Interpositional bone grafts to augment the atrophic mandible

Interpositional or inlay bone grafts have been shown to resorb more slowly than onlay-type grafts. The visor-osteotomy provides an improved mandibular denture-bearing area. New dentures fabricated postsurgically have been routinely successful. Major disadvantages are that the patient will be unable to wear a mandibular denture during the entire healing phase and permanently altered sensation of the mental nerve will usually occur.     

Interpositional bone graft augmentation of the atrophic mandible: a preliminary report.

The mandible is sectioned in an oblique direction and an iliac crest graft is placed between the fragments for augmentation of an atrophied mandible. The technique was used in 12 patients; follow-up examinations included serial panoramic radiographs and recording of changes in mandibular height. A 10% to 27% loss of the height gained occurred between three and 12 months postoperatively.     

下颌后牙区骨皮质厚度对牙种植精度的影响

目的 探讨下颌后牙区局部骨皮质厚度(cortical bone thickness, CBT)对牙种植精度的影响。方法 纳入2020年6—12月间就诊于中国科学技术大学附属第一医院口腔医学中心的下颌后牙区牙种植患者30例,平均年龄43.1岁,共植入种植体37枚。于术后CBCT中测量种植体颈部颊、舌侧CBT并计算均值,将均值分为两组(A组为CBT≥1.5 mm; B组为CBT<1.5 mm)并分析各种植体植入顶点、末端及角度偏差。结果 CBT≥1.5 mm组的牙种植精度在植入顶点、植入末端及植入角度方面均优于CBT<1.5 mm组(P<0.05)。结论 种植区骨皮质厚度较低时,牙种植精度可能降低,因此临床上对于此类患者应更加谨慎对待。     

下颌后牙区骨组织与种植体初期稳定性的相关性研究

目的:研究下颌骨后牙区骨组织结构对种植体初期稳定性的影响。方法:20名患者术前拍摄CT,通过软件SimPlant测量得到种植体周围平均骨密度及种植体颈部骨皮质厚度。共植入24枚种植体,术中植入后即刻用Osstell仪器测量得到种植体稳定系数(ISQ)。所有数据通过SPSS 17软件包进行统计学分析(P<0.05)。结果:种植体颈部骨皮质厚度与ISQ相关(P<0.05),颌骨后牙区骨密度与ISQ无相关关系(P>0.05),性别、年龄与ISQ无相关关系(P>0.05)。结论:术前对下颌骨后牙区骨密度的测量不能预测种植体初期稳定性,种植体初期稳定性与种植体颈部骨皮质厚度相关;与种植体初期稳定性相关的因素还需进一步研究。     

Placement of posterior mandibular and maxillary implants in patients with severe bone deficiency: a clinical report of procedure

The purpose of this investigation was to modify the method for implant placement in the posterior parts of the arches for fixed implant-supported prostheses using minimally invasive surgery. Eighty-six implants were placed posterior to the mental foramina in patients with severely resorbed mandibles, and 75 implants were placed in the posterior severely resorbed maxilla. Bone grafting from the mandible to the maxillary sinus was performed in 9 patients with severely atrophic maxillae. In all patients, optimal use of the anatomic features of the arch was achieved by tilting the implants. Patients were followed up for 12 to 123 months after prosthesis connection (mean 18 months). Three maxillary implants were lost at the time of abutment connection: 1 in the pterygoid plate, 1 close to the posterior sinus wall, and 1 placed in the palatal cortex. One implant was mobile approximately 1 year later, apparently because of an ill-fitting prosthesis. In the mandible, no implants were lost. The method described for the treatment of edentulous arches represents an alternative therapy to several others currently in use. This minimally invasive surgical procedure should be applicable in an outpatient clinic for treatment of severely resorbed posterior portions of the arches with implant-supported prostheses.     

A radio-isotope study of the healing of mandibular bone grafts in patients

Radionucleotide scanning is now accepted as a reliable method of visualising the metabolic activity of the skeletal system. Its application to the maxillo-facial region is reviewed, and its possible role in monitoring the healing of bone grafts is discussed. The radio-isotope 99m technetium-methylene diphosphonate was used to study the revascularisation and healing of large autogenous bone grafts to the mandible in eight patients. The scans demonstrated the dynamic activity in the grafts and showed varying patterns in different types of grafts.     

Autogenous mandibular bone grafts and osseointegrated implants for reconstruction of the severely atrophied maxilla: a preliminary report

The purpose of this study is to present results obtained with a new procedure for reconstruction of the severely atrophied maxillary alveolar ridge that involves the use of intramembranous corticocancellous bone grafts obtained from the mandibular symphysis fixed to the residual bone by endosseous implants. A total of 107 implants were installed in grafted regions in 26 patients. The follow-up period ranged from 6 to 32 months, with a mean of 16 months. In partially edentulous patients the bone grafts were fixed with implants to the residual bone as 1) onlay graft to the alveolar ridge (8 implants in 4 patients); 2) grafts to the nasal and/or sinus floor after a transoral exposure and elevation of the mucosa of the maxillary sinus and/or the nasal mucosa (33 implants in 11 patients); or 3) a combination of these two (5 implants in 2 patients). In totally edentulous patients, implants and grafts were used as a combination of grafting to both the alveolar ridge and nasal and/or sinus floor sites (61 implants in 9 patients). One hundred of 107 implants showed normal clinical and radiologic healing, whereas 7 implants in 4 patients (6.5%) were lost prior to loading. Seventeen patients have had the implants and bone grafts loaded by a prosthodontic reconstruction from 6 to 26 months (mean, 14 months) without loss of any implants. Postoperative marginal resorption of the onlay bone graft of less than 15% was observed. These findings suggest, that the previously observed rapid resorption of endochondral iliac crest onlay bone grafts and the number of lost implants can be significantly reduced if bone from the mandibular symphysis firmly anchored with titanium implants is used.     

Alternative bone expansion technique for immediate placement of implants in the edentulous posterior mandibular ridge: a clinical report

PURPOSE: The aim of this study was to evaluate the effectiveness of a split-crest bone augmentation technique performed for immediate implant placement in thin edentulous posterior mandibular ridges. MATERIALS AND METHODS: In the present study, 125 implants were placed in posterior mandibular ridges of 30 patients. The mandibular buccal walls were split, expanded, and grafted with a combination of platelet-rich plasma and Cerasorb. The split segments were held in place by cortical bone screws. Before loading, periodontal status was checked, implant stability was evaluated with the Periotest, and panoramic radiographs and computerized tomography scans were obtained. Second-stage surgery (cover screw removal and healing abutment placement) was performed after 3 to 4 months. RESULTS: All implants osseointegrated successfully and underwent loading after 4 months. Optimal healing occurred 3 to 4 months earlier than the usual 6 to 9 months required, and no lip paresthesia was noted. DISCUSSION: Although onlay-inlay grafts, sandwich osteotomies, guided bone regeneration, piezoelectricity, and alveolar distraction have been indicated for augmentation in the posterior mandibular region, each of these techniques involves risks and complications. The crest-splitting bone expansion technique enables single-stage immediate implant placement and lateral ridge augmentation in thin crests and may prevent neurosensorial deficiencies. CONCLUSIONS: The split-crest surgical technique is a valid reconstructive procedure for sharp posterior mandibular ridges. If performed using platelet-rich plasma and Cerasorb, it can shorten the osseointegration period.     

Use of a piezoelectric surgical device to harvest bone grafts from the mandibular ramus: report of 40 cases

Forty patients (12 men, 28 women; mean age 44.9 +/- 13.95 years) with inadequate bone volume for implant placement in either the maxilla or the mandible were scheduled for bone-grafting procedures. Bone grafts were harvested with a piezoelectric surgical device (Piezosurgery, Mectron) from 45 donor sites and grafted into recipient sites prior to implant placement. After healing of the grafted sites, 109 implants were placed. Clinical evaluations were performed to assess the size and quality of the obtained grafts, complications at the donor and recipient sites, integration of the grafts, bone quality, resorption of the grafts, and ability to properly place implants. Piezosurgery allowed precise, clean, and smooth cutting with excellent visibility. Mean graft size was 1.15 cm3 (SD 0.5), with a maximum of 2.4 cm3. The quality of the obtained grafts was mainly cortical (71%), 42 of the 45 donor sites healed uneventfully (93.33%), and 50 of the 52 grafted sites healed uneventfully (96.15%).     

Cinegammography and 3-D emission tomoscintigraphy for evaluation of revascularized mandibular bone grafts: a preliminary report.

The following reports a study conducted to investigate a scintigraphic monitoring procedure for bone free flap in mandibular reconstruction. This procedure is based on the one hand, on vascular and bone cinegammography, and on the other hand, on vascular and bone 3-D tomoscintigraphy. We used a prospective cohort study design. All patients who underwent free flap mandibular reconstruction from April 1993 to April 1998 in the Salpêtrière University Hospital, France (20 cases) have been evaluated in relation to this scintigraphic procedure. Vascular and bone scintigraphy were performed within the second week after surgery during 2 consecutive days. All images were read by one author (J.- Y. B.), who did not know the skin status of the flap. The results were compared with the viability of revascularized bone grafts as evaluated by the skin status and Greenberg classification based on bone radiographs three months after reconstruction. Vascular cinegammography seems to be closely related to anastomosis patency. Bone cinegammography gives appreciable information on bone viability. 3-D vascular tomoscintigraphy remains difficult to interpret. 3-D bone tomoscintigraphy gives precise information on the viability of the different segments of the bone flap. These results suggest that vascular and bone 3-D tomoscintigraphy coupled with cinegammography have an excellent prognostic value. In the event of partial failure it can give information on the location of the impaired patency and on the osseous fragment which has lost any viability.     

Use of the mandibular staple bone plate with augmentation bone grafts

The mandibular staple bone plate is a helpful adjunct to the treatment of advanced mandibular atrophy when augmentation bone grafts are required. The vestibuloplasty procedure can often be eliminated or modified. The patient can be prosthetically rehabilitated sooner and experiences much greater stability than with the conventional denture. If instability contributes to bone loss, then the mandibular staple bone plate should decrease the rate of bone loss in these more vulnerable denture patients and subsequently improve the long term results of the augmentation procedures.     

Chin augmentation with a bone graft from the mandibular region

The prominent, square angles of the mandible are not generally considered an alluring virtue in Asian women because a square chin is thought to be masculine, and sunken cheeks are thought to be ill-fated. An oval, slender face is customarily preferred. A 28-year-old single woman requested reduction of the mandibular angle and concomitant chin augmentation. Each scalene triangular piece of the bone from both mandibular angles was carved and shaped like an obtuse triangle. One side of its surface was serrated to effect a curve, and the revision was fixed with a miniplate. The pieces were placed on top of each other, set on the symphysis menti, and were immobilized with screws. The excised fragments of the mandible were used as bone grafts to augment the chin during the same operation.     

Marginal bone loss of tissue- or bone-level implants after simultaneous guided bone regeneration in the posterior mandibular region: A retrospective cohort study

The cover image is based on the Original Article Marginal bone loss of tissue- or bone-level implants after simultaneous guided bone regeneration in the posterior mandibular region: A retrospective cohort study by Xiaoting Shen DDS et al., https://doi.org/10.1111/cid.13144 .

     

Use of bone grafts from the mandibular body in pre-implant surgery

Thirteen patients with resorption of the alveolar process in the upper or lower jaw were treated with augmentation using autogenous bone from the mandibular body. The objective and subjective results were retrospectively assessed. The morbidity of the donorsite was considered mild. 3 Patients experienced temporary sensory disturbance of the inferior alveolar nerve. In 1 patient spontaneous sequestration of a part of the transplant occured. In all patients the bonevolume at time of implantation was sufficient to insert the planned amount of implants. In total 46 implants were inserted. One implant was lost during follow-up and replaced. From this study it is concluded that the mandibular body can be considered as a good donor site for autogenous bone for pre-implant reconstruction of the alveolar process.     

Postinsertion pain in region of mandibular dental implants: a case report

This report describes the role of severe pain in failure of dental implants. A 27-year-old woman presented to the clinic to replace the missing mandibular right first molar and second premolar. A panoramic radiograph was taken, and a clinical examination was done. A decision was made to extract the mandibular right second molar, which had failing endodontics, and two dental implants were placed. Two days later, the patient reported severe pain in that area. Microscopic examination of the surgical specimen revealed longitudinal section of peripheral nerve in the implant site.     

Transmigration of mandibular canines: a report of six cases and a review of the literature

BACKGROUND: The transmigration of a mandibular canine is a rare phenomenon, the etiology of which is not clear. The literature on this rare condition is reviewed, and six cases of transmigrated mandibular canines are presented. REPORT: Panoramic radiographic examination of six patients revealed each patient had one impacted transmigrated mandibular canine. Of the six impacted teeth, the left mandibular canine was involved in four instances and the right in two. In one case the transmigrated canine was associated with a dentigerous cyst. SUMMARY: Transmigration of the mandibular canine is a rare event, and early radiographic examination of the patient is important for treatment. In addition, future studies may lead to a better understanding of this rare anomaly and improvement of the classification criteria.