Histological and histomorphometric study of human palatal mucosa: Implications for connective tissue graft harvesting

Comparison of the Histological Structure of an Anterior as well as a Posterior Biopsy From the Human Palate: A Comparative Study

AIM

To compare the histological structure of biopsies from the anterior and posterior regions of the human palate in order to gain insights into potential differences of soft tissue harvesting sites.

METHODS

This comparative study involved 20 participants, from each of whom four samples from the palatal mucosa were collected. The biopsies were histologically processed and subsequently analysed. The thickness of the epithelium, lamina propria, and the length of the rete pegs were measured using a microscope. In addition, parameters such as collagen fibres, elastic fibres, elastic connective tissue, loose connective tissue and the background were measured.

RESULTS

The mean epithelial thickness was 0.42 mm anteriorly and 0.37 mm posteriorly. The mean thickness of the lamina propria was 0.81 mm anteriorly and 0.85 mm posteriorly. Within the region of interest, collagen fibres were significantly less abundant anteriorly than posteriorly (p = 0.016). The loose connective tissue showed a significantly higher occurrence in the anterior compared with the posterior sampling site (p = 0.004).

CONCLUSION

This trial indicates no differences in terms of the thickness of the lamina propria. There was a higher concentration of collagen fibres and a lower concentration of loose connective tissue in the posterior region of the palate.

Microsurgical Semilunar Bilaminar Technique Halts Progression of Marginal Tissue Recession by Soft Tissue Phenotypic Modification-A Case Report With 3-Year Follow-Up

Phenotype modification therapy using the novel semilunar flap with xenogeneic collagen matrix improves gingival phenotype, root coverage and increased keratinized tissue width. It also halts the progression of recession, enhances tissue resilience and improved plaque control sustainable over 3 years. Collagen matrix avoids second site surgery and hence less morbidity.

Histological Analysis of Oral Tissue Grafting: A Focus on Donor Site Selection

The science of dental tissue grafting is evolving, with an increased understanding of factors influencing graft behavior. Despite the widespread clinical use of soft tissue grafts, the histological characteristics of different gingival harvesting sites are still underexplored. This study aimed to fill this gap by analyzing 50 tissue samples harvested from 25 patients across three sites: the hard palate, maxillary tuberosity, and palatal rugae. Each sample underwent thorough histological and histomorphometric analysis. Conventional statistical analysis was performed using SPSS, while predictive modeling was conducted with RapidMiner Studio. The study identified significant histological differences among the graft sites, with notable variations in total graft height, epithelial height, and interdigitation perimeter. These findings underscore the importance of donor site selection in influencing graft success. Pair plots and principal component analysis (PCA) further highlighted the distinct histological features of each tissue type. The random forest classifier identified total graft height, epithelial height, and perimeter as the most influential factors in predicting graft site behavior. This study offers valuable insights into the histological characteristics of soft tissue grafts, potentially leading to more predictable clinical outcomes.

Management of hyperplastic tissue response following connective tissue grafting

OBJECTIVE

While connective tissue graft shrinkage is a well-documented post-transplantation reaction, there is a literature gap concerning hyperplastic tissue response. Despite its infrequent occurrence, investigation is warranted due to its capacity to compromise esthetics, disrupt lip dynamics, and promote food retention. Moreover, efforts to mitigate hyperplastic tissue response often prove challenging, and there is a potential risk of exacerbating gingival tissue rebound.

CLINICAL CONSIDERATIONS

This report presents a potential solution to managing tissue overgrowth after connective tissue grafting in five clinical cases. The patients underwent corrective surgery involving internal excision of excessive tissue while preserving the overlying mucosa. The surgical approach was tailored to excise hyperplastic tissue with minimal trauma, aiming to optimize esthetic outcomes. Subsequent follow-up assessments spanning 1-5 years demonstrated stable results, with no indications of relapse or recurrence of tissue overgrowth.

CONCLUSIONS

Within the limitations of this case series, surgical internal excision holds promise as a viable treatment modality for addressing post-transplantation hyperplastic tissue response.

CLINICAL SIGNIFICANCE

This case series addresses the challenge of uncontrolled tissue overgrowth following connective tissue grafting, a concern for which previous attempts have proven unsuccessful. Internal in-toto excision emerges as a promising approach for effectively eliminating overgrown tissue, offering potential advancements in the clinical management of this complication.

Histological assessment of a novel de-epithelialization method for connective tissue grafts harvested from the palate. An experimental study in cadavers

OBJECTIVES

This study aims to compare the histological outcomes of three distinct de-epithelialization methods used in (connective tissue grafts) CTG harvested from the palate.

MATERIALS AND METHODS

An experimental study using nine cadaver head specimens was carried out to compare 3 different de-epithelialization techniques for CTG. Eighteen samples were randomly allocated to three study groups: bone scraper, diamond bur and extraoral removal with a scalpel. The main outcome variable was the graft surface percentage without epithelium remains. Additionally, the time employed, and the graft thickness were also measured.

RESULTS

Sixteen CTGs were analyzed. The extraoral scalpel group presented a total surface area with no epithelium of 58.84% (22.68) and a mean de-epithelialization time of 3.7 min; the intraoral diamond bur group had 88.24% (41.3) of the surface with no epithelium and took 1.455 min, and the intraoral bone scraper showed 97.98% (5.99) of surface without epithelium and a mean time of 0.815 min (P < 0.05). Histological analysis showed significant differences between the bone scraper and the extraoral group (P = 0.009).

CONCLUSION

The de-epithelialization technique with a bone scraper seems to be the most effective and fastest de-epithelialization technique for CTG. These findings need to be confirmed in future clinical studies with larger samples.

CLINICAL RELEVANCE

The use of bone scrapers, could be a simple, effective and fast technique to de-epithelialize connective tissue grafts harvested from the palatal area for both novice and experienced surgeons.

Treatment of Multiple RT1 Gingival Recessions Using a Coronally Advanced Flap Associated with L-PRF or Subgingival Connective Tissue Graft from Maxillary Tuberosity: A Randomized, Controlled Clinical Trial

The goal of plastic periodontal surgery is to obtain complete root coverage, increasing gingival thickness (GT), a positive prognostic factor for gingival margin stability over time. The aim of this study was to compare the effectiveness of the Coronally Advanced Flap (CAF) in RT1 (GR; gingival recession with no loss of interproximal attachment) when associated with a connective tissue graft from the maxillary tuberosity (tCTG) or with leukocyte and platelet-rich fibrin (L-PRF) membranes in obtaining root coverage and increasing the thickness and width of the keratinized tissue, along with aesthetic improvement, taking into account a number of patient-related outcomes. Thirty patients with two adjacent RT1 GRs (GRs with no loss of interproximal attachment) were each treated using CAF associated with tCTG (15 patients) or L-PRF. The main outcome was a GT increase; secondary outcomes were keratinized tissue width (KT), gingival recession (GR), probing depth (PD), clinical attachment level (CAL), root coverage percentage (RC%), complete root coverage (CRC), and root coverage esthetic score (RES). Patient-reported outcomes were discomfort (D), dentine hypersensitivity (DH), patient-related esthetic score (PRES), and overall treatment satisfaction (OTS). After 12 months, clinical and patient-reported parameters did not show significant differences between groups, with the only exception being a GT gain, which was significantly greater in the CAF + tCTG group. Our results showed that both techniques were effective in treating RT1 GRs, with comparable patient-related outcomes. However, the use of tCTG produces significantly thicker tissue, covering the exposed root surface.

Long-term stability of gingival margin and periodontal soft-tissue phenotype achieved after mucogingival therapy: A systematic review

BACKGROUND

The aim of this systematic review was two-fold: (i) to evaluate the long-term (≥5 years) stability of the gingival margin position, keratinized tissue width (KTW) and gingival thickness (GT) in sites that underwent root coverage (RC) or gingival augmentation (GA); and (ii) to assess the influence of different local variables on the long-term stability of dental and gingival tissues.

MATERIALS AND METHODS

Randomized controlled trials (RCTs) and non-RCTs reporting short-term (i.e., 6-12 months after baseline surgical intervention) and long-term (≥5 years) follow-up data after surgical treatment of adult patients presenting single or multiple mucogingival deformities, defined as sites presenting gingival recession defects (GRDs) and/or (KTW) deficiency (i.e., <2 mm), were considered eligible for inclusion. MEDLINE-PubMed, EMBASE and Cochrane Central Register of Controlled Trials databases were searched for articles published up to 15 May 2023. Mixed-effects multiple linear regression was used to assess the association between KTW, type of surgical procedure and time (i.e., independent variables) on the stability of the gingival margin in sites that received RC or GA therapy.

RESULTS

Of the 2569 potentially eligible records, 41 (reporting 40 studies) met the eligibility criteria. Graphical estimates including data from all RC procedures found an upward trend in recession depth (RD) increase over time. Conversely, it was observed that in 63.63% of RC studies and in 59.32% of RC treatment arms KTW increased over time, particularly in sites treated with subepithelial connective tissue grafts (SCTGs). Conversely, sites that underwent GA procedures generally exhibited an overall reduction of KTW over time. However, sites treated with free gingival grafts (FGGs) showed a decrease in RD after 10 years of follow-up. Three main findings derived from the pooled estimates were identified: (i) Gingival margin stability was associated with the amount of KTW present during short-term assessment (i.e. the greater the KTW at 6-12 months after treatment, the more stable the gingival margin). (ii) The use of autogenous soft-tissue grafts was associated with lower RD increase over time. (iii) Treatment approaches that contribute to the three-dimensional enhancement of the gingival phenotype, as clearly demonstrated by FGG, were associated with gingival margin stability.

CONCLUSIONS

The extent of apical migration of the gingival margin appears to be directly related to the amount of KTW and GT upon tissue maturation. Interventions involving the use of autogenous grafts, either SCTG or FGG, are associated with greater short-term KTW gain and lower RD increase over time.

Differential molecular profiles and associated functionalities characterize connective tissue grafts obtained at different locations and depths in the human palate

The present study aimed to assess the molecular profiles of subepithelial connective tissue grafts (CTGs) obtained at different locations and depths in the human palate. Sixty-four CTGs belonging to anterior deep (AD), anterior superficial (AS), posterior deep (PD), and posterior superficial (PS) groups were subjected to RNA-Sequencing and their transcriptomes were analyzed computationally. Functional correlations characterizing the CTG groups were validated by cell biological experiments using primary human palatal fibroblasts (HPFs) extracted from the CTGs. A clearly more pronounced location-dependent than depth-dependent difference between the grafts, with a minimal number of genes (4) showing no dependence on the location, was revealed. Epithelial, endothelial, and monocytic cell migration was strongly (P < 0.001) potentiated by AD- and PS-HPFs. Moreover, significantly increased expression of genes encoding C-C and C-X-C motif chemokine ligands as well as significantly (P < 0.01) activated p38 signaling suggested immunomodulatory phenotype for AD- and PS-HPFs. Increased growth factor gene expression and significantly activated (P < 0.001) Erk and Akt signaling in HPFs originating from A-CTGs implied their involvement in cell survival, proliferation, and motility. Prominent collagen-rich expression profile contributing to high mechanical stability, increased osteogenesis-related gene expression, and strongly activated (P < 0.001) Smad1/5/8 signaling characterized HPFs originating from P-CTGs. The present data indicate that in humans, differences between palatal CTGs harvested from different locations and depths appear to be location- rather than depth-dependent. Our findings provide the basis for future personalization of the therapeutic strategy by selecting an optimal graft type depending on the clinical indications.

Pre-operative, chair-side Zn-containing surgical stents affect morbidity and wound healing after free gingival graft harvesting: a randomized clinical trial

OBJECTIVE

To compare a pre-operatively, chair-side made, zinc-containing surgical stent (ZN) and suturing of a gelatin-based hemostatic agent (HA) on palatal wound healing and patient morbidity after free gingival graft surgery (FGG).

MATERIALS AND METHODS

Sixty patients requiring FGG were randomly divided into two groups to receive either a ZN or a sterile HA sutured on the surgical area. Patients were evaluated at 1st, 3rd, 7th, 14th, 28th, and 56th days following surgery. Overall surgical time, donor site surgical time, postoperative pain (PP), delayed bleeding (DB), changes in dietary habits (DH), burning sensation (BS), completion of re-epithelialization (CE), and patients' discomfort (PD) were evaluated.

RESULTS

Donor site surgical time, PP, DB, DH, BS were statistically significantly lower in the ZN group together with faster completion of re-epithelialization compared to the HA group.

CONCLUSION

Pre-operatively, chair-side made, zinc-containing surgical stents provided significant benefits for wound healing parameters and patients' postoperative morbidity after FGG harvesting.

CLINICAL RELEVANCE

The results show that using Zn-containing palatal stent after free gingival graft surgery significantly reduces pain and patient morbidity during the postoperative period.