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

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.

Effects of implant placement timing and type of soft‐tissue grafting on histological and histomorphometric outcomes in a preclinical canine model

“…These values are smaller than those found in the present study (between 3.51 and 3.66 mm for total tissue thickness, and between 1.63 and 2.55 mm for soft‐tissue thickness). The main difference between these two studies is in the presence of the buccal bone plate: in the previous study, the tissue at the measured levels was predominantly soft tissue because of loss of the buccal plate (Lim et al, 2022). This indicates that the effect of soft‐tissue augmentation might be affected by the presence and thickness of the underlying hard tissue to some extent.…”

“…A previous preclinical canine study evaluated the IP protocol using several regenerative approaches (GBR, CTG and their combination) and found that the median tissue thickness ranged between 0.78 and 1.57 mm (at the IS, IS−1 and IS+1 levels) in the group with CTG (Lim et al, 2022). These values are smaller than those found in the present study (between 3.51 and 3.66 mm for total tissue thickness, and between 1.63 and 2.55 mm for soft‐tissue thickness).…”

Effectiveness of a polycaprolactone scaffold combined with platelet-rich fibrin as guided tissue regeneration materials for preserving an implant-supported overdenture

“…Bone regeneration replacement materials must be biocompatible, biodegradable, easy to apply, effective for bone repair, and highly adaptable to bone defects ( Helal et al, 2016 , Veljanovski et al, 2021 , Wang et al, 2002 ). Various scaffold types and natural or synthetic materials, such as metals, ceramics, and polymers, have been used to stimulate and enhance bone regeneration ( Kim et al, 2021 , Lim et al, 2021 ). Each option has different osteoinductive, osteoconductive, biocompatibility, biodegradability, and chemical properties, necessitating various techniques for their design and application ( Zimmerling et al, 2021 , Eldeeb et al, 2022 ).…”