Human gingival fibroblast proliferation on materials used for dental implant abutments: a systematic review.

PURPOSE: To conduct a systematic review to evaluate the influence of materials and surfaces used for dental implant abutments on the proliferation of human gingival fibroblasts. MATERIALS AND METHODS: The focus question of this review was: Which material/surface characteristics used for dental implant abutments influence/enhance proliferation of human gingival fibroblasts? The Medline/PubMed, Embase, and Cochrane Library databases were searched using "gingiva," "fibroblasts," "proliferation," and "dental implant abutments" as main keywords with AND/OR as Boolean operators. In vitro studies reporting 3 to 4 or 6 to 7 days of cell proliferation, surface hydrophilicity, and roughness were included. A quality assessment of the selected studies was performed using the web-based Science in Risk Assessment and Policy (SciRAP) tool. RESULTS: The search identified 1,144 studies, and 44 were eligible for inclusion. The average reporting quality SciRAP score was 82.87 ± 10.68, and the average methodologic quality SciRAP score was 87.35 ± 10.55. Machined, polished, and coated titanium and zirconia surfaces were most commonly investigated. Several studies analyzed aluminum oxide, cobalt-chrome-molybdenum alloy, lithium disilicate, polyether ether ketone, polymer-infiltrated ceramic network, and bioglass. The best cell proliferation was observed on zirconia and on titanium harboring nanotubules or microgrooves. UV treatment, polydopamine, and nitride coatings also improved cell proliferation. Due to the heterogeneity of the data, no correlation could be established between cell profileration and surface hydrophilicity or roughness. However, surface roughness in the range of Ra = 15 to 145 nm and Sa = 19 to 500 nm on titanium and zirconia proved most suitable. CONCLUSION: Titanium surfaces with directional guidance patterning and zirconia surfaces best supported cell proliferation during the first week of cell culture. Lack of standardization in surface definitions (machined or polished), methodology, and reporting prevented analytical comparison and should be imposed in future studies.

Telescopic Crowns On Implants And Teeth: Evaluation Of A Clinical Study After 8 to 12 Years.

PURPOSE: To evaluate the outcome of a clinical study on telescopic-crown-retained removable dental prostheses (TCR-RDPs) on implants or implants and teeth after 8 to 12 years. MATERIALS AND METHODS: Between 1999 and 2002, 39 (41 jaws) patients received implant- or combined tooth-implant-supported TCR-RDPs in the maxilla and/or mandible. One-stage surgery was performed, and after a conventional healing period, TCR-RDPs were inserted. Thirty-one patients (33 prostheses) were available for annual follow-up investigations with a standardized protocol from 2010 until 2013. Cumulative survival and success of the abutments was estimated using the Kaplan-Meier method, and a Cox regression model was used to identify potential predictors for abutment complications. Patients' oral health-related quality of life (OHRQoL) was measured by means of the Oral Health Impact Profile (OHIP). RESULTS: After a mean observation period of 11.3 ± 1.1 years, all restorations were still functioning successfully. Two implants and 10 abutment teeth were lost, leading to significantly different implant and tooth survival rates of 97.6% (SE ± 1.7%) and 81.8% (SE 5.3%; P = .007). Implants placed in the mandible, and those in the group with a higher number of abutments (5 to 6 vs 2 to 4) showed higher success rates. The success rates of abutment teeth were not influenced by location (mandible vs maxilla) or number of abutments (5 to 6 vs 2 to 4). CONCLUSION: Implant- or combined tooth-implant-supported TCR-RDPs provided a satisfying treatment option for patients with severely reduced dentition in the long term. Due to the small sample size, the results presented should be interpreted with caution.

Influence of UV Irradiation and Cold Atmospheric Pressure Plasma on Zirconia Surfaces: An In Vitro Study

PURPOSE: To compare the influence of ultraviolet (UV) irradiation and cold atmospheric pressure plasma (CAP) treatment on surface structure, surface chemistry, cytocompatibility, and cell behavior on zirconia in vitro. MATERIALS AND METHODS: Zirconia samples (TZ-3YSBE) were treated by UV irradiation, oxygen plasma, or argon plasma for 12 minutes each and compared with the nontreated samples. Surface analysis was conducted using scanning electron microscopy, roughness analysis, and x-ray photoelectron spectroscopy. Cell proliferation, viability, and cell attachment as well as cytotoxicity were evaluated using MC3T3-E1 murine osteoblasts cultivated directly on the zirconia samples. RESULTS: Surface structure and roughness were not affected by the surface treatments. CAP and UV irradiation significantly reduced organic material and increased the surface oxidation on the zirconia samples. Furthermore, CAP and UV treatment significantly decreased the contact angle on the zirconia samples, indicating superhydrophilicity. Cell attachment was significantly increased on oxygen plasma-treated zirconia samples compared with the nontreated samples at all times (P < .001). After 24 and 48 hours, cell proliferation and viability (P < .001) were significantly increased on oxygen plasma-treated samples in comparison with the nontreated, UV-treated, and argon plasma-treated samples. Neither UV nor CAP treatment led to cytotoxicity. CONCLUSION: In vitro, surface treatment by UV irradiation or CAP causes a significant reduction of organic material, increases the hydrophilicity of zirconia, and improves the conditions for osteoblasts. Results stipulate that treatment of zirconia surfaces with oxygen plasma may favor cell proliferation.

The gingival biotype: measurement of soft and hard tissue dimensions - a radiographic morphometric study.

BACKGROUND: Gingival biotypes have been reported to influence the outcome of restorative therapies. The aim of this study was to evaluate the correlation of different morphometric parameters with the thickness of the buccal gingiva and alveolar bone at different apico-coronal levels. METHODS: In 60 periodontally healthy subjects, the central maxillary incisor was examined. Clinical parameters included the crown width/crown length ratio (CW/CL), gingival width (GW), gingival scallop (SC) and transparency of the periodontal probe through the gingival sulcus (TRAN). Gingival and alveolar bone dimensions were assessed on parallel profile radiographs. RESULTS: Crown width/crown length ratio was positively correlated with the thickness of the gingiva at the cementoenamel junction (G3) (r = 0.47) and to the thickness of the alveolar crest (A1) (r = 0.46); whereas SC had a weak negative and GW had a moderate positive correlation with all radiographic measurements. TRAN had a stronger negative relation to the thickness at the free gingiva (r = -0.42) than to other tissue thicknesses. All gingival thickness values were correlated with A1 value. Multivariate models identified CW/CL and GW as significant predictors for G3 value, whereas CW/CL was a significant predictor for A1 value. CONCLUSION: Crown width/crown length ratio and GW could represent surrogate parameters to anticipate the gingival thickness at the cementoenamel junction, whereas CW/CL might also be an indicator for alveolar bone crest thickness. Periodontal probing has a limited prognostic value for these tissue dimensions.

Impact of rhBMP-2 on regeneration of buccal alveolar defects during the osseointegration of transgingival inserted implants.

OBJECTIVE: New approaches to enhance vertical bone regeneration in clinically relevant implant models are needed. Therefore, we analyzed the impact of recombinant human bone morphogenic protein 2 (rhBMP-2) on the healing of large buccal alveolar defects during osseointegration of transgingivally inserted implants. STUDY DESIGN: Twenty-four dental implants were inserted transgingivally in the mandibles of 6 labrador/golden retriever cross-bred dogs. Before implantation, a standardized buccal bone defect was created and refilled with either calcium phosphate as a carrier containing rhBMP-2 or calcium phosphate alone. Either ceramic abutments that enabled immediate implant loading or healing distance collars to prevent loading were mounted. Sixteen weeks after intervention, bone implant units were analyzed by radiofrequency analysis and histomorphometry. RESULTS: In total, 14 implants (58.3%) were available for further analysis. The mean depth of the bone defects, the gain of regenerated bone, the vertical osseointegration of the implants, and the bone-to-implant contact in the newly formed bone were slightly greater in the rhBMP-2-containing samples. In contrast, the osseointegration in the preexisting bone was even superior within the non-rhBMP-2-treated specimen. However no differences were statistically significant. CONCLUSIONS: When rhBMP-2-conducted bone regeneration was compared with control samples, no significant differences of newly formed bone were found at the bone-implant interface. The amounts of rhBMP-2 applied do not seem suitable to enhance implant osseointegration in large buccal defects.

Effect of recombinant human bone morphogenetic protein-2 in dehiscence defects with non-submerged immediate implants: an experimental study in Cynomolgus monkeys.

BACKGROUND: Alveolar ridge aberrations commonly compromise optimal dental implant installation. To offset any variance between an aberrant alveolar ridge and prosthetic designs, bone augmentation procedures become necessary. The objective of this study was to evaluate bone formation and osseointegration at alveolar dehiscence defects following augmentation of the defect site with recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge carrier (ACS) at dental implant installation including transmucosal positioning of the dental implant. METHODS: Four adult male Cynomolgus monkeys received dental implants in contralateral extraction socket sites with surgically created 6 x 4 mm buccal dehiscence defects following elevation of mucoperiosteal flaps. Contralateral sites received rhBMP-2/ACS (rhBMP-2 at 1.5 mg/ml; 0.1 mg/defect) or served as sham-surgery controls. The flaps were adapted and sutured around the healing abutments leaving the implants in a transmucosal position. The animals were sacrificed at 16 weeks postsurgery and block sections of the implant sites were harvested and prepared for histometric analysis. RESULTS: One dental implant from each treatment group failed to osseointegrate. Another 3 dental implants (sham-surgery controls) failed to osseointegrate with newly-formed bone in the defect area. Thus, 7 of 8 defect sites (4/4 animals) receiving rhBMP-2/ACS compared to 4 of 8 sites (2/4 animals) receiving sham-surgery exhibited evidence of osseointegration with newly formed bone in the defect area. Mean +/- SD defect height amounted to 5.3 +/- 0.2 and 5.4 +/- 0.1 mm for the rhBMP-2/ACS and sham-surgery sites, respectively. Vertical bone gain in rhBMP-2/ACS treated defects (3.9 +/- 0.3 mm) did not differ significantly from that in the sham-surgery control (3.7 +/- 0.4 mm; P > 0.05; paired t-test, N = 4). There were also no significant differences noted for coronal bone-implant contact (3.0 +/- 0.6 versus 3.6 +/- 0.5 mm), and bone-implant contact within the defect site (28.5% +/- 15.1% versus 27.4% +/- 31.7%) and within resident bone (46.9% +/- 26.8% versus 47.8% +/- 39.4%) for the rhBMP-2/ACS and control sites, respectively. CONCLUSIONS: The observations in this study point to a substantial native osteogenic potential of the alveolar process that has previously not been explored and show that surgical reentry observations of new bone formation may not necessarily indicate that osseointegration has occurred. Bone formation in control defects was substantially greater than predicted, limiting the value of adding an osteoinductive biologic construct.