Prevention of bone loss for edentulous patients

This paper examines the consequences of being edentulous particularly on the intra-oral hard tissues. Short, medium and long-term studies of the overall post-extraction changes are reviewed and the bone loss that might be anticipated quantified. Following on from this, means by which bone loss may be prevented are reviewed. The bone-preserving potential of conventional and implant-retained overdentures is presented, advantages and potential problem areas highlighted.     

Factors influencing the preservation of the periimplant marginal bone

Esthetic outcomes cannot be attributed to a single parameter. Rather, as this article shows, they are the result of a number of important factors, especially in the esthetic zone. An understanding of the meaning of biologic width, of the integration of the platform-switching concept into implant treatment facilitates the preservation of a stable marginal bone level around the implant neck. This stable bone then serves to support the soft tissue, determining the long-term esthetic and functional treatment outcomes stability.The following points should be noted: (1) A prefabricated post that can be used both as a temporary post and as the definitive abutment helps to avoid a frequent replacement of secondary components, provided that the 3-dimensional position of the implant is correct. It prevents a repeated destruction of the connective-tissue attachment on the biologic width, which would carry with it the risk of bone resorption. (2) A special implant and abutment design (a ledge and integration of the biologic width/tapered shape of the post) facilitates nonsurgical lengthening and thickening of the periimplant soft tissue. This leads to the establishment of a wider and more resistant zone of connective tissue. (3) A microrough and nanorough titanium surface extending to the implant shoulder in conjunction with the platform-switching concept provides osseous integration along the entire length of the implant. A fine thread optimally distributes the masticatory forces in the region of the implant neck, avoiding further bone loss in this region.     

Intrusion of incisors in adult patients with marginal bone loss

Elongated and spaced incisors are common problems in patients suffering from severe periodontal disease. Thirty patients characterized by marginal bone loss and deep overbite were treated by intrusion of incisors. Three different methods for intrusion were applied: (1) J hooks and extraoral high-pull headgear, (2) utility arches, (3) intrusion bent into a loop in a 0.17 x 0.25-inch wire, and (4) base arch as described by Burstone. The intrusion was evaluated from the displacement of the apex, incision, and the center of resistance of the most prominent or elongated central incisor. Change in the marginal bone level and the amount of root resorption were evaluated on standardized intraoral radiographs. The pockets were assessed by standardized probing and the clinical crown length was measured on study casts. The results showed that the true intrusion of the center of resistance varied from 0 to 3.5 mm and was most pronounced when intrusion was performed with a base arch. The clinical crown length was generally reduced by 0.5 to 1.0 mm. The marginal bone level approached the cementoenamel junction in all but six cases. All cases demonstrated root resorption varying from 1 to 3 mm. The total amount of alveolar support--that is, the calculated area of the alveolar wall--was unaltered or increased in 19 of the 30 cases. The dependency of the results on the oral hygiene, the force distribution, and the perioral function was evaluated in relation to the individual cases. It was obvious that intrusion was best performed when (1) forces were low (5 to 15 gm per tooth) with the line of action of the force passing through or close to the center of resistance, (2) the gingiva status was healthy, and (3) no interference with perioral function was present.     

Prevalence of periimplant disease in partially edentulous patients: a practice-based cross-sectional study

Objectives: Evaluation of the prevalence rates of periimplant mucositis and periimplantitis in partially edentulous patients in a private dental practice. Material and methods: The data of 89 patients were collected (52 female, 37 male, age at time of implant placement: 51.8±10.3 years). All patients had been treated with dental implants of the same type and fixed superstructures between January 1999 and June 2006 (observational period: 68.2±24.8 months). Results: The patient‐related prevalence rate of periimplant mucositis (probing depth ≥4 mm and bleeding on probing [BOP]) was over all 44.9%. The respective rates in non‐smokers without periodontal history were 30.4% and in smokers with periodontal history 80%. The multiple logistic regression analysis identified a significant association of mucositis with the independent variable “smoker” (odds ratio [OR] 3.77; P=0.023). The patient‐related prevalence rate of periimplantitis (probing depth ≥5 mm, BOP/pus, radiographic bone loss) was 11.2% (smokers with periodontal history: 53.3%, non‐smokers: 2.8%). No periimplant disease was diagnosed in non‐smoking patients without periodontal history and with a good compliance after treatment. Statistical analysis identified a significant association of periimplantitis with “smoker” (OR: 31.58; P<0.001) and “compliance” (OR: 0.09; P=0.011). Periodontal history in general showed no significant association with periimplantitis. Conclusions: Smoking and compliance are important risk factors for periimplant inflammations in partially edentulous patients. To cite this article:
Rinke S, Ohl S, Ziebolz D, Lange K, Eickholz P. Prevalence of periimplant disease in partially edentulous patients: a practice‐based cross‐sectional study.
Clin. Oral Impl. Res. 22 , 2011; 826–833
doi: 10.1111/j.1600‐0501.2010.02061.x     

Prevalence of marginal alveolar bone loss in children

Previous studies have indicated that the prevalence of marginal alveolar bone loss (MABL) in several populations, but not yet in the Mexican children. Therefore, the present study examined the prevalence of MABL in a group of Mexican children. The characteristics of the proximal surfaces and the status of the adjacent alveolar bone, were recorded at 1307 sites from 209 diagnostic bite-wing radiographs, from 115 children. MABL was found in the radiographs of 7.8% of the children or 1.5% of the sites. The present prevalence finding is relatively low when compared to previous studies on children attending dental clinics. MABL was found already in 4-year-old children, confirming previous studies, which indicate the possibility of early onset of periodontitis in children.     

Implant marginal bone loss in maxillary sinus grafts

PURPOSE: The marginal bone loss (MBL) around implants placed in maxillary sinus grafts was evaluated. MATERIALS AND METHODS: The study consisted of 70 patients who had undergone 81 sinus-graft procedures (total 212 screw-type implants). Complete radiographic records were available for 160 implants, which were used to calculate MBL (follow-up 6 to 56.5 months). Habits (smoking, bruxism), surgical phase parameters (preoperative residual bone, grafting material, implant characteristics, and complications), and prosthetic parameters (crown-implant ratio, marginal fit, and opposite-arch restoration) were recorded for each patient and statistically analyzed regarding MBL. RESULTS: Cumulative survival and overall radiographic success rates were 95.5% and 83.7% for 4.5 years, respectively. Smoking, small implant surface area, and a delayed implantation approach were related to enhanced MBL, with mean MBL values of 0.24 mm/y (P < .011), 0.21 mm/y (P < .031), and 0.31 mm/y (P = .052), respectively. In residual bone of < or =4 mm, the relation to enhanced MBL was stronger (P < .018) for delayed implantation. DISCUSSION: Survival and radiographic success rates compare well with other reports. However, most studies modify success criteria regarding MBL. Smoking may be a primary risk factor regarding implant success. Implants with greater surface area values could compensate for problematic bone characteristics (e.g., in grafted maxillary sinuses). The effect of delayed implantation on MBL was surprising and may prompt simultaneous implantation whenever primary stability can be achieved. CONCLUSIONS: Smoking and implant surface area affected MBL in this patient population. Criteria for long-term implant success should be revised to a standard.     

Impact of smoking on marginal bone loss

PURPOSE: To compare marginal implant bone loss (MBL), survival, and radiographic evidence of success of dental implants among smokers and nonsmokers. MATERIALS AND METHODS: Consecutive records of 161 patients (aged 23 to 89 years, mean 57 years) treated with a total of 646 implants between the years 1995 and 1998 were examined. Patients were divided into 3 groups: nonsmokers, moderate smokers, and heavy smokers. Tobacco exposure was calculated by cigarettes per day and by pack-years. Follow-up ranged from 1 to 7 years (mean 3.8 years). Postoperative panoramic radiographs obtained before implant exposure and annually thereafter were analyzed for MBL changes. The influence of smoking and other variables on MBL was analyzed at all implant sites. RESULTS: Generally, smokers had more MBL than nonsmokers (0.153 +/- 0.092 mm and 0.047 +/- 0.048 mm, respectively; P < .001). When each jaw was examined separately, smoking had a greater effect on MBL in the maxilla than in the mandible (0.158 +/- 0.171 mm versus 0.146 +/- 0.158 mm, respectively; P < .001). Furthermore, in the maxilla, heavy smokers had the greatest amount of MBL (0.1897 +/- 0.1825 mm), followed by moderate smokers (0.123 +/- 0.156 mm) and nonsmokers (0.0460 +/- 0.070 mm) (P < .001). In the mandible, there was no distinction between heavy and moderate smokers, and both had greater MBL than nonsmokers (P < .001). Only 3 of the 646 implants failed; the cumulative survival rate was 99.5%. Overall radiographic success rate was 93.2%. Nonsmokers had a higher radiographic success rate (97.1%) than smokers (87.8%) (P < .001). CONCLUSIONS: This study demonstrated a relationship between MBL and smoking habits. A higher incidence of MBL was found in the smoking group, and this was more pronounced in the maxilla.     

Mandibular atrophy and metabolic bone loss. A radiologic analysis of 126 edentulous patients

An analysis of 69 edentulous patients with severe atrophy of the mandible and submitted to ridge augmentation, together with 57 normal edentulous patients, revealed in about half of the patients with a severe atrophy radiological evidence of metabolic bone loss. In the group of normal edentulous patients, this was only found in post-menopausal women.     

Mineralized bone loss in partially edentulous trabeculae of ovariectomized rabbit mandibles

OBJECTIVE: The purpose of this study was to evaluate trabeculae changes in partially edentulous bone in ovariectomized rabbits. BACKGROUND: Numerous clinical studies have suggested that the greater risk for oral bone loss in females may be correlated with osteoporosis after menopause. Knowledge of trabecular changes in partially edentulous bone in animals with loss of ovarian function may be beneficial in the diagnosis and treatment of partially edentulous patients of postmenopausal women. METHODS: Twelve adult female Japanese white rabbits were examined. The mandibular incisors were initially extracted to simulate the partially edentulous bone. Six animals were bilaterally ovariectomized and the other six sham-ovariectomized 12 weeks after tooth extraction. The partially edentulous parts of distal mandibular bodies were processed undecalcified 12 weeks after ovariectomized or sham-ovariectomized surgeries and examined by quantitative trabecular bone histomorphometry. RESULTS: In ovariectomized rabbits, there were significant increases in trabecular separation, osteoid volume, osteoid thickness, osteoid width, eroded surface, and mineral apposition rate, and a significant decrease in trabecular number. CONCLUSION: The results of sparser trabecular structure, more trabecular osteoid, and increased trabecular bone turnover demonstrate mineralized bone loss in partially edentulous trabeculae of ovariectomized rabbit mandibles and suggest that the same loss may occur in postmenopausal women.     

Steroid-induced mandibular bone loss in relation to marginal periodontal changes

Long-term high-dose glucocorticosteroid treatment may be suspected as causing profound marginal periodontal bone loss due to the immunosuppressive/antiinflammatory effects and due to the osteoporotic side-effects. This study comprised an analysis of the loss of the mandibular and forearm bone mineral content (BMC), measured in vivo by dual-photon scanner, in relation to the concomitant changes of the periodontal indices (visible plaque, gingival bleeding, loss of attachment) in 17 acute nephrotic dentate patients undergoing intensive steroid treatment for 12 months. The measurements were performed at start of treatment, when all patients were considered healthy as regards the skeleton, and at the 6-month and 12-month follow-up. The mean BMC loss at the standard sites of the mandible and the forearm bones was 5.6%/year at both sites. No significant changes could be demonstrated in the periodontal indices (P greater than 0.10), and no relation was found between the mandibular BMC loss and the periodontal condition (R = 0.06, P greater than 0.10). In conclusion, profound marginal periodontal bone loss does not seem to be a prominent side-effect of long-term glucocorticosteroid treatment, although the degree of induced osteopenia in the mandible corresponds to that in other cortical bones of the skeleton.     

Long-term stability of osseointegrated implants in augmented bone: a 5-year prospective study in partially edentulous patients

This prospective clinical study evaluated the 5-year survival and success rates of 66 titanium implants placed in bone that had been previously augmented with autografts and nonresorbable barrier membranes. During the observation period, three patients with five implants dropped out of the study. None of the remaining 61 implants were lost during the follow-up period (implant survival rate of 100%). One implant exhibited a periimplant infection, whereas 60 implants were considered clinically successful at the 5-year examination, resulting in a 5-year success rate of 98.3%. It can be concluded that the clinical results of implants in regenerated bone are comparable to those of implants in nonregenerated bone.     

Long-term treatment costs associated with implant-supported mandibular prostheses in edentulous patients

PURPOSE: The study's aim was to report long-term costs in edentulous patients treated with mandibular implant-supported prostheses. MATERIALS AND METHODS: Ninety patients were divided into four groups based on the type of implant prosthesis (fixed or overdenture) and treatment year. Records were obtained from dental charts, and an economic analysis from the patient's perspective was conducted. Clinical time associated with various procedures was measured and applied to the four groups. Salary rates by age, occupation, and gender were used to value patients' time. Direct clinical and time costs over 10 years were converted to 2002 Canadian dollars using the Consumer Price Index and discounted at a 3% rate. A sensitivity analysis at an equal salary rate was carried out to test the robustness of the time costs. RESULTS: Initial treatment and maintenance costs over the observation period were significantly higher for fixed compared to overdenture prostheses. A significant improvement in maintenance costs for the first patient group treated with fixed prostheses was observed over the follow-up period. Longer term (15 years) treatment costs for the initial two groups were significantly higher for the fixed group. The sensitivity analysis at an equal salary rate demonstrated the same trend: Time costs were significantly higher for the fixed groups. CONCLUSION: Long-term treatment costs indicated that the mandibular overdenture was a less expensive treatment compared to the fixed implant prosthesis.     

牙周维护对种植体周围边缘骨稳定性的影响

目的:探讨牙周维护对种植体周围边缘骨稳定性的影响.方法:选择上颌后牙缺失者,实验组为重度骨缺损10例,通过上颌窦底提升,同期植入种植体,种植前进行口腔卫生训练,修复后认真进行口腔卫生维护,定期复查,洁治;对照组为无骨缺损10例,种植修复后前3个月以患者日常方式进行口腔卫生维护,之后同实验组.修复后3、6、12个月分别检...