Healing of bony defects in the irradiated and unirradiated rat mandible.

A model system of the irradiated rat mandible has been developed and used in conjunction with a non-spontaneously healing mandibular defect. The contribution of the tissue components in the healing of bony defects was studied using demineralized bone powder (DBP) prepared from unirradiated or in vivo irradiated rat long bones. Better bony fill of the defects occurred in the irradiated beds filled with unirradiated DBP than in the unirradiated beds containing irradiated DBP. This suggests that, at least in the early postirradiation period, the bed is not the limiting factor in healing of bony defects and the osteogenic components of bone in the DBP may be most affected by irradiation. In the irradiated bed, the defects grafted 2 weeks after irradiation healed better than those grafted at 4 weeks. Thus, the timing of surgery after irradiation also plays a role in the healing process, with early surgery producing better results.     

Osseous healing of the sagittal ramus osteotomy: a histologic comparison of rigid and nonrigid fixation in Macaca mulatta.

Twenty-three adult female rhesus monkeys underwent advancement of the mandible by the sagittal split ramus osteotomy. Twelve had the proximal and distal segments wired together and underwent 6 weeks of maxillomandibular fixation (MMF). Eleven animals had bicortical bone screws placed between the segments and no postsurgical MMF. The animals were killed at 6 and 12 weeks and the osteotomy sites were prepared for histologic examination. Overall, the results showed that the two groups of animals underwent markedly different patterns of osseous healing. The osteotomy sites in the MMF animals were filled with callus, which then formed bone. In contrast, no callus was found in the majority of the rigid fixation osteotomy sites; direct bony deposition was found instead. The results of this investigation show that, like long bones, the sagittal osteotomy can heal by direct or indirect means depending on the rigidity of the fixation.     

Autogenous platelet-rich plasma in combination with bovine-derived hydroxyapatite xenograft for treatment of a cystic lesion of the jaw

In the last 5 years, many studies about autogenous platelet-rich plasma have been undertaken pointing out its regenerative and reparative properties on tissues. The features of this product are an attribute of platelet cells, which, after cellular interactions, release growth factors. These molecules promote tissue healing and also induce cellular regeneration. Bone is a dynamic tissue subject to balanced processes of bony formation and reabsorption; autologous platelet gel or concentrate (PRP) can be used alone or in association with bony graft for the treatment of bony defect, cystic lesions, alveolar bone defects, and periodontal pockets. Its application fields are oral and maxillofacial surgery, plastic surgery, and general surgery, and it can be applied particularly in patients with coagulation diseases. In our experience, a giant cystic lesion of the jaw was treated with PRP and granules of bovine-derived hydroxyapatite xenograft to enhance bony regeneration and promote tissue healing.     

Piezosurgery: an ultrasound device for cutting bone and its use and limitations in maxillofacial surgery

Piezosurgery uses modulated ultrasonic vibration to allow controlled cutting of bony structures. Delicate bony structures can be cut easily and with great precision, without destruction of soft tissue. We have found this device useful when exact cutting of thin bones is essential. However, it is of only limited use in cutting thick bones and in regions with limited access.     

Qualitative and quantitative expression of bovine bone mineral in experimental bone defects. Part 1: Description of a dog model and histological observations

BACKGROUND: The purpose of this study was to evaluate histologically the contribution of inorganic bovine bone biomaterial in a new experimental bone defect in dogs at different healing periods and to examine newly formed bone around the grafted mineral particles and their relationship in membrane-protected (test) and non-protected intrabony (control) defects. METHODS: Four round intrabony defects, 5 x 4 mm were made bilaterally (at different times) on the lateral bony mandibular angle in eight dogs. Two defects were filled with bovine bone mineral (BBM) particles and two remained non-grafted but were blood clotted. A collagen membrane covered each defect type (n = 4). This procedure was repeated on the contralateral side at a different given time to obtain two different healing periods in each dog. Thus, four specimens were obtained at 3, 6, 12, and 24 months postoperatively for each healing period. The non-decalcification method (Donath technique) with Stevenel's blue and van Gieson's picro fuchsin staining was used for histological examination. RESULTS: Newly formed bone was observed at all examined defect types. The BBM particles were clearly evident regardless of the healing period. At 3 and 6 months, newly formed bone, woven in nature, was incorporated with the grafted particles. High cellular bone with occasional osteoclasts was noted towards the surface of the mineral particles. No substantial difference was observed between the protected and the non-protected defects except for higher ossified centers around the membrane-protected defects. At the non-grafted sites, the membrane-protected defect showed newly formed bone near the bony walls, and particularly under the membrane, establishing a bony bridge over the defect at the healing periods. The non-grafted unprotected defect (control) showed bone formation only at the base and close to the bony walls leaving a healed concave configuration. At 1 and 2 years, the grafted sites showed full bone healing configuration. However, the grafted particles still dominated the previous defect area and were completely surrounded by the newly formed bone. Osteons and lamellar bone arrangement were established but the bone was still highly cellular and osteoclasts could still be identified. The non-grafted membrane-protected sites showed excellent bone healing although areas of non-mineralized soft tissue were often seen. The control sites healed but still presented with a concave surface configuration. CONCLUSIONS: BBM biomaterial is a highly osteoconductive material. In a 4-wall bony defect, newly formed bone was well evident in establishing excellent bone healing configuration with or without a regenerative biological barrier. The grafted material dominated the experimental sites with no substantial resorption at any healing period up to 2 years observation.     

An evaluation of bone healing in cavities in the jaws implanted with a collagen matrix.

Bony defects in the jaws after surgery may show poor healing especially in the maxilla and the area may never completely be replaced by bone. 50 patients with pathological bony cavities in the jaws were used to assess the efficacy of a collagen matrix implanted into the treated bony defect and 50 patients in whom no material was implanted were used as controls. The results were assessed radiographically at 3, 6 and 12 months. At 3 months, bone deposition in the control group was in advance of the implanted group, but after 6 and 12 months healing appeared to be similar in both groups. No adverse effects were found due to the presence of the collagen implant. Collagen delayed the early osteogenic healing period, indicating that only when it has been resorbed can the area heal with osteogenic granulation tissue. As some radiolucent areas still remained in the healed implant group after 12 months it must be assumed that the collagen implant has only been replaced by host fibrous tissue and therefore does not possess osteoinductive properties.     

输送盘牵张成骨重建颅颌面骨缺损的研究进展

输送盘牵张成骨已成为重建人类长骨大范围组织缺损极为有效的方法之一.用其也可高效地重建颅颌面骨因创伤、肿瘤术后、骨髓炎以及骨愈合不良等造成的大范围骨组织缺损.本文就输送盘牵张成骨在颅颌面骨缺损重建的应用作一综述.     

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.     

Healing of a sinus tract of periodontal origin.

A sinus tract adjacent to teeth is usually considered to be of endodontic origin and root canal therapy is the primary treatment to achieve healing. A case of a sinus tract is presented in which a suspected endodontic-periodontic lesion was successfully treated by periodontal therapy alone. The sinus tract healed and the radiograph showed bony repair.     

Symphysis menti of the rabbit: anatomy, histology, and postnatal development.

A histologic and anatomic investigation of the symphyseal region in rabbits did not reveal a bony fusion between the two halves of the mandible; these two bones are united in the anterior part by a synchrondrosis, and a definite histologic suture with interdigitating bony rugosities and interposed connective tissue, in the posterior part. Functionally, the two parts are immobile and thus constitute one bone.     

The effect of a bioresorbable matrix barrier in endodontic surgery on the rate of periapical healing: an in vivo study

The purpose of this prospective clinical study was to assess the rate of healing of periapical bony defects created at the time of endodontic periapical surgery by measuring the densitometric ratio change in periapical osseous tissues, after periapical endodontic surgery was performed, by using or not using Guidor bioresorbable membrane material. Periapical surgeries were performed on 25 patients where nonsurgical root canal therapy had failed and a periapical lesion was present. For inclusion in the study, the osseous defect to be analyzed had to be confined to the apical area, with bone covering the entire root surface coronally, and an intact lingual cortical plate had to be present. A series of radiographs at the 3-, 6-, and 12-month recalls were compared with the radiograph taken immediately after surgery by using digital imaging and a densitometric ratio that gave a numerical estimation of osseous healing. Using repeated-measure ANOVA, it was shown that there was no statistical difference between the rate of healing in those cases where a Guidor resorbable membrane was used and those cases where no membrane was used. The results suggest that placement of a guided tissue membrane over the bony opening created during an endodontic periapical surgical procedure has no beneficial effect on the rate of healing and the added expense to the patient would not be warranted in these cases.     

胶原蛋白在咬肌附着及再附着界面的表达

目的　探讨山羊咬肌与下颌骨皮质骨面和松质骨面再附着中胶原在肌-骨界面的表达及意义。方法　以9只成年山羊为研究对象,其中1只为正常对照。将实验组山羊双侧下颌骨咬肌附着从骨面剥离,附着区骨面平均分为二部分,分别保留原骨面或去除皮质骨,暴露松质骨,咬肌原位缝合。术后2、4、8、12周采集标本,采用免疫组织化学ABC法检测两种肌-骨界面Ⅰ、Ⅱ、Ⅲ型胶原的表达情况。结果　免疫组化观察表明,Ⅰ、Ⅱ、Ⅲ型胶原在愈合过程中的表达不同,但两种骨面的肌-骨界面胶原表达无明显差别。结论　再附着界面胶原表达随时间变化而与附着骨面结构无关。     

Interimplant papilla preservation in the esthetic zone: a report of six consecutive cases

Simultaneous removal of multiple adjacent teeth in the anterior maxilla often leads to collapse of the labial bony plate as well as flattening of the interproximal bony scallop, resulting in long implant restorations with missing interimplant papillae. An interimplant papilla preservation technique involving alternate immediate implant placement and provisionalization, one following the osseointegration healing period of the other, was introduced. All 14 implants placed in six consecutive patients maintained osseointegration after a mean functioning time of 22.6 months (range 12 to 34 months). A highly satisfactory esthetic outcome and a papilla index score of 3 was observed in all patients.     

Barrier membrane and bone graft treatments of dehiscence-type defect at existing implant: a case report

Dehiscence-type bony defects may occur after implant application because of microbial action as well as of biomechanical and occlusal overload. The aim of the treatment of a periimplant defect is to arrest the progression of the bone loss and to achieve a maintainable site for the implant. In these situations, barrier membranes and bone graft materials can be used to achieve complete bone healing around dental implants. Bone regeneration is possible in a periimplant bony defect of a functioning implant if the proper surgical technique is utilized and the etiologic cause is eradicated. This study presents the surgical coverage of a periimplant bony defect around an implant that was inserted 7 years ago. The surgical correction was made using a barrier membrane in conjunction with bone graft materials. A follow-up of 6 months seemed to reveal radiographic bone regeneration.     

Effect of hydroxylapatite, tricalcium phosphate, and collagen on the healing of defects in the rat mandible

The effects of hydroxylapatite and tricalcium phosphate alone or mixed with collagen on the repair of surgically created bony defects in the mandible of 30 rats were evaluated by gross examination and light microscopy. When specimens were examined 4 and 12 weeks after placement of the implants, bone was observed in direct contact with the implants at the periphery; however, in the central portion of the defects, the implants were surrounded by fibrous connective tissue containing macrophages and a few multinucleated giant cells. Neither the hydroxylapatite or the tricalcium phosphate induced bony healing in the defect, and the addition of collagen did not interfere with healing. Because collagen does not alter healing, it might be possible to use it as biocompatible resorbable binder to confine particulate ceramic implants and inhibit their migration.     

Hard tissue volume stability of guided bone regeneration during the healing stage in the anterior maxilla: A clinical and radiographic study

Background

Guided bone regeneration (GBR) is currently the most widely used technique to reconstruct localized peri‐implant bone defects.

Objectives

To evaluate hard tissue volume stability during the healing stage of GBR with particulate bone graft and resorbable collagen membrane.

Materials and methods

Twenty‐eight patients who were missing a single maxillary incisor and required implant placement combined with GBR were randomly assigned to 2 groups: submerged (n = 14) and transmucosal (n = 14) healing groups. Cone‐beam computed tomography (CBCT) was performed before, immediately after and 6 months post‐surgery. The 3 sets of CBCT data were three‐dimensionally reconstructed and superimposed. Horizontal hard tissue alterations at different vertical levels were recorded. The relative position and distances from the boundary line of the bony defect envelope to the outlines of the augmented ridge were determined immediately post‐augmentation and 6 months after healing.

Results

Augmented ridge underwent horizontal volume reduction during the healing period. Vertical levels (P = .000) rather than healing strategies (submerged or transmucosal) (P = .182) had statistically significant impacts on the reduction width. The boundary line of the ridge defect envelope located within the bony profile immediately after surgery, but outside of the bony profile after 6 months.

Conclusions

GBR with resorbable membrane and particulate bovine bone would undergo horizontal volume reduction during the healing stage. New bone formation at the coronal site may only be predictable within the bony envelope.     

Garre's osteomyelitis: a case report

Garre's Osteomyelitis is a distinctive type of chronic osteomyelitis associated with gross thickening of the periosteum of the bones and peripheral reactive bone formation resulting from mild irritation or infections. The condition is seen exclusively in children or young adults. Mandible is more often affected than the maxilla. Clinically it manifests as bony hard, non-tender swelling which is slowly progressive and associated with painful carious tooth. In this article, a case report of a eight year old female is presented along with complete investigations and treatment.     

Resorption of the zygomatic arch after elevation of a depressed fracture and subsequent osteomyelitis: report of case.

A case of osteomyelitis of the zygomatic arch with complete resorption has been presented. The cause of osteomyelitis of the facial bones was discussed. Infection of the soft tissue after intraoral elevation of fractured zygomas does occur, but rarely leads to osteomyelitis and subsequent bony resorption of the underlying bone. Antibiotics have reduced the incidence of osteomyelitic infections in the past 20 years; however, a vigorous regimen of preoperative and postoperative attention to aseptic technique, proper antibiotics, and close follow-up is required to control these problems.     

Bone apposition in surgical bony defects following orthodontic movement: a comparative histomorphometric study between root- and periodontal ligament-damaged and periodontally intact rat molars

BACKGROUND: The influence of orthodontic tooth movement with diminished periodontal support is unclear. The aim of the present study was to evaluate bone healing in surgical defects following orthodontic tooth movement with and without periodontal ligament (PDL) and root surface damage. METHODS: The study comprised 33 adult male Wistar rats, divided into two groups: group 1 (n = 14) with bony defect and no root damage and group 2 (n = 19) with periodontal bony defect including root/PDL damage on the mesial root of the maxillary first molar. One week after a surgical defect was created, orthodontic protraction of the right maxillary first molar was initiated in both groups. After 2 weeks of protraction, retention of 1 week was established; at the end of this period block sections were made. Histomorphometric analysis through light microscopy of decalcified tissue was performed. Results were statistically analyzed using independent samples t test and analysis of variance (ANOVA) with repeated measures. RESULTS: Differences between groups in total area of bone defect and bone apposition were not statistically significant. Bone apposition calculated as percentage of the bone defect was significantly (t-test) greater (P = 0.002) in group 2 (46.21%) than in group 1 (24.95%). Within each group, area of bone apposition was significantly (ANOVA) greater in the distal than in the mesial quadrants of the bony defect (P = 0.006) and in the apical than the occlusal ones (P = 0.021). CONCLUSION: Following orthodontic tooth movement, periodontal bony defects showed enhanced bony healing compared with alveolar bone defects with no direct association with the periodontal attachment apparatus.     

非血管化骨-人重组骨形成蛋白-2复合种植体同期移植的超微结构观察

目的对于非血管化自体骨移植同期植入种植体,目前仍有争议.近年的研究表明非血管化自体骨植入后,早期即可有新骨形成.本研究旨在探讨非血管化自体骨-种植体同期植入后种植体的愈合过程,并观察骨形成蛋白对与非血管化骨同期植入的种植体愈合过程的促进作用.方法健康犬12只,随机分为2组.在犬双侧下颌角区各截取3cm×4cm骨段,实验组骨段内植入含有重组人骨形成蛋白-2的种植体,对照组植入普通纯钛种植体.植入种植体后,将骨块及种植体植回对侧下颌角,并以不锈钢丝固定.术后2、4、6、8及12周各处死2只动物,标本行扫描电子显微镜观察.结果实验组种植体-骨界面在术后2周即可见明显的新骨形成,术后6～8周,已基本形成骨性结合;术后12周时,可见较为成熟的骨融合.而对照组骨融合在术后6～8周方开始形成,术后12周时仍未完成.实验结果显示,实验组骨融合的时间较对照组至少可提前4周.结论骨形成蛋白的骨诱导活性可以促使种植体在植入后早期与非血管化骨形成骨融合,从而为提高同期植入种植体的成功率提供了新的途径.