Number and localization of the implants for the fixed prosthetic reconstructions: on the strain in the anterior maxillary region.

Resorption following tooth loss and poor bone quality affect the success of implants in the anterior maxilla. Inappropriate planning can cause implant loss and aesthetics problems that are difficult to resolve. There is a limited literature on the optimum number and location of implants in anterior maxilla for fabricating fixed prosthesis in biomechanical terms. This study investigated the effect of dental implant localizations in anterior maxilla on the strain values around implants using a three dimensional finite elements analysis method. Obtained strain values were compared to the data in Frost's mechanostat theory. The entire totally edentulous maxilla was modeled using computer tomography images and five models were prepared representing different implant localizations. The distribution of implants in the models was as follows: two canines in the first model, two canines and one central incisor in the second model, two canines and central incisor in the third model, two canines and one lateral incisor in the fourth model and two canines and two lateral incisors in the fifth model. Anatomic abutments with a gingival height of 2 mm and angle of 15° were used as the abutments to fabricate one piece cemented metal fused to porcelain restoration. A chewing strength of 100 N was applied to the cingulum of all crowns at a 45° angle. Maximum strain values in all models were measured in cortical bone in implant necks. The highest strain value was measured in the first model at the cortical bone area (3037 microstrain). Except the first model, all models showed micro strain values within 1000-3000 microstrain. The fifth model was the least risky method in biomechanical terms. The results of this study should be compared with different clinical scenarios (for example different implant designs and sizes). Due to the limitations of three-dimensional finite elements analysis studies, the findings of the study need to be supported by clinical studies.

Effects of Light-Emitting Diode Photobiomodulation Therapy and BioOss as Single and Combined Treatment in an Experimental Model of Bone Defect Healing in Rats.

The present study assesses histopathologically and histomorphometrically the effects of light-emitting diode (LED) photobiomodulation therapy (LPT) on bone healing in BioOss-filled femoral defects of rats. It has been reported that LPT modulates cellular metabolic processes, leading to an enhanced regenerative potential for biological tissues. Thirty-six male Wistar rats with femoral bone defects were divided into 4 groups: defect group (empty bone defect, without application of LPT), graft group (bone defect filled with BioOss, without application of LPT), (defect+LPT) group (empty bone defect, with application of LPT), and (graft+LPT) group (bone defect filled with BioOss, with application of LPT). An OsseoPulse LED device (wavelength: 618 nm; output power: 20 mW/cm(2)) was initiated 24 hours postsurgery and performed every 24 hours for 7, 14, and 21 days. The LPT-applied and BioOss-filled defects presented a higher amount of new bone formation with trabeculae formation. These defects showed statistically significant lower values of inflammation severity, and fewer remnants of biomaterial were present. Within the limitations of this study, LPT has positive effects on bone healing histopathologically and histomorphometrically for the defects filled with BioOss 3 weeks after the rats' femora injury.

Sinus Augmentation With Platelet-Rich Fibrin in Combination With Bovine Bone Graft Versus Bovine Bone Graft in Combination With Collagen Membrane.

The purpose of this study was to compare the efficacy between the use of bovine bone graft material and platelet-rich fibrin (PRF) mixture (test group) and bovine bone graft material and collagen membrane combination (control group) in 2-stage maxillary sinus augmentation. According to specific inclusion/exclusion criteria, patients treated between 2008 and 2012 were selected. Panoramic radiographs were used for radiologic assessments. To evaluate the relationship between sinus-graft height and each implant, the bone level (BL) was divided by implant length (IL). To evaluate the change in the height of grafted sinus, the grafted sinus floor above the lowest part of the original sinus height (GSH) was divided by the original sinus height (OSH). Samples taken during implant surgery were used for histologic and histomorphometric analyses. Twenty-five patients, 32 augmentation surgeries, and 66 one-stage implants were included in the study. No implant loss or complication was observed in either group. There were no statistical differences according to new bone formation (P = .61) and biomaterial remnant (P = .87). During the evaluation period, the test group showed statistically less change in the BL/IL ratio (P = .022). The difference of GSH/OSH ratio was found to be insignificant between groups (P = .093). It was observed that the grafted sinus covering the implant apex and sinus floor was above the original sinus height in both groups. It may be concluded from this study that both combinations can be successfully used for sinus augmentation. Further studies evaluating different graft materials and PRF combinations in the early phases of healing would be beneficial.

Clinical and Radiographic Evaluation of Marginal Bone Changes around Platform-Switching Implants Placed in Crestal or Subcrestal Positions: A Randomized Controlled Clinical Trial.

BACKGROUND: It has been reported in many articles that marginal bone resorptions are prevented by platform-switching design. However, what occurs when these implants are placed in the apical position is not completely known. PURPOSE: This report describes a randomized controlled clinical trial study that aims to test the hypothesis that less resorption will occur when platform-switching implants are placed 1 mm below bone level. MATERIALS AND METHODS: A total of 56 randomly selected implants were inserted bilaterally, either 1 mm below bone level (test group, 28 implants) or at bone level (control group, 28 implants) of the patients' posterior regions. Marginal bone resorptions were examined through periapical radiographies taken with the parallel technique at the time of crown cementation and the third, sixth, 12th, and 36th months after prosthetic loading. The modified plaque index, gingival index, bleeding on probing, and probing depths were used for follow-up periodontal care of the implants. RESULTS: After 3 years, the mean radiographic vertical bone loss in the control group was significantly lower than in the test group (0.56 ± 0.35 mm and 1.21 ± 1.05 mm, respectively) (p < .01). In terms of periodontal indexes, there were no statistically significant differences between the two groups (p > .05). No peri-implantitis or peri-implant mucositis was observed around the test or control implants. CONCLUSIONS: More marginal bone resorptions occurred after the third year of loading in implants placed 1 mm below bone level. However, the resorptions did not reach the implants thread. In the control group, the first bone implant contact was placed under the level of the first threads. Therefore, the present randomized clinical trial confirmed the hypothesis that placing platform-switching implants 1 mm below bone level reduced marginal bone loss. It can be noted that to reduce resorption, platform-switching implants should be placed below bone level.

Topical Single-dose Vascular Endothelial Growth Factor has No Effect on Soft Tissue Healing.

BACKGROUND: Vascular endothelial growth factor (VEGF) production in dermal wounds has been evaluated for evidence that it plays a probable role in wound healing. Events such as increased vascular permeability and concentration of inflammatory cells on the site of injury, produced by VEGF, were linked to tissue repair. AIM: The present study aimed to evaluate the effects of single-dose topical administration of VEGF on wound healing. MATERIALS AND METHODS: A total of 30 male Wistar albino rats weighing 250-280 g were used in this study. In addition, 2-cm-long skin incisions were created over bilaterally exposed skin of the tibia region in each rat. VEGF plasmid 2 µg was administered locally into the right side wound bed of each animal. No other procedure besides skin closure was administered on the left side. To determine histologic assessments, skin samples were obtained from six anesthetized rats at each interval (4, 8, 12, 16 and 30 days) through excisional biopsy. The tissues were fixed in 10% neutral-buffered formalin for 1 week and then embedded in paraffin wax. Transverse sections of the embedded tissue 5-7 µm thick were stained with hematoxylin and eosin (H and E). RESULTS: There was no significant difference regarding necrosis, epithelialization, inflammation, fibroblast activity, ulcerative formation, or hemorrhage between experimental and control groups. No statistically significant difference was found between the groups regarding granulation tissue formation and epidermal thickness. CONCLUSION: The administration method and dosage of VEGF is a major factor in terms of its effectiveness. The results of the present study did not evaluate the effectiveness of single-dose 2 µg topical administration of VEGF; however, various doses of VEGF plasmid should be tested in future studies in order to provide beneficial effects from topical administration of VEGF.

The use of platelet-rich fibrin in combination with biphasic calcium phosphate in the treatment of bone defects: a histologic and histomorphometric study.

BACKGROUND: Platelet-rich fibrin (PRF) is a leukocyte and platelet concentrate containing many growth factors. Its potential for hard tissue augmentation as a sole grafting material or in combination with other grafting materials has been investigated in many studies. OBJECTIVE: The aim of this histologic study was to evaluate the efficacy of PRF mixed with biphasic calcium phosphate (BCP) on bone regeneration in surgically created bone defects. METHODS: Defects 5 mm in diameter were created in both tibias of 6 sheep. The defects were left empty or grafted with BCP, PRF, or BCP+PRF. Animals were killed at 10, 20, and 40 days. The specimens underwent histologic and histomorphometric analysis. RESULTS: None of the groups displayed any signs of necrosis. Inflammation was observed in all groups at 10 days; 2 specimens of PRF+BCP and all empty defects showed inflammatory cell infiltration at 20 days. During the 40-day evaluation period, the PRF+BCP group showed the highest ratios of new bone. The other 3 groups showed statistically similar results. In the BCP and PRF+BCP groups, the residual graft ratios were decreased at consecutive time intervals. The difference between the 2 groups was not statistically significant during follow-up. CONCLUSIONS: The current study revealed a histomorphometric increase in bone formation with the addition of PRF to BCP in surgically created defects in sheep tibia.

Computer-assisted flapless implant placement reduces the incidence of surgery-related bacteremia.

OBJECTIVE: Bacteremia--the access of bacterium to the bloodstream--may yield life-threatening complications. The aim of this study was to compare the incidence, duration, and type of bacterium leading to bacteremia with relation to conventional and computer-assisted flapless implant surgery. MATERIAL AND METHODS: A total of 377 implants were placed in 68 edentulous jaws using the conventional (conventional group) or a computer-assisted stereolithographic (SLA) template-guided surgery technique (flapless group). Bacteremia was monitored from pre- and postoperative blood samples. RESULTS: The duration of the surgical intervention was significantly shorter in the flapless group (p = 0.3510). Baseline samples were sterile. Following the 15th minute after the placement of the last implant, bacteria were present in 62 and 12 % of the patients in the conventional and flapless groups, respectively (p < 0.0001; relative risk: 3.05). The differences in the incidence of the bacteremia detected at the baseline and 15 min after the last implant placement were statistically significant in the conventional group (p = 0.0001). However, no such statistical significance was present in the flapless group. Staphylocccus epidermidis, Bifidobacterium spp., Streptococcus viridans, Corynebacterium spp., and Streptococcus sanguinis were the isolated bacterium. CONCLUSIONS: Irrespective of the utilized technique, bacteremia may occur upon the placement of four to eight implants to an edentulous jaw. The probability of bacteremia for the patients operated with the conventional technique is, however, 3.05 greater than those operated with the flapless technique. CLINICAL RELEVANCE: Flapless implant placement reduces the incidence of surgery-related bacteremia and, therefore, may be beneficial to patients at risk.

The comparison of two techniques to increase the amount of peri-implant attached mucosa: free gingival grafts versus vestibuloplasty. One-year results from a randomised controlled trial.

AIMS: The objective of this randomised controlled trial was to compare the efficacy of two techniques for increasing the amount of keratinised mucosa around implants: free gingival grafts versus classic vestibuloplasty. MATERIALS AND METHODS: Sixty-four patients with 64 implants presenting keratinised mucosa <1.5 mm and showing signs of peri-implant mucositis were randomly assigned to two groups. Thirty-two implants received free gingival grafts (FGG group) while 32 implants were treated via vestibuloplasty (VP group). Plaque Index (PI), Gingival Index (GI), probing depth (PD) and the width of attached mucosa (WAM) were measured at baseline and 1, 3, 6 and 12 months following surgery. RESULTS: WAM in the FGG group was significantly greater than the VP group at 3, 6 and 12 months (P = 0.000). In the FGG group, the final gain in WAM was greater (2.36 mm in FGG group, 1.15 mm in VP group) (P = 0.000) and the postoperative relapse was smaller (2.00 mm in FGG group, 3.06 mm in VP group) (P = 0.000). The VP group had higher PD values at 3, 6 and 12 months (P = 0.02, P = 0.024, P = 0.000, respectively). CONCLUSIONS: The application of FGG is a more predictable method for enhancing the width of attached mucosa in the vicinity of implants compared with classic vestibuloplasty.

Efficacy of quick-release lornoxicam versus placebo for acute pain management after dental implant surgery: a randomised placebo-controlled triple-blind trial.

AIM: To assess the efficacy of quick-release lornoxicam (LNX) on patient-reported acute pain after dental implant surgery. MATERIALS AND METHODS: The study included subjects in good general health, aged 18 to 65 and scheduled to receive a maximum of three implants in the same quadrant. Participants received either 8 mg LNX or placebo and were asked to use the medications in case of pain in the first 120 min after implant surgery. Assessment of efficacy was performed using self-assessment questionnaires for the evaluation of pain intensity and pain relief for 12 h post dosing. Patients were also asked to record the rescue analgesic number. Evaluation of patient satisfaction was assessed using a 7-point scale. Safety was evaluated by the incidence of adverse events. RESULTS: A total of 83 (LNX/placebo, 42/41) patients who met the inclusion criteria and finished the evaluation period were included in the study. The proportion of patients experiencing postoperative pain was significantly lower in the LNX-treated group compared to the placebo group. Patients in the LNX group reported significantly higher pain relief scores than the placebo group. Twenty-nine patients in the placebo group and 6 patients in the LNX group used rescue analgesics. The number of used rescue analgesics was 1.024 ± 0.79 and 0.167 ± 0.43 in the placebo and LNX groups, respectively. The level of patient satisfaction was significantly higher in the LNX-treated patients (P = 0.007). No adverse events were reported during the study period. CONCLUSIONS: Quick-release LNX is effective in postoperative acute pain control and has a high safety profile following dental implant surgery.

Bacteremia following dental implant surgery: preliminary results.

OBJECTIVES: The aims of this study were to investigate the incidence of bacteremia, bacteriology and antibiotic susceptibility against to causative bacteria associated with dental implant installation. STUDY DESIGN: 30 generally healthy patients were enrolled in this study. Blood samples were collected at baseline and at 30 minutes after dental implant installation and 24 hours after dental implant surgery. Blood samples were cultured in a BACTEC system. The isolated bacteria were identified using conventional methods. Antimicrobial sensitivity tests were performed by disc diffusion. RESULTS: No bacteria were isolated at the baseline and 24 hours after surgery, whereas the prevalence of bacteremia at 30 minutes after dental implant installation was 23%. The isolated bacteria species were Staphylococcus epidermidis, Eubacterium spp., Corynebacterium spp. and Streptococcus viridans. The Staphylococcus epidermidis, which was isolated in three patients, was found to be resistant to penicillin which is first choice of many clinicians. CONCLUSION: Our findings suggest that installation of dental implants can produce bacteremia. Within the limitations of this study, it can be speculated that the resistance of antibiotics may compromise the routine prophylaxis against infective endocarditis. Therefore use of blood cultures and antibiograms may be suggested in risky patients. The outcome of the present study should be verified using a larger patient group with varying conditions.

Evaluation of 316 narrow diameter implants followed for 5-10 years: a clinical and radiographic retrospective study.

OBJECTIVES: Narrow diameter implants (NDIs; diameter >3.75 mm) are useful in replacement of missing incisor teeth and when the bucco-lingual width of the edentulous crest is insufficient. The present study evaluated the success and survival rates, peri-implant parameters, mechanical and prosthetic post-loading complications of NDIs followed over a 10-year period. MATERIAL AND METHODS: Three hundred and sixteen NDIs were inserted into 139 patients and restored with 120 prostheses. Clinical and radiographic assessment data were collected during recall visits. Implant success (SC), cumulative survival rate (CSR), marginal bone loss (MBL), peri-implant conditions and prosthetic complications were assessed. Cox proportional hazards regression analysis, Kaplan-Meier survival curves with the log-rank test and life table analysis were used to evaluate the outcome of NDIs within comparable subgroups. MBL and peri-implant parameters measured annually were further analyzed. RESULTS: The mean follow-up time was 9.1 years (range: 60-124 months). Twelve implants were lost in the healing phase and two during function. The mean MBL in the maxilla and the mandible was 1.32 +/- 0.13 and 1.28 +/- 0.3 mm, respectively, after 10 years. SC and CSR were 91.4% and 92.3%, respectively, after 124 months. Smoking and posterior localization were associated with an increased risk of failure. Cement loosening (16.8%) was the most common prosthetic complication. No implants were fractured. CONCLUSIONS: NDIs can be used with confidence where a regular diameter implant is not suitable. MBL around NDIs occurred predominantly within 2 years of loading and was minimal thereafter. Further studies are required to clarify the possible risks associated with smoking and posterior placement.

Comparison of analgesic and anti-inflammatory efficacy of selective and non-selective cyclooxygenase-2 inhibitors in dental implant surgery.

BACKGROUND: The analgesic and anti-inflammatory efficacy of tenoxicam and meloxicam were evaluated in this double-masked, randomized, prospective study by analyzing pain scores and the need for rescue-analgesic agents following dental implant surgery. METHODS: One hundred patients, in whom 241 dental implants were placed, were divided into two groups. For 4 days beginning the day before surgery, the first group received meloxicam, 15 mg daily, and the second group received tenoxicam, 20 mg daily, followed by 1 hour preoperatively and for 2 days thereafter. Pain intensity was rated by the subjects based on a visual analog scale on the operation day and on the following 6 days. The patients were recommended to use a rescue analgesic if the pain score was > or =4. Postoperative complications, such as edema, hematoma, infection, severe pain, paresthesia, or gastrointestinal complaints, were also noted. RESULTS: Statistical analysis revealed that 54% of patients in the tenoxicam group and 66% of patients in the meloxicam group used rescue analgesics on day 1. However, the difference between the groups was not significant (chi(2) = 1.05; P = 0.30). The relationship between the reduction of consumption and time was not significant in either group (Z = 0.84; P = 0.40). The relationship between the use of rescue analgesics and the number of implants placed was not significant. Among patients who reported postoperative complications, there was not a statistically significant difference between the groups (chi(2) = 0.04; P = 0.84). CONCLUSION: Meloxicam and tenoxicam exhibited a similar analgesic and anti-inflammatory efficacy in the present investigation.

Clinical performance of sealants with and without a bonding agent.

OBJECTIVES: The objective of this study was to assess the effect of a one-bottle bonding agent on sealant success after 3, 6, 12, and 24 months. METHOD AND MATERIALS: The sample group consisted of 30 schoolchildren (8 to 10 years of age) who had all their permanent first molars sound and unsealed. Occlusal sealants were placed on first molars according to a split-mouth design. Sealant scoring occurred at 3, 6, 12, and 24 months and was performed by two clinicians blinded to the treatment group. Fisher's exact test was used to analyze the data. RESULTS: The clinically acceptable marginal integrity rates for sealants with a bonding agent after 3, 6, 12, and 24 months were 93%, 93%, 83%, and 79%, respectively. For sealants without a bonding agent, the clinically acceptable marginal integrity rates after 3, 6, 12, and 24 months were 90%, 88%, 81%, and 77%. The rates for no color change in sealants with a bonding agent after 3, 6, 12, and 24 months were 96%, 93%, 81%, and 75%, respectively. For sealants without a bonding agent, the no color change rates after 3, 6, 12, and 24 months were 93%, 93%, 79%, and 72%. After 24 months, 73% of the sample group were available for recall. The retention rates for sealants with and without a bonding agent after 24 months were 79% and 75%, respectively. The results of the statistical analysis showed that there were no differences among the sealants with and without bonding agents evaluated in relation to marginal integrity, marginal discoloration, and anatomic form. CONCLUSION: The success of a sealant is related to whether the sealant is applied under optimal conditions. The results of this study show that at the 2-year mark, the placement of a bonding agent under sealants did not significantly affect the clinical success of sealants.