Influence of alcohol and tobacco habits on peri-implant marginal bone loss: a prospective study

A prospective clinical study was conducted to explore the possible link between peri-implant bone loss and the widespread habits of tobacco smoking and alcohol consumption. One hundred and eighty-five patients who received 514 implants were followed up for 3 years. Peri-implant marginal bone loss was evaluated by digital panoramic radiography and image analysis techniques. Multivariate analysis showed that peri-implant marginal bone loss was significantly related to a daily consumption of >10 g of alcohol, tobacco use and increased plaque levels and gingival inflammation. The present results indicate that daily alcohol consumption and tobacco use may have a negative influence on predictable long-term implant treatment outcomes, producing peri-implant bone loss and compromising restorative treatment with implant-supported prostheses.     

Resonance frequency analysis and damping capacity assessment. Part 2: peri-implant bone loss follow-up. An in vitro study with the Periotest and Osstell instruments

OBJECTIVE: We compared the performance of damping capacity assessment (Periotest device) to resonance frequency analysis (Osstell device) in the assessment of peri-implant bone loss in an in vitro experiment. MATERIAL AND METHODS: Screw-type oral implants were polymerized into acrylic blocks. Peri-implant bone loss was simulated by successively removing defined portions of material surrounding the implants in millimeter increments. Measurement values of both devices were compared by assessing the associated measurement errors, by calculating correlation analyses and drawing scatterplots, and by means of regression analysis referring to increasing bone loss. RESULTS: Both devices produced comparable results suggesting agreement of the measured implant stability values to the actual loss of peri-implant resin. There was a noticeable correlation of the Periotest and Osstell implant stability values. CONCLUSION: The results of this experiment suggest agreement in predicting the actual implant stability with both the instruments with the Osstell instrument being the more precise device.     

Extent of peri-implantitis-associated bone loss

Objective: The purpose of the present study was to describe the extent of peri-implantitis-associated bone loss with regard to implant position.
Material and methods: Patient files and intra-oral radiographs from 182 subjects were analysed. Among the 1070 examined implants, 419 exhibited peri-implantitis-associated bone loss. The position of each implant within the jaw and fixed reconstructions was determined. In the radiographs the distance between the abutment-fixture junction and the most coronal position of bone to implant contact was assessed at the 419 affected implants using a magnifying lens (× 7) with a 0.1 mm graded scale.
Results: About 40% of the implants in each subject was affected by peri-implantitis-associated bone loss. The proportion of such implants varied between 30% and 52% in different jaw positions and the most common position was the lower front region. In addition, affected implants were found in larger proportions among mid than end abutments irrespective of supporting fixed complete or fixed partial dentures.
Conclusion: It is suggested that peri-implantitis occurs in all jaw positions and that an end-abutment position in a fixed reconstruction is not associated with an enhanced risk for peri-implantitis.     

Influence of controlled immediate loading and implant design on peri-implant bone formation

AIM: Tissue formation at the implant interface is known to be sensitive to mechanical stimuli. The aim of the study was to compare the bone formation around immediately loaded versus unloaded implants in two different implant macro-designs. MATERIAL AND METHODS: A repeated sampling bone chamber with a central implant was installed in the tibia of 10 rabbits. Highly controlled loading experiments were designed for a cylindrical (CL) and screw-shaped (SL) implant, while the unloaded screw-shaped (SU) implant served as a control. An F-statistic model with alpha=5% determined statistical significance. RESULTS: A significantly higher bone area fraction was observed for SL compared with SU (p<0.0001). The mineralized bone fraction was the highest for SL and significantly different from SU (p<0.0001). The chance that osteoid- and bone-to-implant contact occurred was the highest for SL and significantly different from SU (p<0.0001), but not from CL. When bone-to-implant contact was observed, a loading (SL versus SU: p=0.0049) as well as an implant geometry effect (SL versus CL: p=0.01) was found, in favour of the SL condition. CONCLUSIONS: Well-controlled immediate implant loading accelerates tissue mineralization at the interface. Adequate bone stimulation via mechanical coupling may account for the larger bone response around the screw-type implant compared with the cylindrical implant.     

Impact of local predisposing/precipitating factors and systemic drivers on peri-implant diseases

Background

Strong evidence suggests the infectious nature of peri-implant diseases occurring in susceptible hosts. Epidemiological reports, though, indicate that peri-implantitis is a site-specific entity. Hence, the significance of local factors that may predispose/precipitate plaque accumulation and the impact of systemic drivers that alter the immune response are relevant in the prevention and management of peri-implant disorders.

Purpose

The purpose of the present review is to shed light on the significance of local and systemic factors on peri-implant diseases, making special emphasis on the associations with peri-implantitis.

Methods

The biologic plausibility and supporting evidence aiming at providing a concluding remark were explored in the recent scientific literature for local predisposing/precipitating factors and systemic drivers related to peri-implant diseases.

Results

Local predisposing factors such as soft tissue characteristics, implant position and prosthetic design proved being strongly associated with the occurrence of peri-implant diseases. Hard tissue characteristics, however, failed to demonstrate having a direct association with peri-implant diseases. Robust data points toward the strong link between residual sub-mucosal cement and peri-implant diseases, while limited data suggests the impact of residual sub-mucosal floss and peri-implantitis. Systemic drivers/habits such as hyperglycemia and smoking showed a strong negative impact on peri-implantitis. However, there is insufficient evidence to claim for any link between metabolic syndrome, atherosclerotic cardiovascular disease, and obesity and peri-implant diseases.

Conclusion

Local predisposing/precipitating factors and systemic drivers may increase the risk of peri-implant diseases. Therefore, comprehensive anamnesis of the patients, educational/motivational programs and exhaustive prosthetically-driven treatment planning must be fostered aiming at reducing the rate of biological complications in implant dentistry.     

Impact of supportive periodontal therapy and implant surface roughness on implant outcome in patients with a history of periodontitis

OBJECTIVE: This review searched for a relationship between susceptibility to periodontitis and peri-implantitis, with implant outcome as the primary outcome variable and supportive periodontal therapy (SPT) and implant surface roughness as confounding factors. MATERIAL AND METHODS: It is based on a MEDLINE search up to June 2006. Only 16 fulfilled the selection criteria. The heterogeneity of the studies (e.g. periodontal status, SPT, prosthetic design, ...) rendered a meta-analysis impossible. The impact of a history of periodontitis on early implant loss was negligible. Only five papers reported sub-data for patients with different degrees of periodontitis. Four out of five papers indicate a higher incidence of late implant loss and/or marginal bone loss in patients with a history of periodontitis. This difference was most obvious for very rough implants (three papers), and/or when SPT was not organized (one paper). Other confounding factors were often neglected. Another 10 papers only reported the outcome of implants in patients with a history of periodontitis. In case of SPT and when avoiding roughened surfaces, late implant loss remained below 3%, and marginal bone loss remained low. CONCLUSIONS: These results seem to indicate that periodontally compromised patients can be successfully treated with minimally/moderately rough implants, in the presence of SPT.     

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.     

The influence of bone mechanical properties and implant fixation upon bone loading around oral implants

Finite element models were created to study the stress and strain distribution around a solitary BAnemark implant. The influence of a number of clinically relevant parameters was examined: bone‐implant interface (fixed bond versus frictionless free contact), bone elastic properties, unicortical versus bicortical implant fixation and the presence of a lamina dura. Bone loading patterns in the vicinity of the implant seem to be very sensitive to these parameters. Hence they should be integrated correctly in numerical models of in vivo behaviour of oral implants. This necessitates the creation of patient‐dependent finite element models.     

Histomorphometric assessment in human cadavers of the peri-implant bone density in maxillary tuberosity following implant placement using osteotome and conventional techniques

Objective: To evaluate and compare peri‐implant bone condensation in the maxillary tuberosity of human cadavers following the osteotome and standard drilling techniques, and to determine whether peri‐implant bone condensation following the osteotome technique is localized or homogeneous. Material and methods: Twenty‐four cylinder‐threaded titanium implants (12 on each side) were placed in the left (standard technique) and right (osteotome technique with tapered osteotomes for bone condensation, Straumann^®) maxillary tuberosities of 12 edentulous posterior maxillae of deceased people who had bequeathed their bodies to the University of Santiago de Compostela for medical‐scientific research. After surgery, the implants were removed with the surrounding bone, prepared using sawing and grinding technique and examined histomorphometrically. The bone density (bone area/analyzed area) of the entire, periapical (fifth apical) and pericylinder peri‐implant areas was calculated, statistically analyzed and compared with the bone density of the host cancellous maxillary bone. Results: The bone density of the entire peri‐implant area was statistically found to be greater with the osteotome technique (39.38 ± 9.67) than with conventional drilling technique (31.06 ± 5.9). This difference was greatest for the periapical zone (53.32 ± 12.26 vs. 34.18 ± 6.34). Nonetheless, in the pericylinder area no significant difference was found between the two techniques (32.30 ± 8.74 vs. 30.34 ± 7.2). Conclusion: Peri‐implant bone condensation following the osteotome technique is not homogeneously observed through the entire peri‐implant area. A greater bone density was achieved only in the fifth apical peri‐implant area.     

Effect of platform switching on peri-implant bone levels: a randomized clinical trial

Objective: The concept of platform switching has been introduced to implant dentistry based on observations of reduced peri‐implant bone loss. However, randomized clinical trials are still lacking. This study aimed to test the hypothesis that platform switching has a positive impact on crestal bone‐level changes. Material and methods: Two implants with diameters of 4 mm were inserted epicrestally into one side of the posterior mandibles of 25 subjects. After 3 months of submerged healing, the reentry surgery was performed. On the randomly placed test implant, an abutment 3.3 mm in diameter was mounted, resulting in a horizontal circular step of 0.35 mm (platform switching). The control implant was straight, with an abutment 4 mm in diameter. Single‐tooth crowns were cemented provisionally. All patients were monitored at short intervals over the course of 1 year. Standardized radiographs and microbiological samples from the implants' inner spaces were obtained at baseline (implant surgery), and after 3, 4, and 12 months. Results: After 1 year, the mean radiographic vertical bone loss at the test implants was 0.53±0.35 mm and at the control implants, it was 0.58±0.55 mm. The mean intraindividual difference was 0.05±0.56 mm, which is significantly <0.35 mm (P=0.0093, post hoc power 79.9%). The crestal bone‐level changes depended on time (P<0.001), but not on platform switching (P=0.4). The implants' internal spaces were contaminated by bacteria, with no significant differences in the total counts between the test and the control at any time point (P=0.98). Conclusions: The present randomized clinical trial could not confirm the hypothesis of a reduced peri‐implant bone loss at implants restored according to the concept of platform switching. To cite this article:
Enkling N, Jöhren P, Klimberg V, Bayer S, Mericske‐Stern R, Jepsen S. Effect of platform switching on peri‐implant bone levels: a randomized clinical trial.
Clin. Oral Impl. Res. 22 , 2011; 1185–1192.
doi: 10.1111/j.1600‐0501.2010.02090.x     

Micro-morphometric assessment of titanium plasma-sprayed coating removal using burs for the treatment of peri-implant disease

This study evaluated, in vitro, the effectiveness of diamond and carbide burs, and bur sequences to remove the plasma-sprayed titanium coating from IMZ fixture surfaces. Fifteen polishing procedures were tested. They included the use of 12, 16, 30 bladed carbide burs or bevered carbide burs and 30, 15, 8 microns mean-particles-size diamond burs. The treated surfaces were evaluated with profilometer and SEM. Worn burs and titanium debris produced by the grinding were observed with SEM. All procedures produce smoother surfaces than baseline plasma-sprayed surfaces for both Ra and Rz(DIN) parameters (P < 0.001). A roughening effect of the 8 microns mean-grit diamond bur and 30 bladed burs were noted. The single carbide burs produce polished surfaces affected by waviness. Waviness was minimized by sequence or diamond bur use. The carbide bur blades were variously damaged after their use. In contrast, the grit of diamond burs was observed to be clogged by titanium debris whose amount seemed to be inversely related to the diamond mean particle size. Debris produced by diamond burs was granular whereas that produced by carbide bladed burs showed needle or flake morphology. In conclusion, the most effective titanium plasma sprayed removal were obtained by 30 microns and 15 microns mean-particle-size diamond burs, i.e. 30 microns plus 15 microns diamond burs and carbide 12 plus 16 bladed burs used in sequence.     

The influence of bone mechanical properties and implant fixation upon bone loading around oral implants.

Finite element models were created to study the stress and strain distribution around a solitary BAnemark implant. The influence of a number of clinically relevant parameters was examined: bone-implant interface (fixed bond versus frictionless free contact), bone elastic properties, unicortical versus bicortical implant fixation and the presence of a lamina dura. Bone loading patterns in the vicinity of the implant seem to be very sensitive to these parameters. Hence they should be integrated correctly in numerical models of in vivo behaviour of oral implants. This necessitates the creation of patient-dependent finite element models.     

Influence of forces on peri-implant bone

Abstract: Occlusal forces affect an oral implant and the surrounding bone. According to bone physiology theories, bones carrying mechanical loads adapt their strength to the load applied on it by bone modeling/remodeling. This also applies to bone surrounding an oral implant. The response to an increased mechanical stress below a certain threshold will be a strengthening of the bone by increasing the bone density or apposition of bone. On the other hand, fatigue micro-damage resulting in bone resorption may be the result of mechanical stress beyond this threshold. In the present paper literature dealing with the relationship between forces on oral implants and the surrounding bone is reviewed. Randomized controlled as well as prospective cohorts studies were not found. Although the results are conflicting, animal experimental studies have shown that occlusal load might result in marginal bone loss around oral implants or complete loss of osseointegration. In clinical studies an association between the loading conditions and marginal bone loss around oral implants or complete loss of osseointegration has been stated, but a causative relationship has not been shown.     

Nine- to fourteen-year follow-up of implant treatment. Part II: presence of peri-implant lesions

OBJECTIVES: The aim of this study was to analyse the proportions of peri-implant lesions at implants after 9-14 years of function. MATERIAL AND METHODS: Two hundred and ninety-four patients underwent implant therapy during the years 1988-1992 in Kristianstad County. These individuals were recalled to the speciality clinic 1 and 5 years after placement of the suprastructure. Between 2000 and 2002, 218 patients with 999 implants were examined clinically and radiographically. RESULTS: Forty-eight per cent of the implants had probing depth > or =4 mm and bleeding on probing (peri-implant mucositis). In 20.4% of the implants, the bone level was located 3.1 mm apical to the implant shoulder. Progressive bone loss (> or =1.8 mm) during the observation period was found in 7.7% of the implants. Peri-implantitis defined as bone loss > or =1.8 mm compared with 1-year data (the apical border of the bony defect located at or apical to the third thread, i.e. a minimum of 3.1 mm apical to the implant shoulder), combined with bleeding on probing and or pus, were diagnosed among 16% of the patients and 6.6% of the implants. CONCLUSION: After 10 years in use without systematic supportive treatment, peri-implant lesions is a common clinical entity adjacent to titanium implants.     

The effect of dental implant spacing on peri-implant bone using the rabbit (oryctolagus cuniculus) tibia model

PURPOSE: This study investigated the effects of implant proximity on inter-implant bone height, density, and osseointegration using digital radiography and histology. MATERIALS AND METHODS: After a feasibility study, a total of 80 endosteal implants were placed in 20 New Zealand White Rabbit tibias. With the aid of a surgical jig, four 8.5-mm implants were placed in the medial aspect of the tibial crest at inter-implant distances of approximately 1, 1.5, and 3 mm. Standardized digital radiographs using a paralleling device were made immediately after placement of implants. Implants were allowed to osseointegrate for 90 days. After this healing period, the animals were sacrificed, and the standardized radiographs were repeated. The tibias were harvested, processed, and invested in epoxy. Sagittal sections were made from each specimen for histologic evaluation. The initial and postmortem digital radiographs were evaluated for inter-implant distances, vertical bone height changes over time and between implant pairs, and bone density changes over time and between implant pairs using a computer image analysis program and computer statistics program. RESULTS: The actual inter-implant distances were consistent in a range of 0.2 mm. Bone height increased significantly from presurgical levels at all 3 locations (p < .0005). Repeated measures analysis of variance comparing change in bone height at the 3 implant pair distances showed significant differences among the 3 (p = .002). Paired t tests showed that the amount of bone growth at the 1-mm separation site was significantly greater than the 1.5-mm site (p = .026) and the 3-mm site (p = .001), whereas bone growth at the 1.5- and 3-mm sites did not show significant differences (p = .162). A repeated measures analysis of variance comparing change in bone density showed no significant differences (p > .05) among the 3 inter-implant distances for either the 8-mm position (approximately crestal bone height) or the 6-mm position (approximately 2 mm subcrestal). CONCLUSION: Within the limits of this study, it seems placing implants closely together does not adversely affect bone height or density. Conversely, it seems that placing implants closer together may increase bone growth.     

三种种植系统周边骨质吸收的对比研究

目的：用全景片评估平齐对接种植系统、平台转换种植系统边缘骨吸收的差别。方法：植入平齐对接种植体（Noble Replace）54枚,小平台转换种植体（Osstem GS）14枚,斜肩式平台转换种植体（Bicon）25枚。在种植体植入当天、负载3个月后分别进行全景片检查,测量种植体边缘牙槽骨高度,计算牙槽骨丧失量。SPSS14．0软件进行统计分析。结果：功能负载3个月后,平齐对接种植体近、远中边缘骨吸收量分别为1．88mm±1．49mm、1．81mm±1．34mm;斜肩式平台转换种植体为-0．68mm±0．99mm、-1．17mm±1．37mm;小平台转换种植体为0．53mm±1．48mm、0．74mm±0．99mm。三种种植体两两比较,P〈0．05,相互之间存在显著性差异。结论：应用平台转换技术可减少种植体边缘骨吸收,不同的平台转换设计,其保存种植体周围骨质的能力明显不同。     

The effect of whole-body vibration on peri-implant bone healing in rats

Purpose: The aim of this study was to evaluate the effect of low‐magnitude, high‐frequency (LMHF) loading, applied by means of whole‐body vibration (WBV), on peri‐implant bone healing and implant osseointegration in rat tibiae. Materials and methods: A custom‐made titanium implant was inserted into the proximal metaphysis of the tibiae of 42 rats and left to heal for 3, 7, 14 or 25 days. Half of the animals received LMHF mechanical vibration for 5 days per week (test), whereas the others served as unloaded controls. The WBV consisted of 15 consecutive frequency steps (12, 20, 30, … to 150 Hz). Each of the 15 frequencies was applied for 2000 cycles, at an acceleration of 0.3 g. In the group with a 25‐day healing period, PET images were taken at ?1 (day before surgery), 3, 5, 7, 10, 14 and 21 days of loading, after an injection of [¹⁸F]sodium fluoride, a positron‐emitting tracer. The ratio of the metabolic activity around the implants to that of a reference site (uptake ratio) was calculated as a measure of bone metabolism. Bone‐to‐implant contact (BIC) and peri‐implant bone fraction (BF) were analysed for histomorphometrical measurement. Results: The mean BIC and BF were significantly influenced by both the loading and the healing time (ANOVA, P<0.01). The PET images did not reveal any significant difference in uptake ratio between the test and the control implants. Conclusion: LMHF loading increased BIC and BF significantly. The results confirm the bone‐stimulating potential of LMHF loading, through WBV, on peri‐implant bone healing and osseointegration. To cite this article:
Ogawa T, Zhang X, Naert I, Vermaelen P. Deroose CM, Sasaki K, Duyck J. The effect of whole‐body vibration on peri‐implant bone healing in rats.
Clin. Oral Impl. Res. 22 , 2011; 302–307.
doi: 10.1111/j.1600‐0501.2010.02020.x