Diabetes mellitus may increase bone loss after occlusal trauma and experimental periodontitis

Background: Diabetes mellitus (DM) involves metabolic changes that can negatively influence periodontal tissues, resulting in more prevalent and severe periodontitis and impaired bone formation. Occlusal trauma (OT) is an injury of the supportive periodontium that results in bone loss. It can be hypothesized that DM would increase bone loss after OT, mainly when associated with periodontitis. Thus, the aim of the present study is to evaluate the influence of DM on bone response in the furcation area of teeth subjected to OT in the presence, or absence, of experimental periodontitis (EP) in the rat model. Methods: Thirty-two male Wistar rats were assigned to four groups: 1) group 1 (G1): DM+OT+EP (n = 8); 2) group 2 (G2): DM+OT (n = 8); 3) group 3 (G3): OT+EP (n = 8); and 4) group 4 (G4): OT (n = 8). G1 and G2 received a single intraperitoneal injection of streptozotocin (STZ). After 10 days, G1 and G3 were subjected to EP by ligature placement. Fifteen days after the start of EP, OT was induced by the creation of a premature contact. The animals were euthanized 35 days after DM induction. Results: DM enhanced bone loss in the presence of OT combined with EP, but did not increase bone loss in teeth subjected to OT alone. EP caused greater bone loss when associated with OT. Conclusion: Within the limits of this animal study, it can be concluded that DM enhances bone loss in the presence of occlusal trauma associated with EP.     

Peri-implant bone loss caused by occlusal overload: repair of the peri-implant defect following correction of the traumatic occlusion. A case report

The purpose of this case report is to demonstrate the relation between occlusal overload and peri-implant bone loss and the reversal of the situation after removal of the offending forces. The placement of an unstable removable prosthesis on 3 well-integrated implants that had been stable for 9 years caused noticeable bone loss after 6 months. The elimination of the traumatic occlusion reversed the situation, and a remarkable healing of the peri-implant tissue occurred until the pretrauma condition was nearly restored. The condition has been stable for the past 4 years.     

Gelatinase B is associated with peri-implant bone loss

The aim of this study was to clear whether gelatinase B is associated with peri-implant bone loss (PBL). Peri-implant sulcus fluid was collected from 46 implant sites in 12 patients. These sites were also characterized using modified Gingival Index (mGI). Activated and total gelatinase B levels, measured using a modified urokinase assay, showed correlation with PBL (n = 46, Spearman's rank correlation test). Activated and total gelatinase B values were significantly higher in PBL > 3 mm group (n = 6) compared to PBL < 1 mm (n = 29) and 1 < PBL < 3 mm (n = 11) groups (rank sum test). Activated gelatinase B level in mGI > 0.5 group (n = 24) was clearly higher compared to mGI = 0 (n = 13) and < or = 0.5 (n = 9) groups (Rank sum test). We conclude that gelatinase B is associated with PBL. Activation of gelatinase B together with elevated mGI eventually reflect active phases of peri-implantitis and may prove to be diagnostically useful.     

Evaluation of peri-implant bone loss around platform-switched implants

This clinical and radiographic prospective study evaluated bone loss around two-piece implants that were restored according to the platform-switching protocol. One hundred thirty-one implants were consecutively placed in 45 patients following a nonsubmerged surgical protocol. On 75 implants, a healing abutment 1 mm narrower than the implant platform was placed at the time of surgery. On the remaining implants, a healing abutment of the same diameter as the implant was inserted. All implants were positioned at the crestal level. Clinical and radiographic examinations were performed prior to surgery, at the end of surgery, 8 weeks after implant placement, at the time of provisional prosthesis insertion, at the time of definitive prosthesis insertion, and 12 months after loading. The data collected showed that vertical bone loss for the test cases varied between 0.6 mm and 1.2 mm (mean: 0.95 +/- 0.32 mm), while for the control cases, bone loss was between 1.3 mm and 2.1 mm (mean: 1.67 +/- 0.37 mm). These data confirm the important role of the microgap between the implant and abutment in the remodeling of the peri-implant crestal bone. Platform switching seems to reduce peri-implant crestal bone resorption and increase the long-term predictability of implant therapy.     

Management of peri-implant bone loss using guided bone regeneration: a clinical report

This clinical report presents a patient who developed peri-implant bone loss around 2 maxillary endosseous root-form implants after restoration with cement-retained single crowns. Significant localized bone loss occurred around 1 of the implants due to retained excess cement. Reparative treatment consisted of a guided bone regeneration technique. Following a 9-month period of submerged healing, the implants were re-exposed and restored to complete function.     

Titanium particles: An emerging risk factor for peri-implant bone loss

ObjectiveTo investigate the presence of titanium particles in peri-implant tissues in cases diagnosed with peri-implantitis, and to identify immunological reactions that these particles may elicit.MethodsTen peri-implant tissue biopsies of patients diagnosed clinically and radiographically with peri-implantitis were obtained from the archives of Oral Pathology Centre, University of Otago. The inclusion criteria involves: bleeding on probing, ≥6 mm probing depth and ≥3 mm radiographic bone loss around the dental implant. Peri-implant tissue samples were evaluated using scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDS) to identify of sites with/without titanium particles. Antibodies against human transforming growth factor beta 1 (TGF-β1), receptor activator of nuclear factor kappa-B ligand (RANKL), interleukin 33 (IL-33) and cluster of differentiation 68 (CD68) were used to stain the specimens. ImageJ software was used to standardise the sampling area, compare and characterise the inflammatory infiltrate in tissues with/without titanium particles. Inflammatory cytokines positivity was assessed using the immunoreactive scores (IRSs).ResultsLight microscopy and SEM-EDS analysis identified titanium wear particles in 90% of the tissue samples, associated with a mixed chronic inflammatory infiltrate. Quantification analysis of RANKL revealed significantly higher IRS and intensity scores (p < 0.05) in areas containing titanium. High intensity, proportion and IRSs of TGF-β1 and IL-33 were observed in areas with titanium. CD68 had higher IRSs in the absence of titanium particles.ConclusionsSignificant overexpression of the cytokine RANKL was observed, with a trend for over-expression of IL-33 and TGF-B1 in areas with titanium. Further studies with large sample size and appropriate control group for quantification analysis is needed to confirm the role of titanium particles in initiating bone loss.     

Collagenases in different categories of peri-implant vertical bone loss

The loosening of dental implants is associated with peri-implant vertical bone loss. The mechanisms and mediators of this bone destruction are not known. To test the hypothesis that collagenase-2 and collagenase-3 might be markers or maybe even mediators in this process, we measured collagenase-2 (time-resolved immunofluorometric assay) and collagenase-3 (quantitative immunoblot) in peri-implant sulcus fluid in 49 implant sites in 13 patients. Vertical bone loss was graded as being < 1 mm, from 1 to 3 mm, or > 3 mm. The severity of inflammation, as rated according to Gingival Index, did not correlate with the category of bone loss (p > 0.05). Collagenase-2 and collagenase-3 were higher (p < 0.05) in the group which had lost > 3 mm of bone than in the two other groups. Gingival Index is not a clinically important marker for bone loss, but collagenase-2 and collagenase-3 in peri-implant sulcus fluid are. They might participate in peri-implant osteolysis.     

Systemic risk factors for peri-implant bone loss: a systematic review and meta-analysis

The aim of this study was to determine the influence of patient-related systemic risk factors (systemic disease, genetic traits, chronic drug or alcohol consumption, and smoking status) on peri-implant bone loss at least 1 year after implant installation and prosthetic loading. An electronic search was performed of MEDLINE, EMBASE, and The Cochrane Central Register of Controlled Trials up to January 2012. One thousand seven hundred and sixty-three studies were identified. After applying a three-stage screening process, 17 articles were included in the qualitative analysis, but only 13 in the quantitative analysis, since smoking was a common exposure. The meta-analysis of these 13 studies (478 smokers and 1207 non-smokers) revealed a high level of heterogeneity and that smoking increases the annual rate of bone loss by 0.164 mm/year. Exposure to smoking had a harmful effect on peri-implant bone loss. However, the level of evidence for oral implant therapy in patients with systemic conditions is very low. Future studies should be improved in order to provide more robust data for clinical application.     

Mandibular fracture caused by peri-implant bone loss: report of a case

BACKGROUND: A major complication related to excessive bone loss around implants is fracture of the mandible. This complication is most likely to occur in a very atrophic mandible. A 57-year-old woman presented with progressive pain and swelling that had been present for 5 days in the right frontal region of the mandible. An intraoral radiograph revealed a radiolucency around one of the implants in the interforaminal region. METHODS: Ten years earlier, 4 hollow-screw implants of 10 mm length had been inserted in the interforaminal region of the edentulous mandible. Throughout the 10-year postoperative period, no adverse clinical events were seen; however, during the last 7 years, no radiographic follow-up was performed. Mobility was tested after removal of the bar, on which one of the implants appeared to be mobile. The mobile implant was removed together with the fibrous tissue. RESULTS: At a recall visit 2 weeks later, a radiograph revealed a fracture of the mandible at the explantation site. Characteristic features of the hollow-screw implant are the hollow body and the transverse openings in the side walls of the implant. It has been reported that these characteristic features can enhance infection and rapid bone loss, but a case of mandibular fracture has never been described. CONCLUSION: Radiographs should be taken on a regular and perhaps more frequent basis to diagnose excessive bone loss, so that measures can be taken to prevent the risk of mandibular fracture.     

Association between loss of occlusal support and symptoms of functional disturbances of the masticatory system

The purpose of this study was to evaluate the association of loss of occlusal support with symptoms of functional disturbances of the masticatory system, in particular with the ones related to the temporomandibular dysfunction. A total of 483 adult subjects randomly selected from the population living in the municipality of Segrate, northern Italy, were studied. Subjects were interviewed by questionnaire about oral conditions and occurrence of symptoms of disturbances of the masticatory system. Also, denture was examined by dentists during the interview. Loss of occlusal support was observed in 60.2% of the subjects, symptoms of functional disturbances in 68.7% and temporomandibular dysfunction in 55.1%. At univariate analysis loss of occlusal support was mainly associated with a feeling of stiffness or fatigue of the jaws (P < 0.001), difficulty in closing the mouth (P < 0.005) and difficulty on mastication (P < 0.0001). Association with temporomandibular dysfunction as a whole was significant also (P < 0.001). Multiple age- and sex-adjusted logistic analysis disclosed a significant strong impact of loss of occlusal support on difficulty with mastication (odds ratio = 7.0, P < 0.0001). At that analysis, no significant relationship resulted with symptoms of temporomandibular dysfunction. These findings confirm that presence of an adequate occlusal support is a relevant factor in maintaining an efficient chewing, and also suggest that it may play any indirect role in preventing occurrence of symptoms of temporomandibular dysfunction.     

Stress and inflammation as a detrimental combination for peri-implant bone loss

The causes of peri-implant bone loss continue to be controversial. To determine the impact of biomechanical stress and inflammation, we investigated a total of 80 interforaminal implants in situ for more than 10 years. Two stress groups, with 14 patients each, were established: a low-stress situation with single-standing implants, and an increased-stress situation with splinted implants. To categorize inflammation, we introduced a Composite Inflammation Score using 4 inflammatory parameters. Peri-implant bone loss was calculated from digital panoramic radiographs. To differentiate between the effects of stress and inflammation, we compared bone loss in both stress groups at equivalent levels of inflammation. With greater Composite Inflammation Score values, a clear discrepancy between single-standing and splinted implants was evident (p = 0.117/0.000, regression analysis; p = 0.135/0.000, analysis of variance; p = 0.002, t tests). While stress and inflammation alone may not necessarily be detrimental factors, the presence of stress heightens peri-implant bone loss significantly as inflammation increases.     

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...     

Histological evaluation of peri-implant bone at implants subjected to occlusal overload or plaque accumulation

Breakdown of bone around oral implants following occlusal overload or plaque accumulation was evaluated in monkeys. 5 screw-type implants of pure titanium (Astra Tech) were inserted in the mandible of 4 monkeys (Macaca Fascicularis). 6 months after insertion of the implants a fixed partial prosthesis was mounted on the 2 implants in 1 of the lateral segments. The prosthesis was in supra-occlusal contact with an antagonizing splint and caused a lateral directed excessive occlusal load (overload). Implants retaining the prosthesis were brushed 1 × week and subgingival cleaning was performed 1 × month. The remaining implants were never cleaned and, additionally, a cotton cord was placed around the abutments of these implants to promote plaque accumulation. 6 out of 8 implants with occlusal overload became loose. 2 of these were lost, whereas the remaining 4 were retained in the jaws. After 18 months of occlusal load or plaque accumulation, the monkeys were sacrificed. Tissue blocks with the implants were infiltrated and embedded in acrylic resin. Approximately 50 pm thick sections of the implants and surrounding tissues were made. All implants with plaque accumulation were osseointegrated, but exhibited an average histologic marginal bone loss of 2.4 mm (range: 0.8-4.0 mm). Of the 6 implants with occlusal overload available for histologic analysis, 2 implants in 1 monkey had lost osseointegration completely and 2 other implants were osseointegrated in the apical part only, whereas the remaining 2 were still osseointegrated but exhibited a bone loss of 1.8-1.9 mm.