Clinical evaluations of free gingival grafting before implant placement to increase keratinized tissue width in molar regions: A retrospective case series

Timing of keratinized mucosa augmentation and peri-implant outcomes: A systematic review and meta-analysis

PURPOSE

This study aimed to compare different surgical timings for keratinized mucosa (KM) augmentation and assess the impact on peri-implant parameters stability.

METHODS

Electronic searches were conducted through MEDLINE (via PubMed), Scopus, Embase, and Web of Science up to June 13, 2024, which was completed with a manual search. The inclusion criteria focused on randomized and non-randomized human clinical studies that assessed outcomes of KM augmentation, with at least 3-months follow-up. The analysis included changes in KM width over time and several secondary outcomes.

RESULTS

Twenty-five studies satisfied the inclusion criteria. The studies included 855 patients and 1588 implants. The KM width significantly increased after surgery, regardless of the time or method of intervention (MD: 5.17, 95% CI: 4.59, 5.75, p<0.001). The second-stage surgery, particularly with the use of autogenous graft, indicated the lowest reduction in KM width up to 3 months after surgery, while a significant shrinkage was found when the augmentation was performed post-restoratively.

CONCLUSION

The evidence suggests that second-stage surgery is acceptable for KM augmentation, whereas the post-restorative phase is generally not the primary option. In cases where suboptimal soft tissue conditions are detected, it is advisable to either undertake KM augmentation or refer the patient for additional assessment before proceeding with the delivery of the restoration. Due to limited data, it is not possible to come to a definitive conclusion about the other surgical phases.

Effect of free gingival graft dimension on postsurgical shrinkage in posterior implant placement: A prospective parallel cohort study

STATEMENT OF PROBLEM

The impact of free gingival graft (FGG) dimensions on the postsurgical shrinkage of keratinized tissue width (KTW) and surface area in posterior implant sites is unclear. Standardized assessments of how graft dimensions influence KTW and surface area shrinkage rates over a 6-month period after FGG are lacking.

PURPOSE

The purpose of this prospective parallel cohort study was to examine the impact of the graft dimensions on the postsurgical shrinkage of KTW and surface area over a 6-month follow-up period after FGG in the posterior regions.

MATERIAL AND METHODS

Thirty partially edentulous participants with insufficient buccal KTW in the posterior regions were recruited. Before implant placement, participants received FGG procedures and were categorized into single-tooth and dual-tooth groups according to the range of recipient area. Intraoral scanning was performed before and after FGG and at subsequent follow-ups for 6 months. The KTW and surface area shrinkage rates of the grafted area were calculated and statistically analyzed by using the Student t test and ANOVA, and Bonferroni post hoc tests were performed to compare the shrinkage rate of KTW at various edentulous sites (α=.05).

RESULTS

The mean ±standard deviation KTW shrinkage rate was 18.84 ±5.11% over 6 months postoperatively, and the mean ±standard deviation SA shrinkage rate was 21.53 ±5.70%. The dual-tooth group had a statistically significantly higher KTW shrinkage rate (28.42 ±2.46%) when the second molar edentulous sites were involved (P<.05). Differences in surface area shrinkage rates between the single-tooth and dual-tooth groups over 6 months were statistically similar (P=.239). However, grafts in the second molar area exhibited significantly higher surface area shrinkage rates compared with those at the premolar and first molar areas (P<.001).

CONCLUSIONS

The dimension of free gingival graft tissues did not significantly affect surface area shrinkage rates, and a mean 25% shrinkage rate occurred in the second molar areas.

Dimensional changes in free gingival grafts at implant sites in the reconstructed mandible: a retrospective study

OBJECTIVE

To evaluate the dimensional changes in free gingival grafts (FGG) at implant sites in mandibular reconstruction patients.

METHODS

Patients who received FGG 4 months after implant placement in the reconstructed mandible with no keratinized mucosa (KM) present were invited for re-examination after 36.7 ± 16.8 months (3.06 ± 1.4 years). Immediately after graft extraction (T0), graft width (GW), graft length (GL), graft thickness (GT), graft dimension (GD), and vertical bone height were documented. Re-examination (T1) included clinical examinations (GW, GL, GD, peri-implant probing depths, and modified Sulcus Bleeding Index), radiographic examination (marginal bone level), and medical chart review.

RESULTS

Twenty patients and 62 implants (47 in fibula flaps and 15 in iliac flaps) were included. A significant decrease in GW (51.8%), GL (19.2%), and GD (60.2%), were found between T0 and T1 (p < .001). The univariate analysis showed that GW change was not significantly associated with reconstruction technique, baseline GL, baseline GT, baseline GD, implant location, or type of prosthesis. Implant survival rate of 100% was observed at follow-up.

CONCLUSIONS

Within the limitations of the study, free gingival grafts at implant sites in the reconstructed mandible undergo dimensional change that result in a reduction of approximately 60% of the original graft dimension. Graft width decreased over 50%.

CLINICAL RELEVANCE

FGG is the standard of care intervention for increasing the amount of KM around implants. This study was the first to evaluate the dimensional change in FGG at implant sites in mandibular reconstruction patients after a medium-term follow-up.

CLINICAL TRIAL REGISTRATION

Clinical trial registration is not applicable as this study comprehends a retrospective analysis.

Associations between the keratinized mucosa width and the underlying alveolar bone dimensions at partial edentulous molar sites: a retrospective cross-sectional study

BACKGROUND

The assessment of hard and soft tissue at edentulous sites is important for subsequent implant treatment design. The aim of the present study was to explore the associations between the keratinized mucosa width (KMW) and the underlying alveolar bone dimensions at partial edentulous molar sites.

METHODS

In this retrospective study, a total of 110 patients with at least one missing molar were selected. The buccal KMW of the edentulous molar sites was evaluated. Cone-beam computed tomography scans were collected, and the height discrepancy between the alveolar crest and the buccal bone plate (HC-B) as well as the alveolar bone height (ABH) were measured. The KMW was compared among the HC-B and ABH groups at both maxillary and mandibular sites. Linear regression and generalized estimation equations (GEEs) were used to explore the associations between the KMW and alveolar bone dimensions at α = 0.05.

RESULTS

Among the 110 patients, 158 edentulous molar sites were analyzed. The average HC-B and ABH were significantly lower at the maxillary sites (1.26 ± 1.62 mm, 11.62 ± 3.94 mm) than at the mandibular sites (3.67 ± 2.85 mm, 14.91 ± 3.01 mm, p < 0.001). The KMW was significantly lower at sites with HC-B > 2 mm than at sites with HC-B ≤ 2 mm both in the maxilla and mandible (p < 0.001). No significant differences were found between the KMW at sites with ABH < 10 mm and sites with ABH ≥ 10 mm (p > 0.05). Linear regression and GEEs analyses revealed that the HC-B was significantly associated with the KMW (B = -0.339, p < 0.001), while the association between the KMW and the ABH was not statistically significant (B = -0.046, p = 0.352).

CONCLUSIONS

The buccal KMW at edentulous molar sites was significantly associated with the HC-B. Alveolar ridges presenting with a sloped configuration were more prone to possess a narrower band of keratinized mucosa. Both hard and soft tissue augmentation should be considered for implant treatment at these sites. The correlations of dynamic changes between the KMW and alveolar bone dimensions after tooth extraction should be further investigated.

Effect of botulinum toxin-A injection applied to the mentalis muscle on free gingival graft operation: A retrospective study

OBJECTIVE

The purpose of this retrospective study was to investigate the effects of Botulinum Toxin-A (BTX-A) injection into the mentalis muscle on the free gingival graft (FGG).

MATERIALS AND METHODS

Forty patients with keratinized gingiva insufficiency and Cairo's RT 2 gingival recession (formerly classified as Miller class III) in their mandibular central incisors were randomly divided into two groups: FGG and FGG + BTX. Plaque index (PI), gingival index (GI), probing pocket depth (PPD), keratinized gingiva width (KGW), attached gingiva width (AGW), clinical attachment level (CAL), gingival thickness (GT), gingival recession amount (GRA), gingival recession width (GRW), and root closure percentage (RCP%) parameters were measured at baseline and at first, third, and sixth months after the operation.

RESULTS

There was no difference in PI, GI, and PPD levels in both groups (p > 0.05). While the change in GT and RCP% levels were found to be statistically significantly higher at FGG + BTX group than FGG group, the change in GRW and CAL levels were statistically significantly lower (p < 0.05).

CONCLUSION

The findings of this study indicate that BTX-A injection applied to the mentalis muscle after FGG operation may have positive effects in terms of KGW, AGW, GT, RCP%, GRW, and CAL parameters.

CLINICAL SIGNIFICANCE

As a result of the fact that BTX-A injection into the mentalis muscle contributed to the nutrition and immobility of FGG, positive developments were obtained in terms of clinical periodontal parameters. BTX-A injection into the mentalis muscle may be an alternative method that increases the success rate of Cairo's RT 2 gingival recession.

Ridge preservation in periodontally compromised molar sockets with and without primary wound closure: A comparative controlled clinical trial

OBJECTIVE

This study aimed to compare hard- and soft-tissue changes after ridge preservation in periodontally compromised molar sockets with and without primary wound closure.

MATERIALS AND METHODS

Forty molars with severe periodontitis requiring extraction were included and allocated to two treatment modalities. After tooth extraction, the sockets were filled with deproteinized bovine bone mineral and covered with a bioabsorbable porcine collagen membrane. Primary wound closure was achieved in the control group, whereas the test group underwent minimally invasive open healing. The dimensions of the bone and soft tissue were recorded at baseline and 6 months.

RESULTS

Over 6 months, the control and test groups had similar mean ridge heights at the center of sockets of 8.59 ± 2.47 mm and 8.47 ± 2.51 mm, respectively. The total volume of the control group increased from 1070.17 to 1713.52 mm3 for a mean gain of 643.35 mm3 , whereas that of the test group increased from 992.51 to 1514.05 mm3 for a mean gain of 521.54 mm3 . Compared with the test group, the control group showed a statistically significant decrease in keratinized tissue width of 1.08 ± 1.63 mm.

CONCLUSIONS

Bone dimensional changes following ridge preservation with and without primary wound closure were comparable. ARP without primary wound closure preserves more keratinized tissue than that with (Chinese Clinical Trial Registry: ChiCTR-ONN-16009433).

Soft tissue phenotype modification impacts on peri-implant stability: a comparative cohort study

OBJECTIVES

Soft tissue phenotype modification (STPM) could be performed to maintain peri-implant health. Therefore, the aim of the study was to analyze tissue alteration around implants following soft tissue phenotype modification during implant uncovering surgery.

MATERIALS AND METHODS

Patients who had STPM (either pouch roll or modified roll technique) during implant second-stage surgery with at least 12-month follow-up were included. Clinical and radiographic parameters including mucosal tissue thickness (MTT), recession (REC), keratinized mucosa width (KMW), probing pocket depth (PPD), marginal bone loss (MBL), emergence profile, and emergence angle were extracted from 2-week, 2-month, and 12-month visits after second-stage surgery.

RESULTS

Twenty-eight patients with 33 implants that fulfilled the inclusion criteria were included. After soft tissue phenotype modification, at 2 weeks, REC was negatively correlated to mean MTT at mid-buccal site (r =  - 0.41, p = 0.018) and borderline correlated at mid-lingual site (r =  - 0.343, p = 0.051). Stable KMW was maintained from 2 weeks to 12 months with minimal shrinkage rate (3 ~ 14%). MBL change was limited (0.24 ~ 0.47 mm) after STPM. All implants had shallow PPD (≤ 3 mm) with the absence of bleeding on probing. Emergence angle at the mesial side, however, was significantly correlated to surgical techniques, which indicated pouch roll technique would have 6.96 degrees more than modified roll technique (p = 0.024).

CONCLUSIONS

Soft tissue phenotype modification, either pouch roll or modified roll technique, during uncovering surgery resulted in favorable clinical outcomes. Thin mucosal tissue thickness and pouch roll technique are the factors related to more recession at 2 weeks. Pouch roll technique could influence the restorative design by having a wide emergence angle at the mesial side.

CLINICAL RELEVANCE

Modified and pouch roll techniques during uncovering surgery were viable methods to yield favorable peri-implant health, while the preciseness of pouch roll technique was required to avoid mucosal recession and inadequate restorative design.

The keratinized mucosa width at partially edentulous molar sites and its associated factors: a pilot study

BACKGROUND

Assessment of the keratinized mucosa width (KMW) at edentulous sites is important for the subsequent implant treatment design. This pilot study aimed to evaluate the characteristics of the KMW at edentulous molar sites and explore the associated factors.

METHODS

A total of 150 patients with 222 edentulous molar sites were included. The buccal KMW of the edentulous molar sites was measured during implant treatment planning. Potentially associated factors, including age, sex, smoking status, location, reasons for tooth loss/extraction, gingival phenotype (GP) and keratinized gingival width (KGW) of the adjacent teeth, were collected and analyzed. The Shapiro‒Wilk test, Student's t test, one-way ANOVA, generalized estimation equations (GEEs) and linear regression analysis were used for data analysis at α = 0.05.

RESULTS

The buccal KMW at edentulous molar sites was 3.97 ± 2.06 mm, and 41.9% of sites presented with KMW < 4 mm. The mean KMWs of the maxillary sites were significantly higher than that those of the mandibular sites (4.96 ± 2.05 mm vs. 3.41 ± 1.85 mm, respectively). In total, 54.7%, 46.5%, 29.8%, and 0.0% of mandibular first and second molar sites and maxillary first and second molar sites, respectively, displayed a KMW of < 4 mm. Statistically significant linear correlations were found between KMW and GP (r = 0.161, p = 0.025) and between KMW and KGW of the adjacent teeth (r = 0.161, p = 0.023), while other factors were found to have no significant association.

CONCLUSION

Within the limitations of the present study, the KMW at edentulous molar site was related to the location of molar tooth loss/extraction. The GP and KGW of the adjacent teeth of edentulous molar sites were also associated with their KMW, which was probably attributed to the continuity of the adjacent soft tissue.

Assessment of soft and hard tissue characteristics of ridge preservation at molar extraction sites with severe periodontitis: a randomized controlled trial

Background

Changes in alveolar bone dimension after tooth extraction may affect placement of the subsequent implant, resulting in ridge deficiency that can adversely impact long-term implant stability or aesthetics. Alveolar ridge preservation (ARP) was effective in reducing the amount of ridge resorption following tooth extraction. There is sparse evidence regarding the benefit of ARP at periodontally compromised molar extraction sockets. This study will be a randomized trial to assess the soft tissue contour, radiographical, and histological changes of ARP at molar extraction sites in order to compare severe periodontitis cases with natural healing results and determine the most beneficial and least traumatic clinical treatment for such patients.

Methods

This research is designed as a two-group parallel randomized controlled trial. The total number of tooth extraction sites will be 70 after calculation with power analysis. Teeth will be randomly assigned to two groups with the test group conducting ridge preservation and the control group healing naturally. Periodontal examination, cone beam-computed tomography (CBCT) data, and stereolithographic (STL) files obtained by intraoral scanning will be collected through the follow-up period, and bone biopsy samples would be obtained during implant surgery. The primary outcomes are the vertical and horizontal change of alveolar ridge measured on CBCT images, soft tissue contour changes evaluated by superimposing the digital impressions, alterations of mucosa thickness (as measured by superimposing the CBCT data and STL files), histological features of implant sites and periodontal parameter changes. The secondary outcomes are patient-reported post-operative reaction and conditions of simultaneous bone graft or sinus lifting procedures during implantation.

Discussion

This study will provide information about hard and soft tissue dimension changes and histomorphology evaluation following ARP and natural healing in periodontally compromised molar sites, which may contribute to complement the missing information of ARP at periodontally compromised molar extraction sockets.

Trial registration

Chinese Clinical Trial Register (ChiCTR) ChiCTR2200056335. Registered on February 4, 2022, Version 1.0.