Immunohistochemical study during healing of free palatal mucosa grafts on plastic-embedded samples

This immunohistochemical study describes changes in the histology and in the distribution of the basement membrane components laminin and collagen IV as well as of the cytokeratins (CK)1/2/10/11, CK5/6, CK13, CK14, CK17, CK19 during the take of free split mucosa (epithelial and connective tissue) transplants in humans up to 36 months post-operative. Histology showed a flattening of the epithelial layer within the first 2 weeks after grafting, followed initially by an increase (25-30 layers, week 6) and later on by a decrease of cell layers in the epithelium (15-20 layers, week 20). From that time onwards, clear stratification and reteridges as signs of differentiation were present. Up to day 14 of graft take, the linear staining patterns for laminin and collagen IV were interrupted, which was not observed at any later stage. During this early interval CK5/6, CK1/2/10/11, CK14 and CK17 were expressed in all epithelial layers. The reactions for CK5/6 and CK1/2/10/11 were less intensive. At 6 weeks, CK1/2/10/11 stained the intermediate and superficial layers, being consistent with findings after longer graft take. CK5/6 reacted in the basal and intermediate cell layers, and CK13, CK14 and CK17 reacted in all layers. In the following period up to week 20, CK5/6 were found in the parabasal cells of the intermediate cell layers and the basal cells. CK14 staining was confined to these cell layers too, but also showed some reaction in the superficial layers. CK13 and CK17 were still bound to all layers. At 7 months post-operative, CK5/6 and CK14 were seen in their typical localisation in the basal cell layer and the parabasal cells of the intermediate layers, CK17 was seen mainly in the intermediate layer and CK13 was seen in focal areas of all layers. Anti-CK19 reacted only with single basal and parabasal cells up to week 20. These results suggest that during healing of mucosal autografts there is a sequence of changes in the expression of cell biological differentiation markers that may involve an epithelio-connective tissue interaction before the typical patterns for the donor side were observed again on the gingiva or mucosa of the hard palate.     

Oral flurbiprofen spray for mucosal graft harvesting at the palatal area: A randomized placebo‐controlled study

1 Background

Flurbiprofen which is a non‐steroidal anti‐inflammatory drug (NSAID), has been safely used for the control of postoperative patient's morbidity after periodontal plastic surgeries requiring palatal graft harvesting, but there is little information on the efficacy of topical use. The aim of the study was to evaluate whether patient pain perception was reduced and patient morbidity was improved by using oral spray of flurbiprofen after palatal graft harvesting.

2 Methods

Forty‐eight patients (21 males and 27 females), scheduled for subepithelial connective tissue graft (SCTG) and free gingival graft (FGG) requiring periodontal plastic surgeries were selected. The patients were randomly assigned to each group and used oral spray of flurbiprofen or placebo three times a day for a week. The palatal donor area was evaluated at 1, 3, 7, 14, 21, 28, 42, and 56‐day follow‐up after the surgery for postoperative pain, patients’ discomfort, complete epithelialization, changes in dietary habits, burning sensation, color match, the amount of systemic analgesic consumption and the presence of delayed bleeding. Wound healing scores were recorded at 14‐day follow up.

3 Results

The prevalance of complete epithelialization was significantly higher in the placebo‐FGG group than flurbiprofen‐FGG group at 21 days postoperatively (P < 0.05), while there was no significant alteration for both flurbiprofen‐SCTG and placebo‐SCTG groups at any follow‐up periods. In flurbiprofen‐FGG group, significant improvements were observed for postoperative pain, patients’ discomfort and burning sensation at 14 days postoperatively (P < 0.05).

4 Conclusion

Oral flurbiprofen spray reduces patient's morbidity, however it might have negative effects on epithelialization of secondary wound healing after FGG operations.     

Ultrastructure of squamous epithelium during wound healing in palatal mucosa of guinea pigs

The ultrastructure of the epithelium of wounded guinea pig palate was studied. Twenty-four biopsies (animals) were used. Biopsies were taken 18, 48, 96, and 120 h after wounding. Essential changes in epithelial cell structure in response to wounding were as follows: microfilaments, suggested to represent actin-containing filaments, became evident in the cortical cytoplasmic zone. Micro tubules prevailed in the peripheral cytoplasm. Tonofilament bundles assumed the character of short tufts or delicate bundles and. the amount of non-bundled tonofilaments was increased. These observations suggest changes in the cytoskeletal/contractile system facilitating cell motility. The structure of lysosomal profiles indicates an enhanced phagocytic capability. Influence of fixation on preservation of non-membrane-bound organelles is suggested based on comparable morphometric data.     

The effect of non-resorbable membrane on buccal bone healing at an immediate implant site: an experimental study in dogs

Objective: For successful implant treatment in the esthetic area, stable hard tissue and soft tissue are very important. At the buccal side without buccal bone defects, prophylactic guided bone regeneration (GBR) with bone substitute was frequently used for achieving thick buccal bone. The aim of this study was to evaluate the effect of GBR using a non‐resorbable membrane in an immediate implant site without bone defects. Material and methods: Immediate implants were placed into the mandibles of four mongrel dogs. In the experimental group (TM group), a non‐resorbable membrane was placed and fixed onto the buccal bone plate around the implant. In the control group, the implants were placed without membrane coverage. After 12 weeks, the dogs were sacrificed and histological specimens were prepared. The vertical distances from the smooth–rough surface interface (SRI) to the gingiva, the first‐bone contact, and the bone crest were measured on the buccal and lingual sides. The horizontal thicknesses of the gingiva and bone at 0, 1, 2, and 3 mm below the SRI were measured. Results: In the TM group, first‐bone contact on the buccal side was more coronally positioned approximately 0.8 mm than the control group (P=0.041). The buccal bone thickness of the TM group was well preserved and there was no difference between the buccal and lingual sides. Comparing the control group, implants of the TM group had 1 mm thicker buccal bone (P=0.0051 at bone 1 mm level, P=0.002 at bone 2 mm level). In the control group, buccal bone loss was observed and buccal bone was about 1 mm thinner than the lingual bone (P<0.05). Conclusions: GBR with a non‐resorbable membrane and no bone graft substitute could help to preserve buccal bone thickness on the immediate implant site without defects. To cite this article:
Park S‐Y, Kye S‐B, Yang S‐M, Shin S‐Y. The effect of non‐resorbable membrane on buccal bone healing at an immediate implant site: an experimental study in dogs.
Clin. Oral Impl. Res. 22 , 2011; 289–294.
doi: 10.1111/j.1600‐0501.2010.01995.x     

Low‐intensity laser for harvesting palatal graft for the treatment of gingival recession: A systematic review

The aim of the present study was to assess the efficacy of low‐intensity laser therapy (LILT) for harvesting palatal connective tissue graft (PCTG) in the treatment of gingival recession. Databases were searched up to May 2018. The addressed focused question was: Is adjunctive LILT effective in the healing of donor palatine area after harvesting PCTG? Screening of the initially identified studies resulted in four clinical studies. All studies showed that LILT was effective in improving clinical outcomes, such as tissue thickness, postoperative discomfort, remaining wound area, and visual analog score at follow up. Upon comparison with the control group, two studies showed significantly greater improvements in the clinical parameters and patient‐centered outcomes for LILT than control groups at follow up. Due to the low number of included clinical studies, it remains debatable whether LILT improves clinical and patient‐centered outcomes of PCTG procedures. Further randomized controlled trials are needed to evaluate the outcomes of LILT on the healing of donor palatine area after harvesting PCTG     

Cell junctions in squamous epithelium during wound healing in palatal mucosa of guinea pigs

The nature and distribution of cell junctions of the epithelium of wounded guinea pig palate were .studied. Biopsies, 32 in total, were taken 13, 48, 96, and 120 h after wounding. Desmosomes were present in the wound epithelium throughout the observation period. Primitive desmosomes, indicating de novo formation of desmosomes, were observed at the front of advanced migratory lips (48 h) and in the central region and the wound epithelium after bridging (96 and 120 h). Similarly, de novo formed hemidesmosomes were seen. They occurred along epithelial cell membranes exposed to the fibrinous wound exudate during the migratory lip stages (18 and 48 h) and after epithelial bridging. The observations .suggest that wounding induced changes in the mechanical properties of the tissue. Gap junctions were present in migrating epithelium preferably at the stem of the lips and in the epithelium after bridging, which suggests their participation in regulation of the epithelial cell differentiation. Tight junctions, capable of acting as seals, were absent or fragmentary at best. A relative decrease in the volume density of intercellular spaces in migrating epithelium as compared to intact epithelium, suggests an in vivo tissue reaction.     

Effect of local antimicrobial agents on excisional palatal wound healing: a clinical and histomorphometric study in rats

AIM: To assess the effect of topically applied antimicrobial agents on palatal excisional wound in rats. MATERIALS AND METHODS: Excisional wounds, 5 mm in diameter, were made in the centre of the palate of 125 Wistar male rats. In four experimental groups, chlorhexidine digluconate (CHX) 0.12% solution, 1% CHX gel, phenolic compounds solution (Listerine), amine/stannous fluoride solution (Meridol) and saline solution as a control group were applied daily for 1 min. The wound area was measured photographically and the epithelialization rate was determined histologically at 3, 7, 14 and 21 days post-surgery. RESULTS: The mean wound area and mean distance between the epithelial margins decreased significantly with time (p<0.001) in experimental and control groups, with the greatest wound area reduction and rate of epithelialization on day 14. A significantly superior rate of wound epithelialization (p=0.03) was presented following use of 1% CHX gel and Listerine and a comparatively inferior one when the Meridol solution was applied. CONCLUSIONS: Each tested antimicrobial agent when applied on an excisional wound with epithelial and connective tissue deficiency did not have a negative effect on the rate of wound closure. The best results were achieved with 1%CHX gel and Listerine.     

Effect of surface contamination on osseointegration of dental implants surrounded by circumferential bone defects

Objective: This study was designed to evaluate the effect of surface contamination on osseointegration of dental implants surrounded by a circumferential bone defect and to compare osseointegration around Osseotite® with that around Nanotite^? implants. Materials and methods: The premolars on both sides of the mandible in four beagle dogs were extracted. Following 4 months healing, two Nanotite^? implants and two Osseotite® implants were partially inserted in the left side of each mandible. Some threads protruded from the tissues into the oral cavity. Following a 5 week healing period, the implants were removed and the contaminated part of each implant was cleaned. They were then installed to the full implant length on the contra lateral side of the mandibles. The coronal 5 mm of each implant was surrounded by 1 mm circumferential bone defect. Following 12 weeks of healing period, the dogs were sacrificed and biopsies were obtained. Ground sections were prepared for histomorphometric analysis. Results: All implants were associated with direct bone‐to‐implant contact on the portion of the implant surface contaminated previously and surrounded by bone defect. Nanotite^? implants performed better than Osseotite® implants. Conclusions: The results demonstrated that implant surfaces, which were contaminated previously and were surrounded by bone defects, can osseointegrate. To cite this article:
Mohamed S, Polyzois I, Renvert S, Claffey N. Effect of surface contamination on osseointegration of dental implants surrounded by circumferential bone defects. Clin. Oral Impl. Res. 21 , 2010; 513–519.
doi: 10.1111/j.1600‐0501.2010.01913.x     

Therapeutic effect of topical ozonated oil on the epithelial healing of palatal wound sites: a planimetrical and cytological study

Aim: To evaluate the effect of ozonated oil on palatal wounds. Methods: Eighteen patients were randomized and allocated to either the ozone group (n = 8) or control (n = 10) group. Free gingival graft surgery was performed, and post‐harvested palatal wounds were treated with either 2 mL ozonated oil or control oil daily for 1 week. A planimetrical analysis analyzed the digital image for the wound sizes and shape factor at baseline, at 24 h, and days 5, 7, 14, 21, and 28, postoperatively. A cytological analysis used the keratinization and superficial cell indices at baseline, 24 h, and days 3, 7, 14, and 21 and the second and third months, postoperatively. Results: Planimetrical results showed a significant (P ≤ 0.05) improvement in wound size on days 5, 7, 14, 21, and 28, postoperatively, in the ozone group compared to the control group. Cytological results showed a significant (P ≤ 0.001) improvement in epithelial healing on days 7, 14, and 21, and the second and third months, postoperatively, after the application of ozonated oil compared to control oil. Conclusion: Our results showed significant improvement in wound size and epithelial healing after topical ozonated oil application compared to control oil on palatal wounds.     

Innocent until proven guilty: mechanisms and roles of Streptococcus–Candida interactions in oral health and disease

Candida albicans and streptococci of the mitis group colonize the oral cavities of the majority of healthy humans. While C. albicans is considered an opportunistic pathogen, streptococci of this group are broadly considered avirulent or even beneficial organisms. However, recent evidence suggests that multi‐species biofilms with these organisms may play detrimental roles in host homeostasis and may promote infection. In this review we summarize the literature on molecular interactions between members of this streptococcal group and C. albicans, with emphasis on their potential role in the pathogenesis of opportunistic oral mucosal infections.     

Lymphoid susceptibility to the Aggregatibacter actinomycetemcomitans cytolethal distending toxin is dependent upon baseline levels of the signaling lipid,phosphatidylinositol‐3,4,5‐triphosphate

The Aggregatibacter actinomycetemcomitans cytolethal distending toxin (Cdt) induces G2 arrest and apoptosis in lymphocytes and other cell types. We have shown that the active subunit, CdtB, exhibits phosphatidylinositol‐3,4,5‐triphosphate (PIP3) phosphatase activity and depletes lymphoid cells of PIP3. Hence we propose that Cdt toxicity results from depletion of this signaling lipid and perturbation of phosphatidylinositol‐3‐kinase (PI‐3K)/PIP3/Akt signaling. We have now focused on the relationship between cell susceptibility to CdtB and differences in the status of baseline PIP3 levels. Our studies demonstrate that the baseline level of PIP3, and likely the dependence of cells on steady‐state activity of the PI‐3K signaling pathway for growth and survival, influence cell susceptibility to the toxic effects of Cdt. Jurkat cells with known defects in both PIP3 degradative enzymes, PTEN and SHIP1, not only contain high baseline levels of PIP3, pAkt, and pGSK3β, but also exhibit high sensitivity to Cdt. In contrast, HUT78 cells, with no known defects in this pathway, contain low levels of PIP3, pAkt, and pGSK3β and likely minimal dependence on the PI‐3K signaling pathway for growth and survival, and exhibit reduced susceptibility to Cdt. These differences in susceptibility to Cdt cannot be explained by differential toxin binding or internalization of the active subunit. Indeed, we now demonstrate that Jurkat and HUT78 cells bind toxin at comparable levels and internalize relatively equal amounts of CdtB. The relevance of these observations to the mode of action of Cdt and its potential role as a virulence factor is discussed.     

Effect of topically applied hyaluronic acid on pain and palatal epithelial wound healing: An examiner‐masked,randomized, controlled clinical trial

1 Background

This study aims to evaluate the effects of two different concentrations of topical hyaluronic acid (HA) on postoperative patient discomfort and wound healing of palatal donor sites after free gingival graft (FGG) surgery.

2 Methods

Thirty‐six patients requiring FGG were randomly assigned into three groups in an examiner‐masked, randomized, controlled clinical trial. After harvesting palatal grafts, 0.2% and 0.8% HA gels were used in test groups 1 and 2, respectively. Gels were applied on donor sites and protected with periodontal dressing in the test groups, whereas the wound was covered only with periodontal dressing in the control group. On days 3, 7, 14, and 21, pain and burning sensation were recorded using a visual analog scale (VAS) as well as other parameters such as complete epithelization (CE) and color match on days 3, 7, 14, 21, and 42.

3 Results

Test groups experienced less pain than the control group on days 3 and 7 (P <0.001 and P <0.001, respectively). Mean VAS score for burning sensation was higher in the control group on day 3 compared with test groups 1 and 2 (P = 0.03 and P = 0.02, respectively). CE in all patients was achieved on day 21 in both test groups, whereas it was achieved on day 42 in the control group. The test groups showed higher color match scores than the control group on days 21 (P <0.001 and P <0.001, respectively) and 42 (P = 0.004 and P = 0.002, respectively).

4 Conclusion

Topical application of HA exhibits positive impact on postoperative pain and burning sensation, and accelerates palatal wound healing in terms of epithelization and color match.