Avoiding implant-related complications in medically compromised patients with or without unhealthy lifestyle/Elevated oxidative stress.

Increased human life expectancy broadens the alternatives for missing teeth and played a role in the widespread use of dental implants and related augmentation procedures for the aging population. Though, many of these patients may have one or more diseases. These systemic conditions may directly lead to surgical complications, compromise implant/bone healing, or influence long-term peri-implant health and its response to biologic nuisances. Offering patients credible expectations regarding intra- and postoperative complications and therapeutic prognosis is an ethical and legal obligation. Clear identification of potential types of adverse effects, complications, or errors is important for decision-making processes as they may be related to different local, systemic, and technical aspects. Therefore, the present review structures the underlying biological mechanisms, clinical evidence, and clinical recommendations for the most common systemic risk factors for implant-related complications.

Influence of Implant Length and Associated Parameters Upon Biomechanical Forces in Finite Element Analyses: A Systematic Review.

PURPOSE: The aim of this systematic review is to provide an overview of finite element analyses comparing standard and short dental implants concerning biomechanical properties and to detect the most relevant parameters affecting periimplant stress concentrations. MATERIAL AND METHODS: After screening the literature and assessment of studies, 36 studies were included in this review. RESULTS: Eighty-three percent of the studies state that short dental implants have to bear higher stress concentrations compared with standard length implants. At the same time, 44% of articles note that implant diameter can be considered a more effective design parameter than implant length to reduce stress concentrations and to avoid an overload of periimplant bone. Regardless of implant dimension, in all studies, the highest stress concentrations are found in the cortical section around the upper part of the implant. CONCLUSIONS: Unaffected of bone quality, implant diameter is found to play a key role to minimize periimplant stress concentrations. Concerning stress reduction implant length gains increasing relevance with decreasing bone density. Furthermore, splinting of short implants constitute an appropriate tool to avoid crestal overloading.

Periimplantitis Treatment: Long-Term Comparison of Laser Decontamination and Implantoplasty Surgery.

PURPOSE: Periimplantitis is the most frequent cause of late implant failure; however, little is known about the long-term success of periimplantitis treatment and the effectiveness of various therapeutic interventions. MATERIALS AND METHODS: A total of 142 patients were referred to the Academy for Oral Implantology in Vienna for the treatment of recurrent periimplantitis around single-tooth implants. Of them, 72 patients (51%) were treated by laser decontamination, 47 patients (33%) by implantoplasty surgery, and 23 patients (16%) by a combination of both approaches. RESULTS: Overall success of periimplantitis therapy was 89% after 9 years of follow-up, and it did not differ significantly between female and male patients (P = 0.426). The number of implant failures that could not be prevented by periimplantitis treatment was 6 after laser decontamination (8%), 6 after implantoplasty surgery (13%), and 4 after a combination of both therapies (17%). Implant loss occurred after 4.9 ± 1.9 years of therapy, on average. No significant difference between the 3 treatment groups could be observed (P = 0.393). CONCLUSION: The present results suggest that success rates of periimplantitis therapy with either laser decontamination or surgical implantoplasty are high. These success rates do not appear to be associated with patient gender or treatment strategy.

Dental implants are a viable alternative for compensating oligodontia in adolescents.

OBJECTIVES: To clinically and radiographically evaluate dental implant treatment in adolescents with extensive oligodontia. METHODS: Patients with more than nine permanent teeth congenitally missing and implant treatment before the age of 16 years were included. Clinical follow-ups involved bleeding on probing, plaque index and peri-implant probing value. The peri-implant bone level was analysed on panoramic radiographs at time of implant treatment and at follow-up. Characteristics of the dental implants and patients were retrieved. RESULTS: This study involved 18 patients (nine males, nine females) having 71 dental implants. The lower left premolar was predominantly missing. The mean age at the time of dental implant treatment was 12.5 (± 2.6) years. The bleeding on probing value was determined negative on 44%. The mean pocket depth was 3.6 (± 1.1) mm. The peri-implant bone level correlated significantly negative with the age at time of implant placement (r = -0.346, P = 0.004). The region of implant habits had no influence on peri-implant bone level. Dental implant treatment in adolescents resulted in a survival rate of 89% (63/71) and a mean loading time of 11.0 (± 4.1) years. The implant crowns to be renewed resulted in 54% (9 of 18 patients, 38 of 71 crowns) after a period of 7.8 ± 4.5 years. CONCLUSION: Dental implant treatment in maturing adolescents with extensive oligodontia before is supported by the data of the present study. Providing that other treatment options are considered, the areas of skeletal growth are respected and the patients are well informed. To enhance quality of life of growing children with oligodontia clinicians are asked to evaluate their long-term outcome on dental implant treatment in adolescents.

In vitro adhesion of fibroblastic cells to titanium alloy discs treated with sodium hydroxide.

OBJECTIVE: Adhesion of osteogenic cells on titanium surfaces is a prerequisite for osseointegration. Alkali treatment can increase the hydrophilicity of titanium implant surfaces, thereby supporting the adhesion of blood components. However, it is unclear if alkali treatment also supports the adhesion of cells with a fibroblastic morphology to titanium. MATERIALS AND METHODS: Here, we have used a titanium alloy (Ti-6AL-4V) processed by alkali treatment to demonstrate the impact of hydrophilicity on the adhesion of primary human gingival fibroblast and bone cells. Also included were the osteosarcoma and fibroblastoma cell lines, MG63 and L929, respectively. Cell adhesion was determined by scanning electron microscopy. We also measured viability, proliferation, and protein synthesis of the adherent cells. RESULTS: Alkali treatment increased the adhesion of gingival fibroblasts, bone cells, and the two cell lines when seeded onto the titanium alloy surface for 1 h. At 3 h, no significant changes in cell adhesion were observed. Cells grown for 1 day on the titanium alloy surfaces processed by alkali treatment behave similarly to untreated controls with regard to viability, proliferation, and protein synthesis. CONCLUSION: Based on these preliminary In vitro findings, we conclude that alkali treatment can support the early adhesion of cells with fibroblastic characteristics to a titanium alloy surface.

Risk Factors of Membrane Perforation and Postoperative Complications in Sinus Floor Elevation Surgery: Review of 407 Augmentation Procedures.

PURPOSE: To test patient- and sinus-related risk factors for an association with intraoperative membrane perforation and postoperative complications after sinus floor augmentation surgery. MATERIALS AND METHODS: Sinus floor elevation procedures using a lateral approach were retrospectively analyzed for patients' medical history and sinus anatomy on computed tomographic scans. Complications per sinus after membrane elevation and augmentation using a mixture of autologous bone and deproteinized bovine bone substitute (Bio-Oss) were recorded. Logic regression (adjusted using the generalized estimation equation approach) was performed to analyze the influence of patient age, gender, smoking habits, sinus septa, residual bone height, and mesiodistal elevation width. RESULTS: Of 407 sinus grafts in 300 patients (mean age, 56 yr), perforation of the Schneiderian membrane occurred in 35 sinuses (8.6%) and was significantly associated to the presence of sinus septa (odds ratio [OR] = 4.8; P = .002) and decreased residual bone height (OR = 0.01; P < .001). Smoking increased the risk of membrane perforation (OR = 4.8; P = .002), sinusitis (OR = 12.3; P < .001), and wound dehiscence (OR = 16.1; P = .005). Cases of sinus membrane perforation had higher odds for postoperative sinusitis (OR = 10.5; P < .001). The probability of wound dehiscence increased with the size of the elevated area (OR = 3; P < .001). CONCLUSION: The results of the study suggest that the presence of sinus septa and residual bone height less than 3.5 mm are the main risk factors increasing sinus membrane perforation rates. There was a higher prevalence for sinusitis in cases of membrane perforation (31.4%) despite intraoperative closure with resorbable membranes (Bio-Guide). Smokers generally exhibited greater chances for complications.

Bone formation in peri-implant defects grafted with microparticles: a pilot animal experimental study.

AIM: This study aimed to evaluate the healing of peri-implant defects grafted with microparticles (MPs). MATERIAL AND METHODS: Six domestic pigs received nine standardized defects at the calvaria, and an implant was inserted in the middle of each defect. The space between the implant and lateral bone portion was filled with MP pellets (n = 18) or MP supernatant (n = 18) or left unfilled (n = 18). After 14 and 28 days, three animals were sacrificed and specimens removed for further processing. Samples were microradiographically and histologically analysed. In addition, we immunohistochemically stained for anti-vWF as a marker of angiogenesis. RESULTS: In the case of bone regeneration and vessel formation, the null hypothesis can be partially rejected. After 14 and 28 days, no significant difference was observed within groups regarding de novo bone formation, bone density and osseointegration. However, superior vessel formation was found at both time points. CONCLUSION: Microparticles represent a promising treatment option to accelerate peri-implant vessel formation. Further studies are needed to investigate the regenerative properties of MPs more precisely.

Primary implant stability in the atrophic sinus floor of human cadaver maxillae: impact of residual ridge height, bone density, and implant diameter.

OBJECTIVES: Simultaneous implant placement in conjunction with lateral or transcrestal maxillary sinus floor augmentation gives the benefit of reduction in healing times and surgical interventions. Primary implant stability, however, may be significantly reduced in resorbed residual ridges. Aim of the present study was to investigate the impact of residual bone height, bone density, and implant diameter on primary stability of implants in the atrophic sinus floor. MATERIAL AND METHODS: A total of 66 NobelActive implants were inserted in the sinus floor of fresh human cadaver maxillae: 22 narrow (3.5 mm), 22 regular (4.3 mm), and 22 wide (5.0 mm) diameter implants in residual ridges of 2-6 mm height. Presurgical computed tomographic scans were acquired to assess bone height and density. Primary implant stability was evaluated by insertion torque values (ITV), Periotest values (PTV), and Osstell implant stability quotients (ISQ). RESULTS: Correlations within outcomes (ITV, PTV, ISQ) were highly significant (P < 0.001). Radiographic bone density was found to significantly impact all three outcome measures (P < 0.001), while no influence of residual bone height and implant diameter could be revealed by multifactorial analysis. Consistent results were seen in all subgroups (including residual ridges of 5-6 mm height). CONCLUSIONS: Bone density seems to represent the major determinant of primary stability in maxillary sinus augmentation with simultaneous implant placement (as well as 5-6 mm short implants in the maxillary sinus floor). Preoperative bone density assessment may help to avoid stability-related complications in one-stage implant treatment of the atrophic posterior maxilla.

Patients' perspectives on dental implant and bone graft surgery: questionnaire-based interview survey.

PURPOSE: To assess up-to-date expectations and preferences of patients seeking dental implants. MATERIAL AND METHODS: One hundred and fifty consecutive patients (66 male and 84 female interviewees) were asked to rank their concerns regarding implant therapy and answer a questionnaire on implant and bone graft surgery, cost and time considerations and second-opinion behaviour. RESULTS: Treatment predictability and avoidance of removable dentures were ranked high priority (compared with time and cost efficiency or avoidance of bone grafts). Patients' estimation of the 10-year implant success rate was 84%, and 59% of patients expected implants to last for a lifetime. Total treatment time was estimated to be 4 months on average, and only 12% would tolerate increased risk of implant failure for the sake of shortening treatment duration. 61% of interviewees accepted autologous bone grafts (the majority favouring the retromolar area), while only 23% were willing to undergo bone harvesting from the hip. 43% opted for bone substitute material to avoid donor site morbidity. 67% would accept the additional costs associated with computed tomography, software-based treatment planning and guided implant placement to avoid bone graft surgery. Motivation for second-opinion seeking was high (46-62%), especially in young and male patients. CONCLUSION: Patient expectations on implant success and predictability are high compared with their reluctance towards treatment costs and duration. Acceptance of treatment morbidity is high among patients reporting low denture satisfaction; however, minimally invasive treatment alternatives are generally preferred.

Esthetic evaluation of single-tooth implants in the anterior mandible.

OBJECTIVES: Single-tooth replacement of anterior mandibular teeth is frequently complicated by insufficient bucco-lingual bone width and limited mesio-distal space available for implant placement. The aim of the present study was to assess implant esthetics in the partially edentulous anterior mandible. MATERIAL AND METHODS: Esthetic evaluation of 43 anterior mandibular single-tooth implants in 15 women and 28 men was performed using esthetic indices (PES = Pink Esthetic Score, PI = Papilla Index, SES = Subjective Esthetic Score) as well as subjective patients' Visual Analogue Scale (VAS) ratings. Clinical and radiological parameters (implant and crown dimensions, pocket depth, bleeding on probing, plaque, keratinized mucosa, marginal bone level, and distance to adjacent teeth) were tested for influence. RESULTS: Implant esthetics were judged satisfactory (PES ≤10) in 42% of implants compared with a patient satisfaction rate of 87%. Correlation between objective indices (PES/PI: rs  = 0.62, PES/SES: rs  = -0.73, PI/SES: rs  = -0.48) was highly significant (P ≤ 0.001); however, no association to subjective patients' ratings could be observed. Type of prosthetic restoration (single crown vs. tulip-shaped double crowns), mesio-distal crown width as well as anatomic crown length significantly affected esthetic scores. Patients' judgment, by contrast, could not be associated to any prognostic factor. CONCLUSION: Subjective patient satisfaction with implant esthetics in the partially edentulous anterior mandible is high, however, remains hard to predict or objectively quantify.

A novel standardized bone model for thermal evaluation of bone osteotomies with various irrigation methods.

OBJECTIVES: Based on a novel standardized bovine specimen, the aim of this study was to investigate thermal effects of different irrigation methods during intermittent and graduated drilling. MATERIAL AND METHODS: Temperature changes during implant osteotomies (n = 320) of 10 and 16 mm drilling depths with various irrigation methods were investigated on manufactured uniform bone samples providing homogenous cortical and cancellous areas and analogous thermal conductivity comparable to human bone. Automated sequences were performed with surgical twist drills of 2 mm ∅ and conical drills of 3.5, 4.3 and 5 mm ∅. Real-time recording of temperature increase was done using two custom-built multichannel thermoprobes with 14 temperature sensors at a predefined distance of 1 and 2 mm to the final osteotomy. The effects of drilling depth, drilling diameter and irrigation methods on temperature changes were investigated by a linear mixed model. RESULTS: Using this uniform bone specimen, the greatest temperature rise was observed without any coolant supply with 29.87°C, followed by external with 28.47°C and then internal with 25.86°C and combined irrigation with 25.68°C. Significant differences (P ≤ 0.0156) between drill depths of 10 vs. 16 mm could be observed with all irrigation methods evaluated. With each of the irrigation methods, significantly higher temperature changes (P < 0.0001) during osteotomies could be observed between twist drills of 2 mm ∅ and conical drills of 3.5, 4.3 and 5 mm ∅. During 10 and 16 mm drilling osteotomies, external irrigation showed significantly higher temperatures (P < 0.05) for all conical drills compared with internal or combined irrigation, respectively. Significantly lower temperatures (P < 0.05) could be detected with internal or combined irrigation for the use of conical drills with various diameters and drilling depths. CONCLUSIONS: This fully standardized bone model provides optimized comparability for the evaluation of bone osteotomies and resulting temperature changes. As regards the efficiency of the various irrigation methods, it could be demonstrated that internal and combined irrigation appears to be more beneficial than external irrigation.

Thermal effects of a combined irrigation method during implant site drilling. A standardized in vitro study using a bovine rib model.

OBJECTIVES: The purpose of this study was to evaluate the temperature changes during implant osteotomies with a combined irrigation system as compared to the commonly used external and internal irrigation under standardized conditions. MATERIAL AND METHODS: Drilling procedures were performed on VII bovine ribs using a computer-aided surgical system that ensured automated intermittent drilling cycles to simulate clinical conditions. A total of 320 drilling osteotomies were performed with twist (2 mm) and conical implant drills (3.5/4.3/5 mm) at various drilling depths (10/16 mm) and with different saline irrigation (50 ml/min) methods (without/external/internal/combined). Temperature changes were recorded in real time by two custom-built thermoprobes with 14 temperature sensors (7 sensors/thermoprobe) at defined measuring depths. RESULTS: The highest temperature increase during osteotomies was observed without any coolant irrigation (median, 8.01°C), followed by commonly used external saline irrigation (median, 2.60°C), combined irrigation (median, 1.51°C) and ultimately with internal saline irrigation (median, 1.48°C). Temperature increase with different drill diameters showed significant differences (P < 0.05) regarding drill depth, confirming drill depth and time of drilling as influencing factors of heat generation. Internal saline irrigation showed a significantly smaller temperature increase (P < 0.05) compared with combined and external irrigation. A combined irrigation procedure appears to be preferable (P < 0.05) to an external irrigation method primarily with higher osteotomy depths. CONCLUSIONS: Combined irrigation provides sufficient reduction in temperature changes during drilling, and it may be more beneficial in deeper site osteotomies. Further studies to optimize the effects of a combined irrigation are needed.

Impact of implant surface topography: a clinical study with a mean functional loading time of 85 months.

OBJECTIVE: Moderately rough, surfaced implants are widely used. Nevertheless data on long-term soft and hard tissue parameters are still conflicting. The purpose of this study was to evaluate peri-implant bone level and soft tissue integration of anodized vs. turned surfaced implants in the anterior mandible after a mean functional loading time of 85 months. METHODS: Of 114 edentulous patients invited for follow-up, 41,2% were available for recall. Forty-seven patients with a mean age of 71 ± 9 years (14 men and 33 women) received 188 dental implants; All patients were edentulous and prosthetic rehabilitation was carried out by a bar-retained overdenture. Radiographic peri-implant bone level was assessed twice at baseline and recall. Clinical examination contained peri-implant sounding (PPD, BoP) and indexing oral hygiene (mPI). RESULTS: From baseline up to 85 months two patients experienced implant loss (four implants), which corresponds to an overall-survival rate of 97.9%. No significant differences were found between implant surfaces concerning the clinical parameters, such as plaque, calculus, bleeding on probing and pocket probing depth. The moderately rough surfaced implants showed significantly less decrease in peri-implant bone level (1.53 ± 0.25 mm) than turned surfaced implants (2.42 ± 0.34 mm) (P = 0.036). The interaction between the position of the implant and surface topography (P = 0.037) as well as the site at the implant (P = 0.004) had a significant influence on bone level changes. CONCLUSION: Both surface topographies with bar-supported overdentures have excellent long-term clinical outcomes. Moreover, a moderately roughened, anodized surface has beneficial effects in the anterior lower jaw.

Bone healing around titanium implants in two rat colitis models.

OBJECTIVE: Crohn's disease is a chronic inflammatory process that has recently been associated with a higher risk of early implant failure. Herein we provide information on the impact of colitis on peri-implant bone formation using preclinical models of chemically induced colitis. METHODS: Colitis was induced by intrarectal instillation of 2,4,6-trinitro-benzene-sulfonic-acid (TNBS). Colitis was also induced by feeding rats dextran-sodium-sulfate (DSS) in drinking water. One week after disease induction, titanium miniscrews were inserted into the tibia. Four weeks after implantation, peri-implant bone volume per tissue volume (BV/TV) and bone-to-implant contacts (BIC) were determined by histomorphometric analysis. RESULTS: Cortical histomorphometric parameters were similar in the control (n = 10), DSS (n = 10) and TNBS (n = 8) groups. Cortical BV/TV was 92.2 ± 3.7%, 92.0 ± 3.0% and 92.6 ± 2.7%. Cortical BIC was 81.3 ± 8.8%, 83.2 ± 8.4% and 84.0 ± 7.0%, respectively. No significant differences were observed when comparing the medullary BV/TV and BIC (19.5 ± 6.4%, 16.2 ± 5.6% and 15.4 ± 9.0%) and (48.8 ± 12.9%, 49.2 ± 6.2 and 41.9 ± 11.7%), respectively. Successful induction of colitis was confirmed by loss of body weight and colon morphology. CONCLUSIONS: The results suggest bone regeneration around implants is not impaired in chemically induced colitis models. Considering that Crohn's disease can affect any part of the gastrointestinal tract including the mouth, our model only partially reflects the clinical situation.

The prevalence of root resorption of maxillary incisors caused by impacted maxillary canines.

OBJECTIVES: The aim of this study was to evaluate the prevalence of root resorption of maxillary incisors caused by impacted maxillary canines using low-dose dental computed tomography and to gain additional knowledge of the underlying aetiology and the progression of root resorption. MATERIALS AND METHODS: A total of 440 patients (mean age, 24.7 years) with 557 impacted maxillary canines were examined regarding their location and the occurrence of root resorption of maxillary incisors. RESULTS: The frequency of root resorption was 2 % of central and 7.7 % of lateral maxillary incisors. The location of the 557 impacted canines within the dental arch was palatal in 67.5 %, buccal in 15.4 % and central in 17.1 %. No significant differences could be shown with respect to the width and the shape of the dental follicle of the impacted maxillary canines and the presence of root resorption of incisors. The presence of root resorption of central (p < 0.0001) and lateral (p < 0.023) maxillary incisors was significantly correlated with an existing contact relationship of the impacted maxillary canines. CONCLUSIONS: Our investigation confirms the theory of prior reports comprising a much larger patient population, hypothesising that the dental follicle of impacted maxillary canines does not cause resorption of adjacent maxillary incisors per se. CLINICAL RELEVANCE: Root resorption of maxillary incisors is correlated with effects of contact of the impacted maxillary canines, and these findings should be considered in treatment planning. Our findings are consistent with other reports and may develop new treatment approaches for the treatment of this sequela.

Prevalence, location and morphology of maxillary sinus septa: systematic review and meta-analysis.

AIM: To gain further insights and resolve conflicting results in the literature regarding prevalence, predominant location and morphologic variability of maxillary sinus septa. MATERIAL AND METHODS: Electronic and hand searching of English literature identified 33 investigations published from 1995 to 2011. Septa were defined as at least 2-4 mm in height. RESULTS: Septa were present in 28.4% of 8923 sinuses investigated (95% confidence interval: 24.3-32.5%). Prevalence was significantly higher in atrophic sinuses compared with dentate maxillae (p < 0.001). Septa were located in premolar, molar and retromolar regions in 24.4%, 54.6% and 21.0% respectively. Orientation of septa was transverse in 87.6%, sagittal in 11.1% and horizontal in 1.3% of cases. Septa height measured 7.5 mm on average. Complete septa (dividing the sinus into two separate cavities) were found in only 0.3%. Other rare conditions included multiple septa in one sinus (4.2%) and bilateral septa (17.2%). Septa diagnosis using panoramic radiographs yielded incorrect results in 29% of cases. CONCLUSIONS: In view of their high overall prevalence and significant morphologic variability, 3D radiographic imaging prior to sinus floor augmentation may help to reduce complication rates in the presence of maxillary sinus septa.

The use of onplants and implants in children with severe oligodontia: a retrospective evaluation.

OBJECTIVE: To evaluate a stable treatment concept for the oral rehabilitation of children with severe oligodontia. The treatment is intended to solve a specific problem caused by limited skeletal growth, multiple congenital missing teeth, underdeveloped bone volume and young age. MATERIAL AND METHODS: A surgical/prosthodontic approach was chosen for six patients with subtotal edentulism despite their young age. To support removable dentures the maxilla was treated with onplants (OnPlant), whereas dental rootform implants (NobelReplace, Nobel Biocare) were placed in the mandible. RESULTS: Eight onplants were placed in the hard palate of four patients for rehabilitating the maxilla and eight dental rootform implants were placed interforaminally in three patients to rehabilitate the mandible. While none of the rootform implants was lost, one onplant was lost and replaced with a stable outcome. The mean follow-up time of the onplants was 5 (±1) years vs. 3 (±2) years for the rootform implants. CONCLUSION: The evaluation showed the treatment concept described to ensure stable oral rehabilitation and recovery of the stomatognathic system even during the juvenile growth period.

Resorption of deproteinized bovine bone mineral in a porcine calvaria augmentation model.

OBJECTIVES: The original aim of the study was to determine the osteoconductive capacity of deproteinized bovine bone mineral (DBBM) of different particle sizes underneath acrylic hemispheres in vivo. However, the model failed and allowed us to report on the resorption of DBBM. MATERIAL AND METHODS: Acrylic hemispheres were filled with and without a DBBM at a small particle size of 125-250 µm and at the regular particle size of 250-1000 µm. The hemispheres were positioned on the calvaria of eight minipigs. Histological and histomorphometric analysis was performed after 12 weeks. RESULTS: We found that the acrylic hemispheres were displaced and a dense fibrous capsule sequestered the augmented area. Histology showed severe resorption activity and the presence of multinucleated cells on the surface of DBBM particles in areas adjacent to the fibrous capsule. Histomorphometric analysis revealed that only less than half of the originally augmented area, which was approximately 30 mm(2) , remained after 12 weeks. The amount of residual DBBM (median 0.9 and 3.49 mm(2)) and bone (median 7.22 and 7.51 mm(2)) in the augmented area was similar in the small and the regular particle size group. CONCLUSION: The model represents a pathologic situation of excess resorption of DBBM and bone in an augmented area. The underlying cellular mechanisms remain to be uncovered.

The influence of alendronate on osseointegration of nanotreated dental implants in New Zealand rabbits.

OBJECTIVES: Growing clinical demands for stronger and faster bone bonding to the implant have motivated the development of methods enhancing osseointegration. Lately, the application of bisphosphonates (bis) in order to optimize bone healing has become a topic of great interest. N-containing bis, such as alendronate (ALN), are the more potent drugs of this class. It was the aim of this study to determine the effect of ALN on the osseointegration of a well-documented nanotreated implant system in a rabbit femoral condyle model. MATERIAL AND METHODS: Thirty-two adult female New Zealand White rabbits received one implant (3.25 mm in diameter and 10 mm in length) in their left femoral condyle, a week after they were ovariectomized. Half of them were saline treated (control, group A) and the other half were ALN treated (group B). Rabbits from both groups were euthanized after 6 and 12 weeks, respectively. RESULTS: The specimens were evaluated histologically and histomorphometrically. Upon histological evaluation, no obvious differences were found between the control and the treatment group. Implants showed good integration into the bone tissue surrounding them. There were also no statistically significant differences in bone-to-implant contact and the amount of bone tissue in the immediate neighborhood of the implant at both healing periods. CONCLUSIONS: The systemic administration of ALN was not found to affect histological osseointegration of implants in animals with a hormonal status resembling that of postmenopausal healthy women. Further research will be needed to investigate this approach.

Impact of dietary vitamin D on osseointegration in the ovariectomized rat.

AIM: Vitamin D deficiency is highly prevalent in the population and associated with impaired peri-implant bone regeneration. Yet, there is a gap in understanding the impact of vitamin D supplementation on the process of osseointegration. In this study, the effect of vitamin D supplementation on peri-implant bone regeneration was investigated. METHODS: Fifty ovariectomized Sprague-Dawley rats were divided into three groups. The depletion group was fed a vitamin D-free diet for 8 weeks. The repletion group received vitamin D-free diet for 6 weeks, before animals were switched to standard diet containing 2400 IU/kg vitamin D. The control group was fed the standard diet. Two titanium mini-implants were placed in the tibia. All groups remained on their previous diet until sacrifice. Blood sample testing and histomorphometric analysis were performed. RESULTS: Vitamin D depletion caused a significant reduction in 25-hydroxvitamin D in rat serum that returned to control levels in the repletion group. This vitamin deficiency was associated with a decrease in bone-to-implant contact in the cortical area, which was leveled to controls in the repletion group. No significant changes by vitamin D depletion were noticed in the medullar compartment. Moreover, also the peri-implant bone area and the mineral apposition rate remained unchanged upon vitamin D depletion. CONCLUSION: These results indicate that vitamin D deficiency has a negative impact on cortical peri-implant bone formation in ovariectomized rats, which can be compensated by vitamin D supplementation. This study provides first insight into the potential beneficial effect of vitamin D supplementation in implant dentistry.