Clinical evaluation and patient related outcomes of one- and two-piece zirconia implants at five years of loading: A case series study.

OBJECTIVE: The objective of this study was to investigate the survival and biological and mechanical complications of one-piece and two-piece zirconia implants at five years of loading. MATERIALS AND METHODS: Consecutive patients receiving zirconia implants were studied, collecting data at five years of loading on their clinical history, peri-implant health status, mechanical complications, esthetic results, and patient related outcomes. RESULTS: The study included 18 patients with 29 implants. The survival rate was 86% in implant-based analysis and 78% in patient-based analysis. There were no cases of peri-implantitis, but mucositis was present in 53% of implants. A mean of 4.1 ± 0.81 mm was obtained for probing depth and 1.6 ± 0.9 mm for crestal bone loss (radiographic assessment). There were no implant fractures. Major (10%) and minor (10%) prosthesis complications were observed. The esthetic outcome was moderate to almost perfect, with a high level of patient satisfaction. No significant association was found between survival rate and the presence of mucositis around one- or two-piece implants or any other study variable. CONCLUSIONS: The survival rate is low for one- and two-piece zirconia implants. Both types of implants demonstrated a low mechanical complication rate. The incidence of periimplantitis is low but mucositis is present in 50%. Patient satisfaction related to esthetics and function is moderate to high. They represent a good option for patients requiring an alternative to titanium implants. CLINICAL RELEVANCE: Zirconia implants appear to be an alternative to the titanium option and may be indicated for patients requiring "metal-free" restorations.

Comparative in vitro study of two methods for gingival biotype assessment.

BACKGROUND: The gingival thickness seems to have an important role in different dental treatments. There are different methods of quantifying this thickness, but it is not known which of them can be the most effective. The objective to assess the accuracy of two different methods for gingival thickness measurement: the transgingival needle probing (TGNP) and the tension-free caliper (TFC) in an in vitro model, by comparing them with direct physical measurements (reference standard). MATERIAL AND METHODS: Gingival thickness (GT) was evaluated in 27 female pigs with four implant sites 1, 2 and 3mm from the gingival margin with three different methods: 1) transgingival needle probing 2) tension-free caliper and 3) Direct visualization after making a incision in the mucosa and measuring GT with a periodontal probe. Wilcoxon test for paired samples were used with a confident level of 95%. RESULTS: A total of 324 points were measured, 59% of the sites presented a thin biotype with DV, it was correctly assessed with the TGNP in 84% of the times and in 86% with the TFC. 41% of the sample presented thick biotype, 76% was the percentage measured with the TGNP and 0% of the sites evaluated with TFC resulted in this biotype. CONCLUSIONS: Transgingival needle probing constitutes an accurate method when measuring GT at different levels. Tension free caliper is not a good tool for assessing the gingival biotype as long as it is unable to predict thick biotype. Key words:Periodontal Biotype, Gingival Thickness, Periodontal Tissue and Diagnosis.

Impact of abutment material on peri-implant soft tissue color. An in vitro study.

OBJECTIVES: The objectives of the present study is to determine the differences in peri-implant soft tissue color with the utilization of titanium, titanium gold-plated, white zirconia, Vita Classical (VC) A4-shaded zirconia, and fluorescent white zirconia abutments and to establish the influence of gingival thickness on the resulting color. METHODS: Four implants were contralaterally inserted in 19 fresh pig mandibles, and the color of the peri-implant mucosa with the different abutments was spectrophotometrically measured at 1-, 2-, and 3-mm height from the margin. RESULTS: At 1-mm height, titanium significantly differed from all zirconia abutments in lightness (L*), chroma along red axis (a*), and chroma along yellow-blue axis (b*) parameters. At 2 mm, all zirconia abutments differed from titanium in b* but only fluorescent zirconia in a*. At 3 mm, titanium differed from VC A4-shaded and fluorescent zirconia abutments in b*. At soft tissue thicknesses <1 and 1-2 mm, titanium differed from fluorescent zirconia in a* and b* and from VC A4-shaded zirconia in b*; at thickness >2 mm, no differences were found among abutments. All abutments differed from natural teeth in a* and b* at all heights and thicknesses except for fluorescent zirconia at thickness >2 mm. The Euclidean distance (ΔΕ) differed between titanium abutments and gold, VC A4, and fluorescent zirconia at <1- and 1-2-mm thicknesses. CONCLUSION: The natural gingival color was not reproduced with any abutment at gingival thicknesses <2 mm. The worst color match was with titanium abutments and the best with fluorescent zirconia, followed by VC A4-shaded zirconia. At gingival thicknesses >2 mm, no differences were detected among abutments. CLINICAL RELEVANCE: This study demonstrates that the type of abutment and the gingival thickness affect the resulting peri-implant gingival color.

Factors involved in the spectrophotometric measurement of soft tissue: A clinical study of interrater and intrarater reliability.

STATEMENT OF PROBLEM: The reliability of spectrophotometric measurements of gingival color has not been tested. PURPOSE: The purpose of this study was to evaluate the repeatability and reproducibility of gingival color measurements with a digital spectrophotometer. Measurement error was estimated by determining the interrater agreement and by repeating measurements in different illumination environments with and without contact of the device with the gingiva. MATERIAL AND METHODS: Two trained examiners measured the gingival shade around 30 central incisors with a spectrophotometer with and without external illumination and with and without contact of the device with the gingiva. Color data obtained (CIELab color coordinates; L*, c*, h*, a*, b*) were analyzed with the intraclass correlation coefficient (ICC) and the Student t test for paired samples. RESULTS: Mean L*, c*, a*, and b* values differed significantly between measurements made with and without contact of the device with the tissue, but no difference was found in h* values. An ICC of >0.9 was obtained for interrater and intrarater agreements in all cases. Shade measurements did not differ between the presence and absence of stable ambient light. CONCLUSIONS: The repeatability and reproducibility of soft tissue shade measurements were almost perfect (ICC >0.9) under the examination conditions tested. The measurements were affected by pressure but not by ambient light.

The correlation between crown-implant ratios and marginal bone resorption: a preliminary clinical study.

PURPOSE: The crown-implant ratio is defined as the physical relationship between each individual restoration's parts located both inside and outside the bone. This relationship represents the physical concept of a type I lever, which may be of biomechanical importance in implant treatment outcomes. MATERIALS AND METHODS: Specific patient data related to fixed implant prostheses were retrieved and studied in an effort to clinically and radiographically correlate crown-implant ratios. RESULTS: Recorded marginal bone resorption around implants (2.11 +/- 1.30 mm) at the end of a defined observation period did not correlate with the measured crown-implant ratio, which yielded values between 0.43 and 1.5 mm (P > .05). CONCLUSION: The mechanical determinants of implant success or failure are still not defined. It has been postulated that an increase in both crown-tooth, and comparably crown-implant, ratios would lead to a resultant increase in the magnitude of nonaxial forces transmitted to the tooth or implant. This could then lead to an increased vulnerability of either tooth or implant abutments to supporting bone loss. However, additional factors appear to impact long-term bone maintenance behavior around either type of abutment. Within the limited scope of this study, crown-implant ratios were not associated with recorded peri-implant bone loss. Int J Prosthodont 2010;23:33-37.