The association of clinical and microbiologic parameters with histologic observations in relatively healthy peri-implant conditions- a preliminary short-term in vivo study.

PURPOSE: To determine whether clinical findings-bleeding on probing, pocket depth, recession, and bacterial sampling-correlate with histologic outcomes in relatively healthy peri-implant soft tissues in people. MATERIALS AND METHODS: In this cross-sectional study, a convenience sample of 20 edentulous subjects received two endosseous mandibular implants each. The abutments were either zirconia (ZrO2) or titanium (Ti) (nonsubmerged implant placement, within-subject comparison, leftright randomization). Sulcular bacterial sampling and assessment of probing pocket depth, recession, and bleeding on probing were performed 3 months postsurgery. Mucosal biopsy specimens were obtained, and the blood vessel density and a score on an inflammation grading scale were determined. RESULTS: Simple linear and linear regression models revealed that the clinical or microbiologic parameters were not associated with either of the histologic parameters. The soft tissues impressed as healthy, regardless of the abutment material. CONCLUSIONS: The peri-implant mucosa around ZrO2and Ti abutments was considered healthy in most situations when examined histologically after 3 months but showed variation in clinical and microbiologic parameters.

An exploratory study on assessment of gingival biotype and crown dimensions as predictors for implant esthetics comparing caucasian and Indian subjects.

Gingival biotype and crown dimensions may be important predictors for the esthetic outcome of surgical procedures. However, the visual distinction between "thick" and "thin" biotype may not be a suitable predictive parameter of surgical outcome. Intraoral photographs of 73 Indian and Dutch subjects were matched with respect to age and gender and were used to determine the gingival biotype (subjective assessment) and crown dimensions (objective assessment). Intraobserver and interobserver agreement was determined for subjective measurements (Cohen's kappa), and the error of the method was calculated for the objective measurements (Dahlberg formula). Intraobserver agreement for the subjective assessment of gingival biotype was adequate (κ = 0.49-0.60), but interobserver agreement was poor (κ = 0.10), whereas the error of the method for objective assessment of crown dimensions was small. The mean crown width-length angle is smaller in Dutch as compared to Indian subjects in this sample (P < .05). Crown dimensions may be a more quantitative approach and could become a future norm to predict outcomes of implant restorative and surgical procedures, bearing in mind that cross-cultural differences may be present.

A comparative study to evaluate the effect of two different abutment designs on soft tissue healing and stability of mucosal margins.

AIM: To evaluate the effect of two different abutment designs on soft tissue healing and the stability of the mucosal margin in vivo. MATERIALS AND METHODS: Twenty-nine subjects received two, non-adjacent endosseous implants in the esthetic zone. Subsequently, conventional (control) and curved abutments (experimental) were placed in combination with a temporary restoration (left-right randomization). Plaster models of the healed sites were made to assess the stability of the soft tissues at baseline and after 6 weeks. To measure deseating force, a dontrix gauge was used while removing the abutments after 6 weeks. RESULTS: Although visually, differences in the transmucosal area were observed, the differences in marginal recession and in deseating force between abutments from the experimental and the control group never reached a statistically significant level. In general, some gain in soft tissue height was seen in both groups. Angled abutments elicited recession at all buccal sites (P = 0.003-0.02). CONCLUSION: Abutments with a circumferential groove do not lead to a different response of the mucosal margin compared with a regular abutment, and are no more resistant upon removal than regular abutments after 6 weeks of function.

Soft tissue response to zirconia and titanium implant abutments: an in vivo within-subject comparison.

AIM: To compare the health of the soft tissues towards zirconia and titanium abutments in man, as observed using histological data. MATERIAL AND METHODS: Twenty patients received two mandibular implants with either a zirconia or titanium abutment (split mouth study design, left-right randomization). After 3 months soft tissue biopsies were prepared for histological evaluation. They were subjected to blind evaluation. The number of blood vessels per surface unit and an inflammation grading scale score ranging from 1 to 4 were determined. RESULTS: Paired samples from 17 patients were suitable for analysis, 3 with unsevered implant-abutment connections and 14 solely containing soft tissue. All showed a well-keratinized stratified squamous epithelium which was continuous with the barrier (junctional) epithelium that faced the abutment surface. The normal epithelial build-up could be recognized with little signs of inflammation. No statistically significant difference in tissues adjacent to zirconia and titanium abutment surfaces were seen with respect to vascular density (20.5 SD 4.4 and 20.7 SD 3.2) or inflammation grading scale scores (3.2 SD 0.7 versus 3.1 SD 0.7). CONCLUSION: No differences in soft tissue health were seen in peri-implant mucosa adjacent to zirconia and titanium abutment surfaces.

The effect of zirconia and titanium implant abutments on light reflection of the supporting soft tissues.

OBJECTIVES: To determine the difference in light reflection of oral mucosa covering titanium (Ti) or zirconia (ZrO(2)) abutments as it relates to the thickness of the covering mucosa. MATERIAL AND METHODS: Fifteen anterior implants (Astra Osseo speed(®)) in 11 patients were fitted with a Ti or a ZrO(2) abutment (cross-over, within-subject comparison). Hyper-spectral images were taken with a camera fitted on a surgical microscope. High-resolution images with 70 nm interval between 440 and 720 nm were obtained within 30 s (1392 × 1024 pixels). Black- and white-point reference was used for spatial and spectral normalization as well as correction for motion during exposure. Reflection spectra were extracted from the image on a line mid-buccal of the implant, starting 1 mm above the soft tissue continuing up to 3 mm apically. RESULTS: Median soft tissue height is 2.3 mm (min: 1.2 mm and max: 3.1 mm). The buccal mucosa rapidly increases in the thickness, when moving apically. At 2.2 mm, thickness is 3 mm. No perceivable difference between the Ti and ZrO(2) abutment can be observed when the thickness of the mucosa is 2±0.1 mm (95% confidence interval) or more. CONCLUSION: It is expected that the difference in light reflection of soft tissue covering Ti or ZrO(2) abutments is no longer noticeable for the human eye when the mucosa thickness exceeds 2 mm. Haemoglobin peaks in the reflection spectrum can be observed and make hyper-spectral imaging a practical and useful tool for measuring soft tissue health.

Early bacterial colonization and soft tissue health around zirconia and titanium abutments: an in vivo study in man.

AIM: To compare the early bacterial colonization and soft tissue health of mucosa adjacent to zirconia (ZrO(2)) and titanium (Ti) abutment surfaces in vivo. MATERIALS AND METHODS: Twenty edentulous subjects received two endosseous mandibular implants. The implants were fitted with either a ZrO(2) or a Ti abutment (non-submerged implant placement, within-subject comparison, left-right randomization). Sulcular bacterial sampling and the assessment of probing pocket depth, recession and bleeding on probing were performed at 2 weeks and 3 months post-surgery. Wilcoxon matched-pairs, sign-rank tests were applied to test differences in the counts of seven marker bacteria and the clinical parameters that were associated with the ZrO(2) and Ti abutments, at the two observation time points. RESULTS: ZrO(2) and Ti abutments harboured similar counts of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Peptostreptococcus micros, Fusobacterium nucleatum and Treponema denticola at 2 weeks and 3 months. Healthy clinical conditions were seen around both ZrO(2) and Ti abutments at all times, without significant differences in most clinical parameters of peri-implant soft tissue health. Mean probing depths around Ti abutments were slightly deeper than around ZrO(2) abutments after 3 months (2.2 SD 0.8 mm vs. 1.7 SD 0.7 mm, P=0.03). CONCLUSIONS: No difference in health of the soft tissues adjacent to ZrO(2) and Ti abutment surfaces or in early bacterial colonization could be demonstrated, although somewhat shallower probing depths were observed around ZrO(2) abutments after 3 month.