Bone resorption around fixtures in edentulous patients treated with mandibular fixed tissue-integrated prostheses

Bone loss around osseointegrated titanium fixtures supporting mandibular fixed prostheses has been measured by means of stereoscopic intraoral radiography. Forty-six patients treated with the osseointegration implant method according to Br?nemark have been followed for an observation period of up to 6 years. The bone loss was small, approximately 0.5 mm during the first postsurgical year and thereafter 0.06 to 0.08 mm annually. Poor oral hygiene and clenching of teeth significantly influenced bone loss. More bone was lost around the medial fixtures than around the more posterior ones.     

Longitudinal electromyographic study of chewing patterns in complete-denture wearers.

A longitudinal electromyographic study of the anterior temporal and masseter activity during habitual chewing of apple was performed on 21 subjects provided with immediate complete dentures. At the pretreatment stage, when the patients having an anterior residual dentition were chewing, the peak mean voltages showed low values (range, 48 to 58 microV). After denture placement, there was a further decrease of the temporal activity that persisted to the 6-month stage. After the dentures were relined, a significant increase in chewing force of the temporal muscles was noted at the 1-year stage. During the second year, when no corrections of the dentures were made, the temporal activity decreased below the pretreatment level. The masseter muscle chewing activity generally showed no significant changes during the 2-year observation period. The mean durations of the chewing strokes and chewing cycles were longer than values reported in dentate samples and generally displayed no significant changes during the 2-year period.     

Dental professional's role in monitoring and maintenance of tissue-integrated prostheses

The long-term success of an implant-supported prosthesis is dependent not only on osseointegration of the implant to the surrounding osseous structures, but also the integrity and health of the surrounding peri-implant tissues. This paper defines and discusses the dental professional's role in (1) examining and assessing the peri-implant tissues (2) providing clinical maintenance protocols, and (3) recommending effective home-care instructions for a patient with implant-supported prostheses.     

自然牙与种植联合修复体基牙的骨吸收临床观察

目的 探讨自然牙与种植体联合固位修复中自然牙根与种植体周围骨吸收情况.方法 选取10例自然牙与种植体联合修复患者作为研究组,分别选择15例单种植体修复和15例单冠修复固定义齿作为对照组.种植体均于术后3个月行冠部修复体修复.分别于术后第1、6、12、18个月进行X线检查,对所有自然牙及种植体的周围骨吸收情况进行测量.结果 在18个月时自然牙与种植牙联合固位修复中组,自然牙根远中骨高度变化大于单冠组自然牙根(P＜0.05),其余各组均无统计学差异.联合修复的固位体及对照单颗天然牙和单颗种植体修复体均未出现修复体松动、折断.结论 自然牙与种植牙联合固位修复在短期内自然牙及种植体的周围骨吸收较少,可以达到临床应用要求.     

The effect of different prosthetic restorations on the dietary selection in edentulous patients. A longitudinal study of patients initially treated with optimal complete dentures and finally with tissue-integrated prostheses

The effect of prosthetic restoration of masticatory ability on dietary selection was evaluated in 23 edentulous patients with denture adaptation problems. The patients were first given optimal complete dentures and then a fixed prosthesis on tissue-integrated implants in the lower jaw. Changes in dietary selection were evaluated from 4-day records obtained before prosthetic treatment and on six occasions up to 78 months after treatment. With the method used, no significant changes in food selection were recorded during the rehabilitation period, except for a slight increase in intake of crisp bread and fresh fruit after treatment with fixed tissue-integrated prostheses in the mandibular jaw. It is concluded that an improved oral function will not in itself lead to a change in dietary selection and that dietary changes probably require professional and individually given dietary advice by a trained dietitian.     

Mandibular atrophy and metabolic bone loss. Mandibular ridge augmentation by combined sandwich-visor osteotomy and resorption related to metabolic bone state

22 edentulous women, 11 with and 11 without signs of metabolic bone loss were treated by a combined sandwich-visor osteotomy. Longitudinal studies showed a higher rate of resorption in women with radiographic signs of metabolic bone loss. The analysis was based upon lateral cephalometry.     

Apical root resorption in patients treated with comprehensive orthodontics

External apical root resorption (EARR) is a common--but seldom extreme--consequence of orthodontic treatment. Incisors are most at risk, perhaps because of their single roots and because they typically are moved farther than other teeth. We followed a cohort of patients (n = 153) treated with comprehensive orthodontics. EARR was scored on the upper incisors with a qualitative five-grade ordinal scale. There was no EARR at the start of treatment, but most (> 80%) exhibited slight-to-moderate EARR by the end of treatment (i.e., a loss of 1-2 mm). Cases treated with premolar extractions experienced more EARR because their incisors were retracted farther; however, the sum of the effects of patients' sex and age, and severity of the malocclusion, and the kind of mechanics used accounts for little of the overall variation in EARR. Instead, it appears that genetically-based inter-individual variation in susceptibility to EARR is the most influential factor. Research should be directed at understanding the biochemical nature of susceptibility so prospective patients can be screened to identify those at particular risk.     

Decreased alveolar bone resorption in rice rats treated with chlorhexidine and stannous fluoride

Rice rats were used to test the effect of topically applied chlorhexidine gluconate and stannous fluoride on the loss of periodontal bone. Eighty-eight weanlings were divided into eight groups of eleven animals each. Four groups were swabbed five times each week with either: a) 0.2 % chlorhexidine; b) 2 % chlorhexidine; c) 0.2 % chlorhexidine and 10 % stannous fluoride combined, or d) deionized water. Four other groups were swabbed only twice (once at the start and once at day 30) with either: e) 0.2 % chlorhexidine; f) 10 % SnF₂; g) 0.2 % chlorhexidine and 10 % SnF₂, or h) deionized water. After two months the animals were killed and the mandibular quadrants scored to estimate bone loss. Concentrations of 0.2 and 2 % chlorhexidine applied five times per week and 10 % SnF₂ applied only twice, significantly reduced bone loss when compared to the deionized water control. The more frequent applications had a significant beneficial effect as compared to the less frequent applications.     

Mandibular ridge augmentation and resorption with various visor procedures

Modifications of the visor osteotomy for ridge augmentation are presented. Cases treated by these methods were studied for bone augmentation and resorption by measurements made on lateral cephalometric headplates, and compared with other procedures using interpositional or rib onlay techniques. It was found that the modified visor procedures fulfilled the criteria for the ideal ridge augmentation technique better than the other methods. Their main advantage is that they use the bone available from the mandible itself, with only a secondary role for the bone graft material in most instances.     

Mandibular bone mineral density changes in complete and removable partial denture wearers: a 6-month follow-up study

PURPOSE: The purpose of the study was to determine the changes in bone mineral density of the mandible in complete and removable free-end saddle denture wearers over a 6-month period. MATERIALS AND METHODS: Twenty removable partial denture patients and 20 complete denture wearers participated. Two dental panoramic radiographs were taken from each patient, the first prior to denture delivery and the second after 6 months of denture wearing. Bone mineral density measurements were performed on panoramic radiographs with a five-step copper stepwedge attached to each film cassette. Bone mineral density values of the measured regions of interest were expressed in equivalents of the stepwedge thickness (mm). RESULTS: The results revealed minor changes in bone mineral density values of the examined regions in the 6-month period. Under the distal end of complete denture saddles, the bone mineral density values decreased, whereas the values under the distal end of removable partial dentures increased. However, the difference between the first and second measurements was not significant. In each of the examined groups, the bone mineral density values at the gonion increased significantly by approximately 20%. This was attributed to the increased strain forces of the masseter muscle at the gonion after denture delivery. CONCLUSION: Significant increase of bone mineral density values was registered 2 mm above the gonion in both complete and removable partial denture wearers. Age and gender were not related to the bone mineral density changes over a 6-month period.     

Mandibular alveolar bone volume in patients with different vertical facial dimensions

Objective

To evaluate if there is any difference in alveolar bone surface area in patients with high vertical facial dimension (long face), average vertical facial dimension (average face), and low vertical facial dimension (square short face).

Mandibular stability and condylar changes following orthognathic surgery in mandibular hypoplasia patients associated with preoperative condylar resorption

Clinical Oral Investigations - To evaluate postoperative mandibular stability and condylar changes in patients with mandibular hypoplasia and preoperative condylar resorption (CR) undergoing...     

Mandibular atrophy and metabolic bone loss. Mandibular ridge augmentation by combined sandwich-visor osteotomy and resorption related to metabolic bone state. A 5-year follow-up

92 patients, 31 with and 61 without signs of metabolic bone loss, were treated with a combined sandwich-visor osteotomy. A 5-year follow-up showed a significantly higher rate of resorption in patients with radiographic signs of metabolic bone loss. The analysis was based upon lateral cephalometry.     

Pattern of bone resorption in vertically fractured, endodontically treated teeth

PURPOSE: To evaluate the clinical pattern of alveolar bone resorption associated with vertically fractured, endodontically treated teeth in correlation to clinical symptoms.Material and Methods: The pattern of bone resorption was evaluated in 66 maxillary premolars, 13 mandibular premolars, and 31 mesial roots of mandibular molars extracted during an 18-month period because of vertical root fractures. Type and duration of symptoms were recorded and correlated to the pattern of bone resorption. RESULTS: A V-shaped pattern osseous defect (dehiscence) was typical (91%) to the buccal plate rather than a U-shaped shallow, rounded, slow grade resorption in the palatal or lingual plate. Fenestration of the buccal plate was observed in 10 patients (9%). A positive correlation between type of symptoms and amount of buccal bone resorption was found (P <.0001). The resorptive defect was always facing the fracture line. CONCLUSIONS: A typical pattern of bone resorption in vertical root fracture cases as shown in this study can be helpful to the clinician in diagnosing vertical root fracture when an exploratory full flap surgical procedure is performed.     

Mandibular resorption from silicone chin implants in children

Silicone implants were placed in the nasal, cheek, and chin areas in children with Down's syndrome to improve facial appearance. Clinical and radiologic follow-up evaluation revealed significant crater-like bone resorption in the mandibular symphysis in 75% of the cases. All of these implants were removed, and the bone showed regrowth to the presurgical state. No sign of bone damage was present in the malar or nasal areas.