Antibiotic prophylaxis at dental implant placement: Which is the best protocol? A systematic review and network meta-analysis.

AIM: This systematic review of randomized controlled trials (RCTs) aims to answer to the following question: "In patients undergoing dental implant placement, which is the best antibiotic prophylaxis protocol to prevent early failures?" MATERIALS AND METHODS: The MEDLINE, SCOPUS, CENTRAL and Web of Knowledge electronic databases were searched in duplicate for RCTs up to July 2017. Additional relevant literature was identified through (i) handsearching on both relevant journals and reference lists, and (ii) searching in databases for grey literature. A network meta-analysis (NMA) was conducted, and the probability that each protocol is the "Best" was estimated. RESULTS: Nine RCTs were included, with a total of 1,693 participants. Due to the few events reported, it was not possible to conduct a NMA for adverse events, therefore it was conducted only for implant failures (IF). The protocol with the highest probability (32.5%) of being the "Best" one to prevent IF was the single dose of 3 g of amoxicillin administered 1 hr pre-operatively. Even if the single pre-operative dose of 2 g of amoxicillin is the most used, it achieved only a probability of 0.2% to be the "Best" one. CONCLUSIONS: Basing on the available RCTs, the use of antibiotic prophylaxis is protective against early implant failures. Whenever an antibiotic prophylaxis is needed, there is still insufficient evidence to confidently recommend a specific dosage. The use of post-operative courses does not seem however to be justified by the available literature. Prospero registration number: CRD42015029708.

The association between periodontitis and sleep duration.

AIM: Due to its potential to influence systemic inflammation and oxidative stress, and to predispose to bacterial infections, sleep duration could potentially be a risk factor for periodontitis. The aim of this cross-sectional study was to evaluate if there was in 2012 an association between periodontitis and sleep duration in a representative sample of the South Korean population. MATERIALS AND METHODS: A total of 5812 subjects representative of 39.4 million of adults were examined. Multivariate logistic regressions were applied controlling for age, gender, education, smoking status, alcoholism and consumption frequency of coffee, tea, chocolate and red wine. RESULTS: Compared to the group sleeping ≤5 h/day, the adjusted odds ratios for periodontitis prevalence defined as Community Periodontal Index (CPI) = 4 were OR = 2.46 (95% CI: 1.20-5.06) in the 6 h/day sleepers group, OR = 2.66 (95% CI: 1.35-5.25) in the 7 h/day sleepers group, OR = 2.29 (95% CI: 1.13-4.63) in the 8 h/day sleepers group and OR = 4.27 (95% CI: 1.83-9.97) in the ≥9 h/day sleepers group. The association has shown to be highlighted in middle-aged people, females, non-smokers, lower educated, with lower lead and higher cadmium blood levels and with higher carotene dietary intake ones and to be partially mediated by lipid profile alterations, diabetes, serum Vitamin D levels and WBC count. CONCLUSIONS: A novel, direct and independent association between sleep duration and the prevalence of periodontitis was found. However, it needs to be investigated how the factors influencing the sleep duration affect this association.

Laser-Treated Titanium Implants: An In Vivo Histomorphometric and Biomechanical Analysis.

PURPOSE: The aim of the present histological and biomechanical analysis was to compare, in vivo, the strength and quality of osseointegration between a laser-treated implant surface and a standard machined surface. MATERIAL AND METHODS: Customized titanium implants, having 2 different surfaces, were used. Implants were longitudinally split in the 2 surfaces: one side was laser treated and the opposite one had a machined surface. Eight implants were inserted in the iliac crest of 2 sheep: 4 with a split laser and machined surfaces, 2 with a completely laser-treated surface, and 2 with fully machined surfaces. The animals were killed 8 weeks after the placement of implants. The histomorphometric and biomechanical parameters calculated for each surface were the bone-implant contact (%BIC) and the reverse torque value (RTV) RESULTS:: The RTV of the laser-treated implants were about 3-fold higher than that of the machined implants. The histomorphometric results showed a significant difference of %BIC around 30% between the laser surfaces compared to the machined ones. CONCLUSIONS: The present study showed that laser surface treatment induces better osteointegration than machined surface. The laser-treated surface seems to be able to increase the osseointegration amount in respect to the machined implants.

Morphological Aspect and iNOS and Bax Expression Modification in Bone Tissue Around Dental Implants Positioned Using Piezoelectric Bone Surgery Versus Conventional Drill Technique.

BACKGROUND: The aim of this work is to evaluate differences occurring in bone tissue around dental implants positioned using piezoelectric or conventional drill technique. METHODS: Twenty-four implants were inserted bilaterally in the iliac crest of 6 sheep after site preparation through a piezoelectric instrument (Test) or after site preparation through conventional drill technique with rotary instruments (Control). Animals were randomly divided to be euthanized at 15 and 30 days post-intervention (p.i.); peri-implant bone samples were withdrawn and processed for histological analysis and immunohistochemical evaluation of iNOS and Bax expression. RESULTS: Active remodeling phenomena in both Test and Control samples are showed at 15 days p.i., while at 30 days p.i., the overall organization of the peri-implant bone resembles native bone tissue. Immunohistochemical evaluation reveals a statistically significant increase of both iNOS and Bax expression at 15 days p.i. compared to samples obtained 30 days p.i. and to native bone. At both healing times, a higher but not statistically significant iNOS and Bax expression is recorded in samples from Control compared to Test Group. CONCLUSION: Even if the insertion protocol does not seem to significantly interfere with the long-term healing process, implant site preparation through the piezoelectric bone surgery technique may allow a reduction of peri-implant bone tissue inflammation and support a more rapid bone tissue healing phase.

Insufficient irrigation induces peri-implant bone resorption: an in vivo histologic analysis in sheep.

OBJECTIVES: To measure in vivo impact of dense bone overheating on implant osseointegration and peri-implant bone resorption comparing different bur irrigation methods vs. no irrigation. MATERIALS AND METHODS: Twenty TI-bone implants were inserted in the inferior edge of mandibles of sheep. Different cooling procedures were used in each group: no irrigation (group A), only internal bur irrigation (group B), both internal and external irrigation (group C), and external irrigation (group D). The histomorphometric parameters calculated for each implant were as follows: %cortical bone-implant contact (%CBIC) and %cortical bone volume (%CBV). Friedman's test was applied to test the statistical differences. RESULTS: In group A, we found a huge resorption of cortical bone with %CBIC and %CBV values extremely low. Groups B and C showed mean %CBIC and %BV values higher than other groups The mean %CBV value was significantly different when comparing group B and group C vs. group A (P < 0.05). Significant differences in %CBIC were found also between group C and group A (P < 0.05). CONCLUSIONS: Thermal injury, due to insufficient irrigation, of hard bone caused massive resorption of the cortical bone and implant failure. Drilling procedures on hard bone need an adequate cooling supply because the bone matrix overheating may induce complete resorption of dense bone around implants. Internal-external irrigation and only internal irrigation showed to be more efficient than other types of cooling methods in preventing bone resorption around implants.

Effect of low-level laser therapy after extraction of impacted lower third molars.

The aim of this study is to evaluate the effectiveness of the low-level laser therapy (LLLT) in the control of pain, swelling, and trismus associated with surgical removal of impacted lower third molars. Thirty patients were randomized into two treatment groups, each with 15 patients-group test (LLLT) and a group control (no-LLLT)-and were told to avoid any analgesics 12 h before the procedure. In group test, the 980-nm diode-laser (G-Laser 25 Galbiati, Italy) was applied, using a 600-µm handpiece, intraorally (lingual and vestibular) at 1 cm from the involved area and extraoral at the insertion point of the masseter muscle immediately after surgery and at 24 h. The group control received only routine management. Parameters used for LLLT were: continuous mode, at 300 mW (0.3 W) for a total of 180 s (60 s × 3) (0.3 W × 180 s=54 J). Group test showed improvement in the interincisal opening and remarkable reduction of trismus, swelling and intensity of pain on the first and the seventh postoperative days. Although LLLT has been reported to prevent swelling and trismus following the removal of impacted third molars, some of these studies reported a positive laser effect while others did not. All references to the use of laser therapy in the postoperative management of third molar surgery employ different methodologies and, in some, explanations as to selection of their respective radiation parameters are not given. This study has demonstrated that LLLT, with these parameters, is useful for the reduction of postoperative discomfort after third-molar surgery.

Primary stability, insertion torque, and bone density of conical implants with internal hexagon: is there a relationship?

Between implants and peri-implant bone, there should be a minimum gap, without micromotions over a threshold, which could cause resorption and fibrosis. The higher the implant insertion torque, the higher will be the initial stability. The aim was to evaluate in vitro the correlation between micromotions and insertion torque of implants in bone of different densities. The test was performed on bovine bone of hard, medium, and soft density: 150 implants were used, 10 for each torque (20, 35, 45, 70, and 100 N/cm). Samples were fixed on a loading device. On each sample, we applied a 25-N horizontal force. Insertion torque and micromotions are statistically correlated. In soft bone with an insertion force of 20 and 35 N/cm, the micromotion resulted significantly over the risk threshold, which was not found with an insertion force of 45 and 70 N/cm and in hard and medium bones with any insertion torque. The increase in insertion torque reduces the amount of micromotions between implant and bone. Therefore, the immediate loading may be considered a valid therapeutic choice, even in low-density bone, as long as at least 45 N/cm of insertion torque is reached.

Primary stability, insertion torque and bone density of cylindric implant ad modum Branemark: is there a relationship? An in vitro study.

OBJECTIVES: Protocols of immediate loading have been reported in several studies. It has also been demonstrated that the cause of failure of immediate loaded implants is due to the micromotion on the bone-implant interface induced by immediate loading. There should be a minimum gap between the implant and the peri-implant bone, without micromotions occurring above a definite threshold risk as they induce bone resorption and fibrosis around the implant. Measurement of the torque necessary to insert an implant in the bone is a parameter for measuring initial stability. The higher the implant insertion torque, the higher the initial stability attained. The aim of this study was to evaluate in vitro the correlation between the micromotion of cylindric screw implants ad modum Branemark and the insertion torque in bone of different densities. MATERIAL AND METHODS: The test was carried out on 2 × 2 cm samples of fresh bovine bone of three different densities: hard (H), medium (M) and soft (S). One hundred and fifty hexa implants ad modum Branemark were used, 3.75 mm in diameter and 9 mm long. To screw in the implants, a customized manual key was used, controlled digitally to evaluate the peak insertion torques. Ten implants were prepared for each torque (20, 35, 45, 70 and 100 N/cm). The bone sample was then fixed on a loading device, which allowed evaluating the micromotion. On each sample, we applied a 25 N horizontal force. RESULTS: The results indicate that the peak insertion torque and the implant micromotion are statistically correlated, and statistically significant differences in H and M bone were found compared with S bone. In S bone, we noted a micromotion significantly higher than the risk threshold, and it was not possible to reach peak insertion torque above 35 N/cm. In H and M bone, the micromotion is below the threshold of all insertion torques. CONCLUSIONS: Increasing the peak insertion torque, we can reduce the extent of the micromotion between the implant and the bone when submitted to lateral forces in vitro. In soft bone, the micromotion was always high; hence, immediate loading of implants in low-density bone should be evaluated with care.

New laser-treated implant surfaces: a histologic and histomorphometric pilot study in rabbits.

PURPOSE: The purpose of this study was to confirm the validity of laser treated implant surfaces, with regard to high superficial purity preservation and to extremely regular and uniform roughness surfaces. METHODS: In this in vivo study, seven different laser treated implant surfaces were analyzed. A diode-pumped solid state source laser, in a Q-Switch output mode, was used at various wavelengths, which were chosen to generate surface irregularities of varying diameter, depth and pitch. Twenty one implants were placed in 11 New Zealand rabbits. Eight weeks after surgery, implants were harvested for histometric analysis: total, threads and body bone-to-implant, and bone-to-implant contacts were measured. The morphologic analysis of the surface was carried out using a Scanning Electron Microscope. RESULTS: Average bone-implant contact values were approximately 50% for all tested surfaces. Both total and threads values, within the same processing pattern group, had a high variance. Bone-implant contact thread and body variances were different, so that is possible that laser beam angle is able to modify the superficial roughness and thus the histological response. CONCLUSIONS: Implants provided with pores of 20 and 25 µm achieved more than satisfactory bone-implant contact partial peaks. Further statistically significant experiments are needed in order to study, in depth, these surfaces.

Implant micromotion is related to peak insertion torque and bone density.

OBJECTIVES: Measuring peak insertion torque in relation to different bone densities, the present study seeks to determine whether micromotion at the interface is related to primary stability achieved by increasing insertion torque. MATERIAL AND METHODS: A total of 120 Ti-Bone implants were placed in fresh bovine bone samples representing three density categories: hard, normal and soft (HNS). Five groups of peak insertion torque (20, 35, 45, 70 and 100 N/cm) were evaluated in the three bone density categories noted. Customized electronic equipment connected to a PC was used to register the peak and other insertion torque data. A loading device, consisting of a digital force gauge and a digital micrometer, was used to measure the micromovements of the implant during the application of 20, 25 and 30 N lateral forces. The data were analyzed for statistical significance by ANOVA and Spearman's rank correlation coefficient tests. RESULTS: A statistically significant difference between implant micromobility placed with different levels of torque and in different bone densities was demonstrated by ANOVA. Spearman's rank correlation coefficient showed a high dependency between the peak insertion torque and the observed micromovement. Particularly, in soft bone, it was not possible to achieve more than 35 N/cm of peak insertion torque. CONCLUSIONS: Results showed that increasing the peak insertion torque reduces the level of implant micromotion. In addition, micromotion in soft bone was found to be consistently high, which could lead to the failure of osseointegration. Thus, immediate functional loading of implants in soft bone should be considered with caution.

Clinical, microbiologic, and biochemical effects of subgingival administration of a Xanthan-based chlorhexidine gel in the treatment of periodontitis: a randomized multicenter trial.

BACKGROUND: The use of locally delivered antibacterials containing chlorhexidine (CHX) was proposed to improve the effectiveness of non-surgical periodontal treatment. The present multicenter randomized study investigated the effects of a xanthan-based chlorhexidine (Xan-CHX) gel used as an adjunct to scaling and root planing (SRP) in the treatment of chronic periodontitis. METHODS: Ninety-eight systemically healthy subjects with moderate to advanced periodontitis were recruited in four centers (59 females and 39 males; aged 24 to 58 years). For each subject, two experimental sites located in two symmetric quadrants were chosen with probing depths (PD) >or=5 mm and positive for bleeding on probing (BOP). These two sites were randomized at the split-mouth level with one receiving a single SRP treatment and the other receiving a single SRP + Xan-CHX gel treatment. Supragingival plaque, modified gingival index, PD, clinical attachment level (CAL), and BOP were evaluated at baseline (prior to any treatment) and after 3 and 6 months. At the same times, subgingival microbiologic samples and gingival crevicular fluid (GCF) were collected for the analysis of total bacterial counts (TBCs), including the identification of eight putative periodontopathogens, and alkaline phosphatase (ALP) activity, respectively. RESULTS: The Xan-CHX treatment group showed greater improvements compared to the SRP group for PD and CAL at 3 and 6 months (P <0.001). The differences in PD reduction between the treatments were 0.87 and 0.83 mm at 3 and 6 months, respectively (P <0.001); for CAL, these were 0.94 and 0.90 mm, respectively (P <0.001). Similar behavior was seen when the subgroup of pockets >or=7 mm was considered. The percentage of sites positive for BOP was similar between the treatments at each time point. For the comparisons between the treatment groups, no differences were seen in the TBCs and GCF ALP activity at baseline and 6 months; in contrast, slightly, but significantly, lower scores were recorded for the Xan-CHX treatment group at 3 months (P = 0.018 and P = 0.045, respectively). Moreover, greater reductions in the percentages of sites positive for the eight putative periodontopathic bacteria were generally seen for the Xan-CHX treatment group compared to SRP alone. CONCLUSIONS: The adjunctive use of Xan-CHX gel promoted greater PD reductions and CAL gains compared to SRP alone. These results were concomitant with better microbiologic and biochemical outcomes when Xan-CHX gel use was added to SRP, particularly up to 3 months after treatment.

A Human Clinical and Histomorphometrical Study on Different Resorbable and Non-Resorbable Bone Substitutes Used in Post-Extractive Sites. Preliminary Results.

BACKGROUND: The healing of sockets following teeth extraction results in a marked reduction of the height and width of the ridge. This in vivo study aims to assess and compare the efficacy of calcium sulphate (CS) and sintered nano-hydroxyapatite (NHA) in postextraction sockets. MATERIALS AND METHODS: 10 subjects were enrolled for single or multiple tooth extraction and implant placement. Each site was randomly assigned to one of four groups and filled with CS, NHA, a combination of CS and NHA, or left to normal healing. After five months tissue samples were harvested from the extraction sites and prepared for histological investigations. RESULTS: Histomorphometric analysis showed that the average percentages of vital bone was 13.56% ± 13.08% for CS, 17.84% ± 7.32% for NHA, 58.72% ± 8.77% for CS + NHA%, and 80.68% ± 21.8% for the controls; for the connective tissue the results were 33.25% ± 35.75% for CS, 55.88% ± 21.86% for NHA, 17.34% ± 8.51% for CS + NHA, and 22.62% ± 0.52% for the controls; for residual biomaterial the results were 0.56% ± 0.52% for CS group, 21.97% ± 0.79% for NHA, and 47.54% ± 20.13% for CS + NHA. Conclusions: Both biomaterials led to bone tissue formation after five months of healing. The combination of the biomaterials presented a better behavior when compared to the individual application.

Surgical treatment of periodontal intrabony defects with calcium sulfate implant and barrier versus collagen barrier or open flap debridement alone: a 12-month randomized controlled clinical trial.

BACKGROUND: This randomized controlled clinical trial was designed to compare the clinical outcomes of guided tissue regeneration with calcium sulfate graft and membrane (CS) versus guided tissue regeneration with collagen membrane (CM) or open flap debridement (OFD) only in terms of clinical attachment gain in periodontal intrabony defects. METHODS: Fifty-one systemically healthy, non-smoking subjects affected by moderate to severe chronic periodontitis were recruited. The subjects had one deep intrabony defect with a probing depth (PD) > or =6 mm and were randomly divided into three equal groups (17 subjects per group). Subjects were surgically treated with OFD (OFD group), OFD with CS (CS group), or OFD and CM (CM group). One year after surgical treatment, a complete clinical examination and a surgical reentry were performed. The pre- and post-therapy clinical parameters, including PD, clinical attachment level (CAL), gingival recession (GR), and intrasurgical parameters (defect bone level [DBL]), were compared. RESULTS: After 1 year, the clinical and intrasurgical parameters showed statistically significant changes from baseline within each group for all of the evaluated parameters (PD and CAL, P <0.001; GR and DBL, P <0.05). Differences (PD, CAL, and DBL, P <0.001; GR, P <0.05) were also seen across the three groups. The CM and CS groups had significantly smaller PD, CAL, and DBL values than subjects treated with only OFD. Groups treated with regenerative techniques had a significantly greater PD reduction and CAL and DBL gain compared to the OFD group. No significant differences were seen between CM and CS. Conversely, the CM group showed a significantly greater GR increase compared to OFD and CS. CONCLUSIONS: Both regenerative treatments produced additional clinical benefits over OFD alone. Moreover, the use of CS may minimize post-surgical recession.

The zirconia-reinforced lithium silicate ceramic: lights and shadows of a new material.

This study aims to investigate the mechanical properties, composition and surface preparation for adhesive bonding of the recently introduced zirconia-reinforced lithium silicate (ZLS) glass-ceramic. One single block of ZLS was used to prepare the specimens (n=14). The fracture toughness (Ft) and the Vickers hardness (HV) were measured on specimens partially crystallized (PCs) (n=4) and fully crystallized (FCs) at 840°C for 8 min (n=4). The surface treatment was done using hydrofluoric-acid gel (HF) at different concentrations and times of action on FCs specimens (n=4). SEM-EDX was used to test elemental composition and crystalline phases (n=2). The new ZLS glass-ceramic showed significantly higher values of HV and Ft for FCs, PCs showed a brittle behavior. The surface etching should be made using HF at 4.9% for 20 s.

Autogenous periosteal barrier membranes and bone grafts in the treatment of periodontal intrabony defects of single-rooted teeth: a 12-month reentry randomized controlled clinical trial.

BACKGROUND: This randomized clinical trial compares the outcomes of combination treatment by autogenous periosteal membranes and bone graft versus guided tissue regeneration (GTR) with collagen membranes or open-flap debridement (OFD) only in the treatment of intraosseous defects. METHODS: Forty-two patients affected by moderate to severe chronic periodontitis were enrolled. Each patient had one deep intrabony defect (≥6 mm). They were randomly assigned into three groups: patients treated with 1) an OFD procedure alone (OFD group); 2) a GTR procedure with collagen membranes (GTR group); and 3) a combined treatment procedure by autogenous periosteal membranes and autogenous bone chips (aCPRT group). Clinical and intrasurgical examinations including probing depth (PD), clinical attachment level (CAL), gingival recession (GR), and defect bone level (DBL) were performed at baseline and after 1 year. RESULTS: After 1 year, all of the evaluated clinical parameters showed statistically significant changes from baseline within each group (P <0.01). The GTR and aCPRT groups had significantly greater PD reductions (5.2 and 4.4 mm, respectively) and CAL (3.2 and 3.9 mm) and DBL gains (2.4 and 3.1 mm) compared to the OFD group (PD, 2.9 mm; CAL, 1.6 mm; DBL, 1.5 mm); moreover, the aCPRT group showed a significantly smaller GR increase (0.5 mm) and a greater DBL gain (3.1 mm) compared to the GTR group (2 and 2.4 mm, respectively; P <0.05). CONCLUSIONS: Both the GTR and aCPRT treatments produce additional clinical benefits over OFD alone. Moreover, the aCPRT technique can minimize post-surgical GR and produce better defect bone-level improvement.

Expression of hMSH2 and hMLH1 proteins of the human DNA mismatch repair system in salivary gland tumors.

BACKGROUND: The human DNA mismatch repair (hMMR) system plays an important role in reducing mutation and maintaining genomic stability. The MMR system in human cells is composed of at least six genes (hMSH2, hMLH1, hMSH3, hPMS1, hPMS2 and GTBP/hMSH6). In particular, hMSH2 and hMLH1 are expressed in cells undergoing rapid renewal; their reduced expression has been reported in several tumors. METHODS: We examined the expression of hMSH2 and hMLH1 by immunohistochemistry in tumor specimens from 43 patients with primary tumors. RESULTS: All carcinomas (n = 20) expressed these proteins. In addition, when compared to pleomorphic adenomas, malignant tumors contained significantly (P < 0.01) higher proportions of hMSH2 (56.1 +/- 31.5 vs. 31.1 +/- 22.6) and hMLH1 (27.9 +/- 26.0 vs. 14.0 +/- 12.6) positive cells. Warthin's tumors showed no specific nuclear staining of tumor cells for both hMSH2 and hMLH1. CONCLUSIONS: These data suggest a minor, if any, role for a defect in the hMMR system in the pathogenesis of malignant salivary gland tumors.