Tissue integration of zirconia and titanium implants with and without buccal dehiscence defects

Immediate placement of one-piece zirconia implants with or without xenograft into the buccal gap. Soft tissues as secondary outcomes of an experimental in vivo study

OBJECTIVE

To histologically evaluate soft tissue healing following immediately placed one-piece zirconia implant and grafting a xenograft into the buccal gap.

MATERIALS AND METHODS

The third and fourth premolars (PM3 and PM4) in both quadrants of the mandible of nine dogs were used for this experiment. Those teeth were removed flapless and implants were placed into the distal sockets in a lingual position. In one side of the jaw, the gap between the implant and the socket walls was grafted (test) while no grafting was performed in the contralateral side (control), randomly selected. After 6 months of healing, biopsies were obtained and prepared for histological analysis. Soft tissue measures like supracrestal soft tissue height (STH), length of barrier epithelium (BE), and connective tissue (CTC) were measured at buccal and lingual surfaces.

RESULTS

The marginal mucosa was in a coronal position on the test side compared with the control side. At the buccal surface, the BE was longer in the test side than in the control side, while the CTC was longer in the control side than in the test side. For the STH (BE + CTC), the difference between the groups was not statistically significant.

CONCLUSION

The placement of a xenograft into the gap between a 1-piece zirconia implant and the buccal wall in dogs modified the process of soft tissue healing, providing less soft tissue recession. The gap size seems to have a modifying effect on the application of this protocol.

Crestal bone response to loaded zirconia and titanium implants: a radiographic and histometric analysis in canines

OBJECTIVES

To evaluate the crestal bone response to a two-piece zirconia implant compared with a control titanium implant using periapical radiographs (PAs) and histometry.

MATERIALS AND METHODS

Thirty zirconia and 30 titanium implants were placed in healed posterior mandibles of five canines. Full-ceramic single-tooth restorations were cemented after 6 weeks of healing. Three observers measured the distance between the implant shoulder and the crestal bone (DIB) at placement, loading, and harvesting after 4 or 16 weeks in function. The influence of implant material and loading time on DIB as well as the inter-observer agreement were analyzed. Additionally, histometric distance between implant shoulder and most coronal bone-to-implant contact (IS-cBIC) was compared with DIB.

RESULTS

Mean DIB values increased between 4 and 16 weeks of loading for both zirconia (from 1.66 to 2.25 mm; P < 0.0001) and titanium (from 1.81 to 1.95 mm; P = 0.06). Zirconia yielded mean IS-cBIC values of 2.18 mm and 2.48 mm (P < 0.001) and titanium 2.23 mm and 2.34 mm (P = 0.27) after 4 and 16 weeks, respectively. The raters reached an excellent intraclass correlation coefficient. PAs underestimated the bone loss on average by 0.39 mm.

CONCLUSIONS

Zirconia implants showed a greater increase of DIB during early healing and function than titanium.

CLINICAL RELEVANCE

Crestal peri-implant tissue dimensions may show more pronounced changes around two-piece zirconia implants during early healing. PAs may underestimate peri-implant bone loss.

Efficacy of lateral bone augmentation performed simultaneously with dental implant placement: A systematic review and meta-analysis

OBJECTIVES

To analyse the evidence regarding the efficacy of lateral bone augmentation procedures in terms of defect resolution in cases of horizontal ridge deficiencies after implant placement.

MATERIALS AND METHODS

Included studies met the following inclusion criteria: randomized controlled trials (RCTs) or controlled clinical trials (CCTs), re-entry procedure to assess defect resolution, minimum of 10 patients (5 per group). Meta-analyses were performed whenever possible, including subgroup analysis based on membranes and grafting materials.

RESULTS

Twenty-eight publications (20 short-term, 8 follow-up studies) were included. The most often used type of intervention was a xenogeneic particulated grafting material (XE) and a resorbable collagen membrane (CM). The mean defect height at baseline amounted to 5.1 mm (range 2.4-7.8) and decreased to a mean of 0.9 mm (range 0.2-2.2) at re-entry, and the mean defect resolution was 81.3% (range 56.4%-97.1%). Defect height reduction was not significantly different using CM+XE as control treatment compared to the combined data of the respective test groups [n = 11; weighted mean difference (WMD) = -0.006 mm; 95% CI, -0.61, 0.60; p = 0.985]. The absence of any lateral bone augmentation was less favourable than the conjunction of a membrane and a bone grafting material (n = 1; MD = -1.96 mm; 95% CI, -3.48, -0.44; p = 0.011). The lack of a grafting material was less favourable than the conjunction of grafting material and membrane (n = 1; MD = -2.44 mm; 95% CI, -4.53, -0.35; p = 0.022), and the addition of a membrane compared to a grafting material alone was more favourable (n = 3; WMD = 0.97 mm; 95% CI, 0.31, 1.64; p = 0.004).

CONCLUSIONS

Lateral bone augmentation is a successful treatment modality. For optimal defect height reduction, a barrier membrane and a grafting material should be combined.

Tissue integration of zirconia and titanium implants with and without buccal dehiscence defects-A histologic and radiographic preclinical study

OBJECTIVE

To histologically and radiographically evaluate soft (primary outcome) and hard tissue integration of two-piece titanium and zirconia dental implants with/without buccal dehiscence defects.

MATERIALS & METHODS

In six dogs, five implants were randomly placed on both sides of the mandible: (a) Z1: a zirconia implant (modified surface) within the bony housing, (b) Z2: a zirconia implant (standard surface) within the bony housing, (c) T: a titanium implant within the bony housing, (d) Z1_D: a Z1 implant placed with a buccal bone dehiscence (3 mm in height, identical width to implant body), and (e) T_D: a titanium implant placed with a buccal bone dehiscence. Two weeks of healing and 6 months of loading were applied on each hemi-mandible, respectively.

RESULTS

The median level of the margo mucosae shifted more apically over time in all groups (borderline statistical significance in groups Z1_D: -0.52 mm and T_D: -1.26 mm). The median height of the peri-implant mucosa in groups Z1_D and T_D was greatest at 2 weeks and 6 months, but the linear change in the peri-implant mucosa was statistically significant only for group T_D over time (-1.45 mm). Z1 demonstrated a higher bone-to-implant contact compared to Z2 and T. Minimal change of radiographic marginal bone levels in all groups was observed (<1 mm).

CONCLUSION

When buccal dehiscence was presented, titanium implants presented significant loss of peri-implant mucosal height compared to zirconia implants with a modified surface, due to greater apical shift of the margo mucosae. A modified zirconia surface enhanced osseointegration.