Impact of surface contamination of implants with saliva during placement in augmented bone defects in sheep calvaria

Impact of salivary contamination during implant placement with different surface characteristics in native and augmented bone: An in vivo study in sheep calvaria model

OBJECTIVES

The aim of this study was to evaluate whether salivary contamination during placement of implants with different surface characteristics affects osseointegration in native and in augmented bone areas.

MATERIALS AND METHODS

Forty eight implants with machined surface (MS) and 48 implants with moderately rough surface (RS) were tested in the calvaria of 12 sheep. At the first surgery, 64 bony critical defects were randomly created and were subsequently augmented with two materials (autogenous or bovine bone). After 5 weeks of graft healing, 8 implants were placed per sheep, in native bone and in the centre of the augmented defects. Forty eight implants were soaked with saliva before placement (contaminated group [CG]), while 48 implants were not (non-contaminated group [NCG]). Five weeks after implant placement, bone-to-implant contact (BIC) and bone material area fraction occupancy (BMAFO) were calculated histomorphometrically.

RESULTS

Saliva contamination showed a significant negative effect (p = .000) on BIC, especially in augmented areas. RS showed significant positive effect on BIC, compared to MS (p = .000), while there were no significant differences for different bone conditions (p = .103). For BMAFO, the contamination showed a significantly negative affect (p = .000), while there were no significant differences for surface characteristics (p = .322) and for bone condition (p = .538).

CONCLUSION

Saliva contamination during dental implant placement has a negative effect on osseointegration in augmented areas. Moderately rough surface has a possible advantage in the aspect of initial bone to implant contact. However, it seems to be advisable to avoid saliva contamination especially for implants placed in augmented bone areas.

Preoperative administration of amoxicillin is not recommended in healthy patients undergoing implant surgery

Design A multicentre, prospective, randomised, placebo-controlled, double-blinded clinical trial reported the early implant failure and postoperative infections of healthy or relatively healthy patients receiving 2 grams of amoxicillin one hour preoperatively from their scheduled dental implant placement. The registration of the study protocol in EudraCT and Clinical Trials.gov (#NCT03412305) followed the ethical principles of the Declaration of Helsinki and the CONSORT guidelines for clinical trials.Case selection Several trial drugs expired before recruiting the intended 1,000 patients calculated based on previous trials reporting 2% and 5% early implant loss, with and without antibiotic prophylaxis. Thus, the study cohort (age >18 years, not planned for immediate loading, not requiring substantial bone augmentation, with an absence of severe diseases or immunosuppression or immunodeficiency) received 757 implants in total between November 2014 and April 2018, consisting of the prophylactic antibiotic therapy group (patients n = 235) and the placebo group (patients n = 235), with a fair sex distribution and a mean age of 57.4 ± 13.9 years. A computer-generated list of random numbers assisted the randomisation (test or control group) with a block-size six. For the clinical procedures, bone augmentation was limited to autogenous bone chips and bone debris. One- and two-stage surgery protocols were used in maxillary or mandibular single or multiple dental implants. The utilised implant systems were Straumann SLA (Straumann Implants, Switzerland), Astra Tech Dental Implant Systems (Dentsply Sirona, Sweden), Nobel Biocare (Sweden) and Southern Implants (Ltd, South Africa). Chlorhexidine 0.2% was prescribed preoperatively and/or postoperatively. Implant failure was the main measured outcome, whereas postoperative infections and adverse events were the secondary outcomes postoperatively assessed at 7-14-day (first follow-up) and 3-6-month (second follow-up) intervals.Data analysis The sample size calculation (type one error: 0.05; power: 80%) estimated 500 patients in each group. Proportional differences and relative risk (RR) with a 95% confidence interval (CI) were calculated. Implant failure was the dependent variable for the multiple logistic regression (MLR) model examining the indicator variables smoking (yes or no), and age (<50 years; 50-64; and ≥65), as well as the independent variables bone augmentation (yes or no), number of implants (1, 2-3 and ≥4), and treatment group (antibiotic prophylaxis or placebo). P-values <0.05 or 95% CIs for ratios not including one were deemed statistically significant. The analyses were carried out using statistical software for data science (STATA).Results Overall, six (2.5%) and seven patients (3.0%) from the amoxicillin and placebo groups had implant failures, respectively. Thus, the intergroup difference was not significant (RR: 0.85; 95% CI: 0.29-2.48, p = 0.75). Absolute risk reduction was 0.46%, with a number needed to treat (NNT) of 219. In other words, one in every 219 patients will benefit from receiving prophylactic antibiotics. In addition, no variable was associated with implant failure. Two (0.8%) and five patients (2.1%) from the amoxicillin and placebo groups, respectively, had postoperative infections at the first follow-up interval. Thus, the intergroup difference was not significant (RR: 0.29; 95% CI: 0.08-2.01, p = 0.25). Five (2.1%) and seven patients (3.0%) from the amoxicillin and placebo groups, respectively, had postoperative infections at the second follow-up interval. Thus, the intergroup difference was not significant (RR: 0.70; 95% CI: 0.23-2.18, p = 0.54). No adverse events were reported.Conclusion Prophylactic antibiotic treatment for dental implant surgery to prevent implant loss may not be appropriate. Each dose must be prescribed based on evidence-based guidelines to avoid overuse and misuse of antibiotics promoting resistant bacteria.

Effect of antibiotic prophylaxis in dental implant surgery: A multicenter placebo-controlled double-blinded randomized clinical trial

BACKGROUND

The growing resistance of bacteria to antimicrobial medicines is a global issue and a direct threat to human health. Despite this, antibiotic prophylaxis is often still routinely used in dental implant surgery to prevent bacterial infection and early implant failure, despite unclear benefits. There is a lack of sufficient evidence to formulate clear clinical guidelines and therefore there is a need for well-designed, large-scale randomized controlled trials to determine the effect of antibiotic prophylaxis.

PURPOSE

To compare the effect of a presurgical antibiotic regimen with an identical placebo regimen in healthy or relatively healthy patients receiving dental implants.

MATERIALS AND METHODS

The 474 patients participating in the study were recruited from seven clinics in southern Sweden. We randomized the patients into a test and a placebo group; the study was conducted double-blinded. Preoperatively, the test group received 2 g of amoxicillin and the control group, identical placebo tablets. The primary outcome was implant failure; secondary outcomes were postoperative infections and adverse events. Patients were evaluated at two follow-ups: at 7-14 days and at 3-6 months.

RESULTS

Postoperative evaluations of the antibiotic (n = 238) and the placebo (n = 235) groups noted implant failures (antibiotic group: six patients, 2.5% and placebo group: seven patients, 3.0%) and postoperative infections (antibiotic group: two patients, 0.8% and placebo group: five patients, 2.1%). No patient reported any adverse events. Between-group differences in implant failures and postoperative infections were nonsignificant.

CONCLUSION

Antibiotic prophylaxis in conjunction with implant placement is likely of small benefit and should thus be avoided in most cases, especially given the unabated growth in antibiotic-resistant bacteria.

CLINICAL TRIAL REGISTRATION NUMBER

NCT03412305.

Influence of saliva interaction on surface properties manufactured for rapid osseointegration in dental implants

Surface treatments are designed to promote modified implant surfaces with positive interactions with the surrounding living tissues. However, the inadvertent early contact of these surfaces with oral fluids during surgery may lead to undesired conditions affecting osseointegration. This study aimed to investigate the possible alterations in the physico-chemical properties of modified-surfaces caused by early saliva exposure. Titanium (Ti) surfaces were exposed to three different samples of human saliva and later analyzed for protein adhesion, physico-chemical surface alterations, and osteogenic cell-viability. The results indicated that surface roughness was the most significant factor influencing saliva protein adsorption; moreover, hydrophilic surfaces had critically lost their characteristics after contact with saliva. Decreased cell viability was observed in cultures after contact with saliva. Early contact with saliva might negatively influence modified surface properties and local cell viability. Careful surgical insertion of implants with hydrophilic surfaces is recommended, particularly in sites where saliva interaction is prone to occur.

Impact of salivary contamination during placement of implants with simultaneous bony augmentation in iliac bone in sheep

Our aim was to investigate the possible impact of contamination with saliva on osseointegration during placement of implants with simultaneous bone augmentation. Six hemispheric shape bone defects (8mm in diameter×4mm deep) were prepared in each iliac bone of six sheep. A dental implant (2.9mm in diameter×10mm long) was placed in the centre of each defect, and then pairs of defects were filled with one of the following bone augmentation materials: autogenous bone, autogenous bone plus bovine bone, or resorbable biphasic ceramic bone substitute. One site in each augmentation group was impregnated with saliva (contaminated group), while the other was not (non-contaminated group). Bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) within implant threads were measured after a healing period of five weeks, both in respect of the implant inserted in the augmented bone and in that inserted in the residual bone. Overall results showed that there was a significant difference between the contaminated and non-contaminated group for BIC in the augmented implant (p=0.028), while there were no significant differences in the implant in residual bone (p=0.722). For BAFO, there were no significant differences between the contaminated and non-contaminated groups among the different augmentation materials. The results showed that contamination with saliva during placement of an implant with simultaneous bone augmentation had a serious deleterious effect on osseointegration of the aspect of the implant within the augmented defect. Contamination with saliva during placement of an implant with simultaneous bone augmentation should therefore be avoided.