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To evaluate if a different morphology of the implant-abutment connection (internal vs. external hexagon) is able to condition the behaviour of hard and soft peri-implant tissues.Twenty patients with significantly unfavourable prognoses for their residual maxillary or mandibular dentitions were selected and rehabilitated with immediately loaded fixed full-arch rehabilitations in two different centres. Four to six implants with identical macro- and micro-topography were inserted in each arch: external hexagon implants (EHC) in one randomly selected side of the dental arch and internal hexagon implants (IHC) in the other side. Primary outcome measures were the success rates of the implants and prostheses. Any technical and biological complication was recorded. Secondary outcome measures were: peri-implant marginal bone level (MBL) changes, Plaque Index (PI), probing depth (PD) and bleeding on probing (BoP), evaluated at implant insertion and at 3, 6 and 12 months post-loading.Forty-three EHC and 40 IHC implants were inserted in 20 patients. No patients dropped out. Two implants failed; one IHC after 3 months and one EHC after 6 months in two different patients (difference IHC vs. EHC at patient level: 0.06%; 95% CI: -1.9 to 2.1; P = 0.99). No prosthesis failed. No biological complications were identified and three loose prosthetic abutment screws were identified in three different patients (two EHC and one IHC); difference at patient level IHC vs. EHC: 2.1% (95% CI: -0.8 to 5; P = 0.43). Overall marginal bone loss was not significantly different between the two treatment groups (EHC vs. IHC) at any time point. The mean difference of bone levels between EHC and IHC was 0.25 mm (95% CI: -0.18 to 0.69) at implant placement. Mean difference between IHC and EHC was -0.01 mm (95% CI: -0.34 to 0.36) at 3 months, 0.13 mm (95% CI: -0.48 to 0.22) at 6 months and 0.11 mm (95% CI: -0.45 to 0.25) at 12 months. All the implants showed good periodontal health at the 1-year-in-function visit, with no statistically significant differences between groups. At 12 months mean (± standard deviation) PI was 2 (± 1.5) for the EHC and 1.85 (± 1.58) for the IHC group (P = 0.57) with a mean difference between the two groups of 0.15 (95% CI: -0.56 to 0.85). Mean PD was 2.23 mm (± 0.52) for the EHC and 2.10 mm (± 0.39) for the IHC group (P = 0.39), with a mean difference between the two groups of 0.12 mm (95% CI: -0.08 to 0.33). At 12 months 41.4% of EHC and 43.6% of IHC implants presented no BoP (mean difference: -2.2%, 95% CI: -24.0 to 19.3; P = 0.51). No significant effect of centres over all outcomes was identified (P = 0.71 for MBL, P = 0.14 for PI, P = 0.14 for PD and P = 0.20 for BoP).On the basis of the present trial the two types of implant connections were clinically reliable. After 12 months in function, both implants provided good clinical outcomes, without statistically significant differences between the two groups.

The present study was aimed to evaluate the effect of introducing administration of the proteolytic enzyme serratiopeptidase in the combined mechanical-antibiotic treatment of periimplantitis (PI). Two randomized groups of 64 adults with a diagnosis of PI were studied over a 6-month period. All patients were treated with a combined mechanical and antibiotic protocol for 15 days. The experimental group (EG) was administered antibiotic and serratiopeptidase, while the control group was administered antibiotic alone. To evaluate the effects of the two treatment protocols, clinical and radiographic indices, the concentration of IL-lβ, IL-6 and TNF-α in the gingival crevicular fluid, the amount of total bacteria] DNA and the presence of specific bacteria were assessed at baseline and at 6 months from treatment. Success rates of combined treatments at 6 months were 96.9% and 78.1% for the EG and CG respectively ( P≤0.01). Implants of the EG showed greater enhancement of clinical, microbiological and inflammatory parameters as compared to those of the CG. Microbiological analyses showed that resistance to combined therapy was constantly associated with the isolation of bacterial species that are not common periodontal pathogens (mainly S.aureus and P.aeruginosa). The data demonstrate that the addition of serratiopeptidase to combined mechanical-antibiotic treatment protocols of periimplantitis significantly improves outcomes and suggest that serratiopeptidase acts at different levels during the healing process.

This in vitro study investigated the depth of cure of a microhybrid composite resin when cured with reduced times of exposure to three commercially available curing lights. Different sample thicknesses (1, 2, and 3 mm) were light cured in high intensity polymerization mode (2,400 mW/cm² for 5, 10, 15, and 20 seconds; 1,100 mW/cm² for 10, 20, 30, and 40 seconds; and 1,100 mW/cm² for 10, 20, 30, and 40 seconds, respectively). The degree of conversion (%) at the bottom of each sample was measured by Attenuated Total Reflection Fourier Transform Infrared (ATR F-TIR) analysis after each polymerization step. Data were analyzed by ANOVA for repeated measures, showing the degree of conversion was not influenced by the curing light employed (P = .622) but was significantly influenced by the thickness of composite resin (P.05). Variations in the degree of conversion vs the shorter irradiation time permitted (T1) were not significant among different lamps but were significant among different thicknesses. The depth of cure of microhybrid composite resin appears not to be influenced by the curing light employed. Increased irradiation time significantly increases the degree of conversion. Thickness strongly influences depth of cure.

The aim of this study was to compare survival rates and radiographic outcomes of immediate and delayed implant loading in edentulous maxillae.Forty-nine patients in need of maxillary full-arch treatment were randomized into two groups: test group (n = 34) treated following the Columbus Bridge Protocol with 4 to 6 implants loaded within 24 hours and a control group (n = 15) treated following the ad modum Branemark protocol with 6 to 9 implants loaded a mean 8.75 months after surgery. Two hundred sixty implants (test: n = 163, control: n = 97) were placed, and subjects were treated with screw-retained full-arch prostheses. Bone levels were measured at baseline and at 1, 2, and 3 years and analyzed using repeated-measures analysis of variance.All patients appeared at all scheduled recall visits. No differences in cumulative survival rates were found between groups at 36 months. Ten implants (6.1%) failed in the test group; four (4.1%) failed in the control group. At 36 months, no prosthetic failures were detected. Significantly less bone loss was found in the test group at all time intervals (P.001). The average bone level from the implant-abutment connection was 1.3 mm in the test group and 1.9 mm in the control group at 12 months, 1.5 mm and 2.2 mm at 24 months, and 1.6 mm and 2.3 mm at 36 months, respectively.In the edentulous maxilla, the Columbus Bridge Protocol involving immediate loading of implants placed in both healed and fresh extraction sites exhibited equivalent implant survival and less marginal bone loss at 3 years compared to the conventional two-stage delayed loading protocol. Int J Prosthodont 2011;24:294-302.