissues. The study suggests that with further development, BMP gene therapy may be potentially useful for repair of bony defects in the craniofacial region.     

Subpontic osseous hyperplasia: a case report.

Subpontic osseous hyperplasia is an ectopic growth of bone occurring on the edentulous ridge beneath a fixed partial denture replacing a mandibular first molar. A 56-year-old woman experienced an enlargement of the hard and soft tissues beneath the pontic region of a fixed partial denture replacing her mandibular left first molar. Following removal of the fixed partial denture, the bony enlargement was surgically removed, and the bony fragments were submitted for histologic analysis, which demonstrated mature lamellar bone and appositional growth. One year postoperatively, there has been no recurrence of the lesion. The possible etiologies and treatment modalities are reviewed and a rationale for treatment is presented.     

Histologic Grading of TMJ Tissues in Internal Derangement

Although the spectrum of degenerative TMJ disease has been characterized in previous studies, there have been few specific histopathologic studies offered. The object of this study is to characterize histologically the changes observed in TMJ arthroplasty biopsy material. Forty-one patients with TMJ pain that was not amenable to conservative therapy had conventional TMJ arthroplastic surgery. Biopsy material included the bony eminence, the posterior attachment and the disk proper. The major histologic criteria included perivascular inflammation, synovial membrane thickness and metaplastic changes of the disk and the bony eminence. With these criteria, surgical specimens were graded 0 to 6 with 6 representing the most severe degeneration. In all 41 cases, histologic change was noted to some degree and, therefore, appears to be representative of temporomandibular joint internal derangement.     

Use of preformed hydroxylapatite blocks for grafting in genioplasty procedures

Dense hydroxylapatite is a synthetic, biocompatible, immunologically inert material that can establish a chemical union with bone when placed in intimate contact in histologic studies. The following is a preliminary report of the use of preformed dense, non-resorbable hydroxylapatite blocks as a grafting material for use in advancement and vertical lengthening of the bony chin associated with orthognathic surgical procedures. In rare instances where an autogenous bone graft would be required for vertical lengthening without any advancement of bony pogonion, the need is obviated by utilization of the hydroxylapatite solid block.     

全身因素影响骨缺损修复的组织学评价

目的：为明确全身因素对牙槽骨修复的影响，方法：２４条狗上的颌尖磨牙间隙区制备一定大小的二壁骨袋，随机分４组，采用组织学常规检查，结合胶原特殊染色和图象分析。结果：正常对照组骨修复块，２个月已基本完成，甲状腺素组骨质形成明显减少，骨高度明显降低（Ｐ〈０．０１）。卵巢切除组和实验性糖悄病组可见骨成熟明显减慢，骨小梁稀疏，空隙率高（Ｐ〈０．０５），意义：客观地评估了全身因素对牙槽骨修复的调控作用，国阐明     

Congenital monostotic fibrous dysplasia--a new possibly autosomal recessive disorder.

Two siblings, a 3-month-old white male infant and a 12-day-old female infant, had an anterior mandibular bony lesion that, in both cases, had been present at birth. After evaluation of clinical, physical, radiographic, laboratory, and histologic findings, a diagnosis of congenital monostotic fibrous dysplasia was made. Thorough review of the literature on fibrous dysplasia yielded no similar cases. The two cases presented appear to be the first reported examples of congenital monostotic fibrous dysplasia in siblings. The parents said there was no consanguinity. The possibility of a new autosomal-recessive disorder is likely.     

Age changes in the human frontozygomatic suture from 20 to 95 years.

The frontozygomatic suture of human cadaver material was examined by a combination of histologic, radiographic, and gross tecniques to determine the aging changes in the suture and the approximate age at which sutural fusion occurs. The sample consisted of sixty-One specimens of human beings ranging in age from 20 to 95 years. Observations were made on specimens at age intervals of 5 years. Since the frontozygomatic suture is bilateral, one suture from each specimens was used for radiographic and gross examination for synostosis, and the opposite side was subjected to histologic analysis. The findings of this study have lead to the following conclusions: 1. The human frontozygomatic suture undergoes synostosis during the eigth decade of life, but does not completely fuse by the age of 95 years. 2. Synostosis is a progressive process which commences as small areas of bony union that occur initially within the internal portion of the suture and then progresses to the orbital perisosteal surface. Bony union is not found at or near the facial periosteal surface. 3. The bony surfaces of the frontozygomatic suture become increasingly irregular with advancing age as a result of the formation of projections or interifitations=     

A novel experimental model for studying transverse orthodontic tooth movement in the rat mandible

Objectives:To establish a rat model of a one-piece mandible using the principles of gingivoperiosteoplasty and guided bone regeneration to fuse the midline symphyseal area.Material and Methods:Twenty-four Sprague-Dawley female rats were divided into two groups: 12 experimental and 12 control. Both groups were imaged using in vivo micro-computed tomography at baseline and at end point (5 months). The experimental group received regenerative surgery at the symphysis area; the control group received no treatment. Outcomes were evaluated by radiographic examination of gross and volumetric bony changes in the symphyseal region of interest marked between the mental foramina bilaterally and the two central incisors near the most coronal margin of the alveolar crests. These landmarks were chosen as they can be reproduced on the computed tomography images at baseline and end point. Histologic examination was performed on all samples at a level 5 mm apical to the alveolar bone crest.Results:Radiologic and histologic examinations of the experimental group revealed complete bony fusion of the symphyseal area in three subjects, partial fusion in five subjects, and thickening of the alveolar bony socket in three subjects; one rat died of anesthesia-related complications. No evidence of fusion or alveolar bone thickening was found in any of the controls.Conclusions:This surgical animal model demonstrates that a rat mandible can be surgically manipulated to mimic the one-piece human mandible. This novel model may prove useful in studying mandibular bone remodeling and orthodontic mandibular tooth movement.     

Repair of a critical size defect in the rat mandible using allogenic type I collagen.

Mandibular fractures, resulting from either trauma or reconstructive surgery, can be challenging craniofacial problems. The morbidity of failed fracture healing is significant and may require bone grafting. Donor site morbidity and finite amounts of autogenous bone are major drawbacks of autogenous bone grafting. Similarly, the use of allografts and xenografts may be associated with an increased risk of rejection, infection, and nonunion. To circumvent the limitations of bone grafting, research efforts have focused on formulating a suitable bone substitute. The purpose of our study was to evaluate the efficacy of type I collagen implants in repairing critical sized mandibular defects in rats. Twelve male Sprague-Dawley rats (200-300g) were divided equally into control and experimental groups. Full thickness, round, four millimeter in diameter defects were created in the ramus of the right mandible of all rats using an electrical burr at low speed. The defects were irrigated of all bone chips, and either filled with a precisely fitted disk of allogenic collagen type I gel (experimental animals) or left empty (control animals). Animals were killed 6 weeks after surgery and healing of the bone defects was assessed in a blinded fashion using radiologic and histologic analysis. Radiologic analysis of the control group revealed a clear circular right mandibular defect in all animals, whereas the collagen disk implant group revealed an indistinct to nonexistent right mandibular defect in all animals. Densitometric analysis revealed a significant difference between these groups (* P = 0.01). Similarly, gross analysis of control mandibles revealed a 4mm round, soft-tissue filled defect, while implanted defects demonstrated gross bone spanning the defect. Finally, histologic analysis of all control mandibles revealed clearly demarcated bony edges at the defect border with connective tissue spanning the defect. In contrast, histological analysis of all implanted mandibles revealed indistinct bony edges at the defect border with a thin layer of osteoblasts and viable bone spanning the defects. We have demonstrated the ability of type I collagen to promote healing of a membranous bony defect that would not otherwise heal at 6 weeks. The suitability of type I collagen as a carrier matrix provides ample opportunity for tissue-engineered approaches to further facilitate bony defect healing. Promoting bone formation through tissue engineering matrices offers great promise for skeletal healing and reconstruction.     

Repair of surgical clefts of the hard palate in beagles

The biological responses to the repair of palatal clefts has been evaluated principally by monitoring craniofacial growth. Little is known about the regenerative ability of the repaired palate. In the present study, 18 Beagle pups (51 to 58 days old) were assigned to one of three groups: (1) control group, having no surgery; (2) cleft group, having a surgically created cleft of the posterior hard palate (mean bony measurement: 3.1 x 11.7 mm) at 8 weeks of age; and (3) repaired group, same as group 2, and followed by soft-tissue closure at 12 weeks of age. Craniofacial growth was monitored by cephalometric and dental cast measurements. Records were taken at 6-week intervals. Animals were sacrificed either 16 or 28 weeks after time of cleft creation. Routine histologic examination and histochemical detection of alkaline phosphatase activity were performed to examine the quality and extent of soft-tissue repair and bone formation. Analysis of the cleft palate group revealed that the size of the bony cleft increased with time. The histologic examination demonstrated at 24 weeks of age (12 weeks after the repair) active reduction of medial margin of the bony palate as evidenced by osteoclastic activity. At 36 weeks of age, neither osteoblastic nor osteoclastic activity was detected. The mean dimensions of the bony cleft, in the cleft group at 36 weeks, were 7.9 x 18.8 mm. In the repaired group, partial bone repair occurred. However, no consistency was seen in predicting extent or location of repair. Histochemical detection of alkaline phosphatase activity indicated that the repaired group had greater amounts of new bone formation. In some sites, suture regeneration was seen. As with the amount of bone formation, the amount of suture regeneration was variable. This study revealed that the presence of a cleft inhibits osteoblastic activity along the margin of the cleft, and there is limited potential for regeneration of the palate subsequent to the repair.     

Sclerosing osteomyelitis of Garré periostitis ossificans

Sclerosing osteomyelitis of Garré is a rare syndrome; the mandible is the most commonly affected bone segment in the cervicofacial region. This chronic disease is characterized by a nonsuppurative ossifying periostitis with subperiosteal bone formation, commonly reactive to a mild infection or irritation. The differential diagnosis must be made with similar clinical conditions with hard mandibular swelling associated with bony sclerosis. Presumptive diagnosis can be achieved by radiology, but such diagnosis must be confirmed by histology. The aim of therapy is to remove the cause when recognized, aided by an adequate antibiotic therapy. Clinical, radiographic, and histologic features are presented in this case report.     

The postoperative maxillary cyst: report of 71 cases

The postoperative maxillary cyst develops as a delayed complication many years after surgical intervention in the maxillary sinus. The clinical, radiographic, surgical, and histologic findings of 71 such cysts are described. The cysts occurred most frequently ten to 30 years after radical operations. The most common symptoms were swelling or pain of the cheek and the mucogingival fold of the maxilla. Radiographically, the lesions were either unilocular or multilocular, and bony perforation was noticed in half of them. The cysts were treated surgically in all cases. Most of them had a thin wall, lined with ciliated columnar epithelium. The results of our analysis and possible pathogenesis are discussed.     

The diagnostic value of subtraction radiography in the assessment of granular hydroxylapatite implants

Although histologic analysis of osseous changes around hydroxylapatite (HA) implants can be highly accurate, it is of limited use in human beings. Digital subtraction radiography may provide a noninvasive alternative. Ten patients with bony lesions were operated on and nine of the iatrogenic defects were filled with granulated HA. In one patient, the defect was left unfilled for reference. Customized film holders provided standardized radiography. Follow-up images after 4 to 6 months were subtracted from immediately obtained postoperative images, and changes around the implants were noted. From ten pairs of radiographs, eight could be successfully subtracted, whereas two pairs required corrective image transformation before subtraction. Although no bone loss was observed in any of the patients, the implants did not appear to enhance physiologic bone regeneration either. Hence, subtraction radiography holds the potential of clinical utility for the follow-up of HA implants. However, technical improvements are necessary to yield quantitative data.