J Periodontal Implant Sci.  2022 Apr;52(2):170-180. 10.5051/jpis.2104040202.

Immediate implant placement in conjunction with guided bone regeneration and/or connective tissue grafts: an experimental study in canines

• Lim HC
• Paeng KW
• Kim MJ
• Jung RE
• Hämmerle CH
• Jung UW
• Thoma DS

• KMID: 2557789
• DOI: http://doi.org/10.5051/jpis.2104040202

Abstract

Purpose
This study was conducted to assess the effect of hard and/or soft tissue grafting on immediate implants in a preclinical model.
Methods
In 5 mongrel dogs, the distal roots of P2 and P3 were extracted from the maxilla (4 sites in each animal), and immediate implant placement was performed. Each site was randomly assigned to 1 of the following 4 groups: i) gap filling with guided bone regeneration (the GBR group), ii) subepithelial connective tissue grafting (the SCTG group), iii) GBR and SCTG (the GBR/SCTG group), and iv) no further treatment (control). Non-submerged healing was provided for 4 months. Histological and histomorphometric analyses were performed.
Results
Peri-implant tissue height and thickness favored the SCTG group (height of periimplant mucosa: 1.14 mm; tissue thickness at the implant shoulder and ±1 mm from the shoulder: 1.14 mm, 0.78 mm, and 1.57 mm, respectively; median value) over the other groups. Bone grafting was not effective at the level of the implant shoulder and on the coronal level of the shoulder. In addition, simultaneous soft and hard tissue augmentation (the GBR/SCTG group) led to a less favorable tissue contour compared to GBR or SCTG alone (height of periimplant mucosa: 3.06 mm; thickness of peri-implant mucosa at the implant shoulder and ±1 mm from the shoulder: 0.72 mm, 0.3 mm, and 1.09 mm, respectively).
Conclusion
SCTG tended to have positive effects on the thickness and height of the periimplant mucosa in immediate implant placement. However, simultaneous soft and hard tissue augmentation might not allow a satisfactory tissue contour in cases where the relationship between implant position and neighboring bone housing is unfavorable.

Keyword

Alveolar ridge augmentation; Animal experimentation; Dental implantation