A 3-year longitudinal prospective study assessing microbial profile and clinical outcomes of single-unit cement-retained implant restorations: Zirconia versus titanium abutments.

PURPOSE: The aim of this study was to assess the microbiological and clinical outcomes of implant-supported restorations on zirconia or titanium abutments after 3 years in function. MATERIALS AND METHODS: Twenty two-part dental implants were placed in 20 healthy individuals in need of single-tooth replacement. Ceramic-based reconstructions were cemented in either zirconia or titanium abutments. Clinical, radiographic, and microbiological outcomes were examined at implant loading and then yearly up to 3 years post-loading. RESULTS: Cumulative survival/success implant rates were 95% after 3 years. Mean total marginal bone loss was 0.76 ± 0.21 mm for zirconia and 0.99 ± 0.41 mm for titanium, with no significant differences (P > .05). Overall, titanium and zirconia abutments presented similar values of probing depth, gingival recession, and bleeding on probing over time (P < .05). Microbial profile of implants restored with titanium or zirconia is quite similar to that found in the remaining teeth. CONCLUSIONS: Zirconia and titanium presented different microbial profile and genome counts. Clinical findings for both zirconia and titanium abutments were similar and consistent with a healthy condition, reflecting a high survival rate and low bone loss. Microbiota did not impact the clinical outcomes after 3 years of function.

A Qualitative Study on Patients' Perceptions of Two Types of Attachments for Implant Overdentures.

The aim of this qualitative study was to gain a deeper understanding of patient perceptions of wearing implant-retained overdentures with ball-shaped or cylindrical attachment systems. Twenty-two wearers of implant-supported overdentures participated in this qualitative study based on a randomized crossover clinical trial that aimed to compare a cylindrical attachment and a ball attachment. In phase I of the study, group A experienced ball attachments (n = 11) and group B Locator attachments (n = 11) for 1 year. Afterward, in phase II, the attachments were changed; group A received Locator attachments and group B received ball attachments. One week after the attachment's replacement, semistructured individual interviews were conducted. All interviews were audiotaped and transcribed. The analysis was guided by thematic content analysis. Most of the patients from both groups preferred the attachment they received in phase II, regardless the type. A major theme raised by the participants to justify their preference between the attachment types was prosthesis retention/stability, sometimes considered as a positive and other times as a negative factor. Other themes were also explored: oral function, pain, hygiene, previous experiences, confidence on the dentist's work, and esthetic. Aspects related to the retention/stability of the overdentures are the main concerns associated with the perceptions of most patients treated with implant overdentures regardless of the type of attachment. Adequate retention level should be identified and adjusted on an individual basis and maintained overtime as possible. Therefore, follow-up appointments should be planned for readjustment of the attachment's retention. Overretention should be avoided.

Identification of oral bacteria on titanium implant surfaces by 16S rDNA sequencing.

OBJECTIVE: To characterize the profile of microbial communities colonizing titanium implants with different surface treatments after exposure to the oral environment at the genus or higher taxonomic level. MATERIAL AND METHODS: Sixteen titanium disks, machined or sandblasted large-grit and acid-etched (SLA), were mounted on removable intraoral splints worn by four patients. After 24 h of intraoral exposure, biofilm samples were collected from disks and supra/subgingival teeth areas. The 16S rDNA genes from each sample were amplified, sequenced with the Miseq Illumina instrument and analyzed. RESULTS: A total of 29 genera and seven more inclusive taxa, representing the phyla Firmicutes, Proteobacteria, Fusobacteria, Bacteroidetes, Actinobacteria and candidate division TM7 were identified in both titanium surfaces and teeth. No differences were found in relation to the operational taxonomic units (OTUs) and microbial diversity, assessed by Chao 1 and Shannon indices, when comparing SLA and machined titanium surfaces. CONCLUSIONS: Machined and SLA surfaces are colonized by similar numbers of prokaryotic OTUs after 24 h of exposure to the oral environment. Higher complexity of the titanium surface topography in the initial phase of biofilm maturation does not seem to significantly influence the colonizing microbiota.

Reduction of salivary S. aureus and mutans group streptococci by a preprocedural chlorhexidine rinse and maximal inhibitory dilutions of chlorhexidine and cetylpyridinium.

OBJECTIVES: Staphylococcus aureus and mutans group streptococci can cause, among many other diseases, infective endocarditis and postoperative infections. The reduction of the number of these microorganisms in the oral cavity prior to surgical procedures has been related to a decreased incidence of such occurrences. The aim of this study was to evaluate the effect of a single preprocedural rinse with 0.12% chlorhexidine solution (Periogard) on the salivary counts of S aureus and mutans group streptococci and determine maximal inhibitory dilutions (MID) of this and 0.05% cetylpyridinium chloride solution (Cepacol). METHOD AND MATERIALS: Saliva was collected from 60 patients before and after 30-second mouthrinses with chlorhexidine and cultured in appropriate media. The number of microorganisms was calculated based on the colony-forming units (CFUs). For the in vitro MID determination, 25 strains of S aureus were seeded in the media containing one of the sequential dilutions of both antiseptics. RESULTS: S aureus, Streptococcus mutans, and Streptococcus sobrinus were initially isolated from 45%, 63%, and 28% of the patients, respectively. After rinsing with chlorhexidine, the reductions in the CFUs were above 99% for all the studied microorganisms. In the MID determination, all isolates were inhibited with 1/20 and 1/80 dilutions of cetylpyridinium and chlorhexidine, respectively. Dose-response curves were obtained for both antiseptics. CONCLUSION: Single preprocedural chlorhexidine mouthrinse is effective in reducing salivary microorganisms to levels currently considered safe to perform invasive procedures, and it is still effective in a 1:80 dilution.