Impact of treatment modality after tooth extraction on soft tissue dimensional changes: RCT

Abstract

Background: Clinical research related to dimensional change after tooth extraction has mainly focused on the biology of bone, while the effect of soft tissue healing on bone modelling and dimensional changes in post-extraction sites have received little attention. Aim/Hypothesis: To compare soft tissue dimensional changes and relative differences in soft and hard tissue volumes 4 months after single tooth extraction and 3 different treatment modalities: spontaneous healing (SH), alveolar ridge preservation (DBBM/CM) and immediate implant placement (IMPL/DBBM/CM). Materials and Methods: 30 patients requiring single-rooted tooth extraction participated to the trial. After atraumatic tooth extraction, patients were randomly assigned to SH, DBBM/CM with a biomaterial and a collagen matrix seal and IMPL/DBBM/CM with a biomaterial in the gap and a collagen matrix seal. STL files from study casts obtained at baseline and after 4 months were matched to calculate buccal soft tissues linear and volumetric changes. DICOM file from CBCTs were superimposed to STL files allowing the evaluation of soft tissue thickness at baseline and 4 month. Results: No significant differences between groups were observed when analyzing baseline characteristics. All groups demonstrated at 4 months a horizontal reduction in the dimensions of the bucco-lingual tissue contours. Although a tendency towards less reduction was observed in DBBM/CM and IMPL/DBBM/CM group, no statistically significant differences were observed. A similar trend was observed at the buccal aspect, although a statistically significant change was observed at 5 mm, where SH group had significant more resorption (1.66 mm), if compared to DBBM-CM group (1.02 mm) and IMPL/DBBM/CM group (0.85 mm). Buccal volumetric reduction was observed after 4 months in all groups, with no significant differences between them. After 4 months of healing the soft tissue thickness at 3 mm under the most coronal soft tissue point demonstrated a significant mean increase (0.95 mm) for SH group, whereas DBBM/CM and IMPL/and DBBM/CM demonstrated a NO-significant change. Conclusions and Clinical Implications: Treatment modality may be considered less critical in terms of contour alterations on a soft tissue level, since no differences between the three treatment modalities were observed in linear and volumetric changes that occur at the buccal soft tissue profile after tooth extraction. Lack of difference may be due to a significant increase in soft tissue thickness in SH sites. This increase might improve flap manageability if bone augmentation procedures were to be required during implant placement

Is alveolar ridge preservation an overtreatment?

“…Barring hard tissue preservation, the application of ARP aims to optimize soft tissue quality and quantity during socket healing. Although some studies have reported that some ARP techniques and materials are capable of mitigating the extent of soft tissue dimensional changes postextraction, 144,183,185,186 keratinized mucosa width, mucosal thickness, and the external soft tissue contour are not significantly different between alveolar ridges healed with or without ARP 27,72,184 . This lack of difference has been attributed to a great extent to a soft tissue thickening in spontaneous healing sites, especially when the buccal osseous wall is thinner than 1 mm 53,72,184 .…”

“…65,179,180 In a recent trial, 144 and various grafts were used. 49,115,180,181 In contrast to the studies that reported that socket seal utilizing a xenograft and a free gingival graft 182,183 was able to limit the postextraction external soft tissue contour shrinkage, no significant differences in soft tissue contour changes were reported when ARP with a nonresorbable d-PTFE membrane and an allograft, 72 a collagen membrane and a bovine xenograft, 184 a xenograft, and a free gingival graft or a porcine collagen matrix as socket seal 34 were compared with unassisted socket healing. The findings of a recent systematic review and network meta-analysis 185 concluded that hard and soft tissues behave differently after ARP as a response to the choice of the biomaterials used.…”

“…Although some studies have reported that some ARP techniques and materials are capable of mitigating the extent of soft tissue dimensional changes postextraction, 144,183,185,186 keratinized mucosa width, mucosal thickness, and the external soft tissue contour are not significantly different between alveolar ridges healed with or without ARP. 27,72,184 This lack of difference has been attributed to a great extent to a soft tissue thickening in spontaneous healing sites, especially when the buccal osseous wall is thinner than 1 mm. 53,72,184 Based on these data, ARP may be considered less critical for soft than hard tissue preservation and a cost-benefit evaluation should be applied when a tooth-supported bridge/ prosthesis is planned.…”

“…27,72,184 This lack of difference has been attributed to a great extent to a soft tissue thickening in spontaneous healing sites, especially when the buccal osseous wall is thinner than 1 mm. 53,72,184 Based on these data, ARP may be considered less critical for soft than hard tissue preservation and a cost-benefit evaluation should be applied when a tooth-supported bridge/ prosthesis is planned. 184 Furthermore, the application of the ARP procedures frequently involves specific surgical manipulations, that may result in undesirable consequences to the mucosal tissue healing in the hands of less experienced clinicians.…”

“…53,72,184 Based on these data, ARP may be considered less critical for soft than hard tissue preservation and a cost-benefit evaluation should be applied when a tooth-supported bridge/ prosthesis is planned. 184 Furthermore, the application of the ARP procedures frequently involves specific surgical manipulations, that may result in undesirable consequences to the mucosal tissue healing in the hands of less experienced clinicians. Postoperative complications include gingival marginal recession, loss of keratinized tissue, reduced interdental papillary height, reduced tissue thickness, alteration to TA B L E 6 Summary statements one the evidence pertaining to the key objectives of alveolar ridge preservation (ARP) against unassisted socket healing (USH).…”