Giorgio Perfetti

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 Spearmans 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. Spearmans 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.

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.

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.

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). Friedmans 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.

N-3 polyunsaturated fatty acid effect in periodontal disease: state of art and possible mechanisms involved.

Anti-inflammatory properties have been widely reported for n-3 polyunsaturated fatty acids (PUFAs) and some studies have been focalized on their possible role in the modulation of gingivitis and alveolar bone resorption in periodontal disease (PD). Increased formation of arachidonic acid-derived inflammatory eicosanoids and augmented oxidative stress are two molecular mechanisms pathogenetically involved in the progression of PD and known to be inhibited by n-3 PUFAs in PD setting. The present review will focus also on other molecular pathways and factors known to be altered in the development of PD and known to be subject to n-3 PUFA modulation in other pathological settings different from PD. Overall, the available findings strongly encourage further experimental studies on animals subject to experimental PD and treated with n-3 PUFAs, long term n-3 PUFA intervention studies on PD patients and molecular studies to identify additional potential molecular routes of n-3 PUFA action in PD.

Evaluation of Neridronate on the Osseointegration Process of Endeous Titanium Implants in Animal Models

Bisphosphonates are compounds that inhibit bone reabsorption mediated by osteoclasts. The use of bisphosphonates in oral implantology is still in the experimental stage. The aim of this study is to evaluate the efficacy of an aminobisphosphonate to increase the ability of the drug to act on the implant and bone surfaces in the development of the osseointegration in sheep. Forty SLA titanium implants were used on sheep iliac crests. Neridronate added to connective gel (test 1) or to physiological solution (test 2) was used in order to increase the bone and implant adhesiveness. Physiological solution (control 1) or connective gel (control 2) alone was given to the control groups. A topical administration of Neridronate was made on the implant surface and in the implant site. Four Bergamasca sheep were used and were sacrificed by intravenous injection of 10 cc Tanax after 8 weeks from implantation. Histologic and histomorphometric analyses were carried out. The results did not show significant differences between the test group and control group. Our data are different from other similar studies obtaining statistically significant differences. These differences could depend on the procedure of application of the drug on the implant. This study demonstrates the poor efficacy of neridronate applied topically to the implant and implant site during surgery. Further studies using different fixation techniques of the drug may be necessary to confirm the present data.

Primary Stability, Insertion Torque, and Bone Density of Conical Implants With Internal Hexagon: Is There a Relationship?

AbstractBetween 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.

Potential applications of biphosphonates in dental surgical implants.

Biphosphonates are largely used for their unquestionable properties of inhibiting bone resorption by osteoclast in the treatment of various osteometabolic illnesses such as osteoporosis, multiple myeloma, tumors which metastasize to the bone and malignant hypercalcemia. In this literature review the physico-chemical properties, biologic activities and the mechanisms of action of biphosphonates are described. The use of these drugs is discussed, analyzing the quantity of results which have emerged through in vitro and in vivo experiments on animal models. In this study the efficiency of these drugs is demonstrated in contrasting the osteolitic processes of the alveolar bone, in promoting the neoformation and in bettering the quality of bone implants. However, it is important to draw attention to a worrying correlation which has emerged during the last 3–4 years, between osteonecrosis of the jaw (ONJ) and the systemic administration of aminobiphosphonates. This collateral effect did not emerge following the use of non-aminobiphosphonates. The aim of this revie w is to identify the guidelines for the use of biphosphonates in oral implant surgery.

In vitro evaluation of the efficacy of a new laser surface implant: cellular adhesion and alkaline phosphatase production tests.

Bone tissue reacts in different ways to implant surfaces with different patterns. The aim of this study is to understand which laser generated surface pattern produces the best cell adhesion in vitro, evaluating both the activity of the alkaline phosphatase and the cells adhering to titanium samples. Tests were carried out on titanium samples with sandblasted surfaces with laser-produced holes with diameters of 5, 10, and 20 μm, and on sandblasted titanium cylinders without holes as controls. The samples were inserted into culture medium containing SaOS-2 cells for 3, 7 and 10 days. The results showed that at days 3 and 7 the laser surfaces stimulated a higher production of alkaline phosphatase (ALP) compared to the data from the control group. At day 10 there were no significant differences between the test group and the control group.