Bone-to-implant contact after maxillary sinus floor augmentation with Bio-Oss and autogenous bone in different ratios in mini pigs

Bone-to-implant contact after maxillary sinus floor augmentation with Bio-Oss and autogenous bone in different ratios in mini pigs:

Abstract

Objectives

The objective was to test the hypotheses: (i) no differences in bone-to-implant contact formation, and (ii) no differences between the use of autogenous mandibular or iliac bone grafts, when autogenous bone, Bio-Oss mixed with autogenous bone, or Bio-Oss is used as graft for the maxillary sinus floor augmentation.

Material and methods

Bilateral sinus floor augmentation was performed in 40 mini pigs with: (A) 100% autogenous bone, (B) 75% autogenous bone and 25% Bio-Oss, (C) 50% autogenous bone and 50% Bio-Oss, (D) 25% autogenous bone and 75% Bio-Oss, or (E) 100% Bio-Oss. Autogenous bone was harvested from the iliac crest or the mandible and the graft composition was selected at random and placed concomitant with the implant placement. The animals were euthanized 12 weeks after surgery. Bone-to-implant contact was estimated by stereological methods and summarized as median percentage with 95% confidence interval (CI). Bone-to-implant contact formation was evaluated by fluorochrome labelling and assessed by median odds ratios (OR) with 95% (CI).

Results

Median bone-to-implant contact was: (A) 42.9% (95% CI: 32.1–54.5%), (B) 37.8% (95% CI: 27.1–49.9%), (C) 43.9% (95% CI: 32.6–55.9%), (D) 30.2% (95% CI: 21.6–40.3%), and (E) 13.9% (95% CI: 11.4–16.9%). Bone-to-implant contact was significantly higher for A, B, C, D as compared to E (P < 0.0001). Bone-to-implant contact was not significantly influenced by the ratio of Bio-Oss and autogenous bone (P = 0.19) or the origin of the autogenous bone (P = 0.72). Fluorochrome labelling revealed extensive variation in bone-to-implant contact formation over time. The labelling at weeks 2–3 was significantly increased with A compared to E (OR = 8.1 CI: 5.0–13.1, P < 0.0001), whereas E showed a significantly increased labelling at weeks 8–9 compared to A (OR = 0.5 CI: 0.3–0.7, P = 0.0028).

Conclusions

The hypothesis of no differences in bone-to-implant contact between the various treatment modalities was rejected since the bone-to-implant contact was significantly increased with autogenous bone or Bio-Oss mixed with autogenous bone as compared to Bio-Oss. Early bone-to-implant contact formation was more advanced with autogenous bone. No differences between the use of mandibular or iliac bone grafts were observed since the bone-to-implant contact was not significantly influenced by the origin of the bone graft.

Significance of keratinized mucosa around dental implants: a prospective comparative study

Significance of keratinized mucosa around dental implants: a prospective comparative study:

Abstract

Objective

The aim of this investigation was to evaluate the significance of keratinized mucosa (KM) around dental implants both clinically and biochemically for 12 months.

Material and methods

Fifteen edentulous patients treated with implant-retained overdentures in edentulous mandible (four implants per patient). Based on the presence of keratinized mucosa on the buccal surfaces, implants were divided into two groups: Implants having minimal 2 mm of KM on their buccal surfaces and implants having no KM on their buccal surfaces. Thirty-six implants were included in the evaluations; 19 implants in 15 patients had minimal 2 mm of KM on their buccal surfaces and 17 implants in 15 patients had no KM on their buccal surfaces. Clinical measurements of Plaque Index, Gingival Index, probing depths, and Bleeding on Probing were performed and peri-implant crevicular fluid (PICF) were collected immediately before loading (baseline) and at 6th, 12th months after loading. Interleukin-1 beta (IL-1 β) and tumor necrosis factor-alpha (TNF-α) have been assessed in the crevicular fluid. Results were analyzed by repeated-measures of variance (ANOVA) and Wilcoxon signed rank tests.

Results

After 12 months of evaluation the results of ANOVA showed that implants with KM had lower levels of TNF-α total amounts than implants without KM (P < 0.05). Additionally, TNF-α total amounts were significantly higher at 12^th month compared to baseline for implants without KM (P < 0.05). Plaque index and Gingival index values were also found significantly higher for implants without KM (P < 0.05). For IL-1 β and PICF volume levels the differences between the implant groups were non significant, whereas the differences between the periods were significant. (P < 0.05) Additionally, both of the groups had higher levels of PII and BoP scores when compared to baseline (P < 0.05).

Conclusions

The results of this study showed that an adequate band of keratinized mucosa was related with less plaque accumulation and mucosal inflammation as well as pro-inflammatuar mediators, suggesting that it may be critical especially for plaque control and plaque associated mucosal lesions around dental implants.