Periodontal healing following open debridement flap procedures. II. Histologic observations

Post-Operative Bleeding Complications in a Periodontitis Patient Testing Positive for COVID-19

Recent scientific evidence states that a subset of COVID-19 patients may have a risk of increased bleeding tendency. This case report presents a healthy 38-year-old woman with generalized stage III, grade C periodontitis with an abnormal post-operative blood clot formation who tested positive for COVID-19 after a standard periodontal surgery. Previously, two periodontal surgeries proceeded without any complications and were considered standard. On day one after the third periodontal surgery the patient had no complaints. On day two the patient reported excess bleeding in the oral cavity from the operated area simultaneously with fever and loss of taste. On day three the patient was seen in our clinic; general malaise symptoms and bleeding tendency had started to decline and the patient received a COVID-19 PCR test. At day four the test resulted positive, and she reported no further complaints of intraoral bleeding. Six months later the taste of the patient was still distorted. For this patient with free medical anamnesis, we suggest that the patient had increased plasma levels of tissue plasminogen activator during the crucial postoperative period due to an acute COVID-19 infection. This led to increased plasmin levels with a hyper-fibrinolytic state as a consequence.

Current Concepts in the Management of Periodontitis

Periodontitis is a common disorder affecting >40% of adults in the United States. Globally, the severe form of the disease has a prevalence of 11%. In advanced cases, periodontitis leads to tooth loss and reduced quality of life. The aetiology of periodontitis is multifactorial. Subgingival dental biofilm elicits a host inflammatory and immune response, ultimately leading to irreversible destruction of the periodontium (i.e. alveolar bone and periodontal ligament) in a susceptible host. In order to successfully manage periodontitis, dental professionals must understand the pathogenesis, primary aetiology, risk factors, contributing factors and treatment protocols. Careful diagnosis, elimination of the causes and reduction of modifiable risk factors are paramount for successful prevention and treatment of periodontitis. Initial non-surgical periodontal therapy primarily consists of home care review and scaling and root planing. For residual sites with active periodontitis at periodontal re-evaluation, a contemporary regenerative or traditional resective surgical therapy can be utilised. Thereafter, periodontal maintenance therapy at a regular interval and long-term follow-ups are also crucial to the success of the treatment and long-term retention of teeth. The aim of this review is to provide current concepts of diagnosis, prevention and treatment of periodontitis. Both clinical and biological rationales will be discussed.

Clinical effectiveness of anorganic bovine-derived hydroxyapatite matrix/cell-binding peptide grafts for regeneration of periodontal defects: a systematic review and meta-analysis

Aim: To ascertain clinical effectiveness of anorganic bovine-derived hydroxyapatite matrix/cell-binding peptide (ABM/P-15) for regeneration of periodontal defects. Materials & methods: Electronic databases (National Library of Medicine [Medline by PubMed], Cochrane Library [Wiley], CINAHL [EBSCO] and Medline [EBSCO]) were systematically searched up to December 2019. Randomized controlled clinical trials comparing ABM/P-15 grafts to conventional surgery for intrabony and gingival recession defects were included and evaluated intrabony defects including clinical attachment level (CAL), probing depth and gingival recession. Results: A significant gain in CAL (1.37 mm), and reduction in probing depth (1.22 mm) were shown by ABM/P-15 grafts than open flap debridement (p < 0.00001). The subgroup analysis also showed better results for ABM/P-15 grafts in CAL gain for intrabony defects. For furcation and gingival recession defects, no significant difference was seen. Conclusion: The adjunct use of ABM/P-15 grafts in conventional periodontal surgery is useful for periodontal regeneration of intrabony defects.

CEMP-1 Levels in Periodontal Wound Fluid during the Early Phase of Healing: Prospective Clinical Trial

Objectives

Cementogenesis seems to be significantly compromised during tissue inflammation. In dental practice, surgical procedures are performed with the aim to regenerate periodontium including cementum. However, inflammation that occurs during the initial healing phases after surgery may impair regeneration of this tissues. The aim of the present study was to assess if surgical procedures designed to regenerate periodontium might affect levels of cementum protein-1 (CEMP-1) in periodontal wound fluid during early phase of healing.

Materials and Methods

In 36 patients, 18 intrabony periodontal defects were treated with regenerative therapy (REG group) and 18 suprabony periodontal defects were treated with open flap debridement (OFD group). In the experimental sites, gingival crevicular fluid was collected immediately before surgery, and periodontal wound fluid was collected 4, 7, 14, and 21 days after surgery. CEMP-1 levels were detected by indirect enzyme-linked immunosorbent assay technique.

Results

At the analysis, it resulted that there was a significant average difference in CEMP-1 values between the REG and OFD groups at baseline (p = 0.041), the CEMP-1-modeled average in the OFD group was lower by 0.45 ng/ml. There was a significant trend in CEMP-1 over time, and this trend was different among the 2 groups: the REG group showed a statistically significant rising CEMP-1 trend (0.18 ng/ml a week p = 0.012), while the OFD had a trend that was significantly lower (-0.22 ng/ml a week compared to the REG group trend p = 0.023), the OFD group lost on average 0.05 ng/ml a week. In REG sites, GCF protein levels resulted also related to clinical parameters.

Conclusions

During the initial inflammatory phase of periodontal healing, CEMP-1 levels decrease regardless of the surgical protocol applied. The surgical procedures used to regenerate periodontal tissue are able to reverse this trend and to induce significant increase of CEMP-1 in periodontal wound fluid after the first week postop.

Scaling and root planing vs. conservative surgery in the treatment of chronic periodontitis

A renewed interest in conservative surgical techniques has been fueled by new technology, changes in referral patterns to periodontists and a desire to achieve periodontal health in the least invasive, most cost-efficient manner possible. Trends suggest that an increasing amount of periodontal care is being provided in the offices of general dentists. If true, it is likely that patients receiving care in these offices will be offered simpler surgical treatment modalities that do not require an extensive armamentarium. The purpose of this article was to review the effectiveness of six relatively simple surgical techniques - gingivectomy, flap debridement, modified Widman flap, excisional new attachment procedure, modified excisional new attachment procedure and laser-assisted new attachment procedure - and to compare the results obtained using these procedures with the well-known clinical benefits of scaling and root planing. The intent was to determine whether the benefits of surgical procedures in the hands of most general dentists extend beyond those of conventional nonsurgical therapy.

Evaluation of anorganic bovine-derived hydroxyapatite matrix/cell binding peptide as a bone graft material in the treatment of human periodontal infrabony defects: A clinico-radiographic study

Background:

Various bone graft materials have been used in the treatment of periodontal defects. A synthetic bone substitute material composed of P-15 with anorganic bone mineral has been scantly studied. Hence, the present study was aimed to evaluate and compare the efficacy of anorganic bovine-derived hydroxyapatite matrix (ABM)/cell binding peptide (P-15) in human periodontal infrabony defects with that of open flap debridement (OFD) alone.

Materials and Methods:

A split-mouth, randomized controlled clinical study was designed to investigate the efficacy of ABM/P-15. In this clinical trial, 10 patients having bilateral periodontal infrabony defects were treated either with ABM/P-15 or OFD and followed for a period of 9 months. At baseline and at 9 months probing pocket depth (PPD), relative attachment level (RAL), depth of a defect, and radiographic bone level were measured; and compared between test and control sites.

Results:

A statistically significant reduction (P < 0.001) in PPD was observed in test sites compared to control sites. Both sites showed a gain in RAL without any significant difference. Similarly, the radiographic evaluation revealed significantly higher radiographic defect fill in test sites as compared to control sites (P < 0.001).

Conclusion:

ABM/P-15 bone graft material appears to be useful and beneficial in the treatment of human periodontal infrabony defects.

Treatment of intrabony defects with bovine-derived xenograft alone and in combination with platelet-rich plasma: a randomized clinical trial

BACKGROUND

In the treatment of periodontal intrabony defects, the benefits of adding platelet-rich plasma (PRP) to a bone replacement grafting material have not been tested. The purpose of this study was to compare the clinical outcomes obtained by the combination of PRP and a bovine derived xenograft (BDX) to those obtained from the use of the bone replacement graft alone.

METHODS

Thirteen patients were enrolled in a randomized, split mouth, double-masked clinical trial. Bilateral defects were matched according to their intrasurgical measurements. Qualifying defects had loss of attachment of > or = 6 mm, a radiographically detectable defect of > or = 4 mm, at least two remaining osseous walls, and not primarily related to a furcation involvement. After the hygienic phase, at the baseline examination, probing depth (PD), clinical attachment level (CAL), and recession (REC) were measured. During open flap debridement, the defects were randomly assigned to receive either BDX mixed with PRP or BDX alone. Baseline osseous intrasurgical measurements were obtained. Post-surgical follow-up and maintenance were performed and PD, CAL, and REC were remeasured at 6 months. The mean baseline and 6-month PD, CAL, and REC of the deepest buccal and lingual measurements related to the defect for each group were computed. The change from baseline to 6 months for each parameter measured was calculated. Pre- and postoperative comparisons were made between treatment groups at 6 months.

RESULTS

Randomization of the defects resulted in comparable groups (P > or = 0.05). At 6 months, paired t test comparisons within groups showed statistically significant benefits with both treatment modalities (P < or = 0.05). The mean changes (delta) at 6 months for the test and the control groups at the deepest sites were: PD reduction: 3.54 and 2.53 mm; CAL gain: 3.15 and 2.31 mm; and REC: -0.38 and -0.23 mm, respectively. Paired t test comparisons yielded significant differences between treatments for PD and CAL (P < or = 0.05).

CONCLUSION

In this 6-month clinical trial, the addition of a high concentration of autologous platelets to a bovine derived xenograft to treat intrabony defects significantly improved their clinical periodontal response.

Treatment of plaque-induced gingivitis, chronic periodontitis, and other clinical conditions

The inflammatory components of plaque induced gingivitis and chronic periodontitis can be managed effectively for the majority of patients with a plaque control program and non-surgical and/or surgical root debridement coupled with continued periodontal maintenance procedures. Some patients may need additional therapeutic procedures. All of the therapeutic modalities reviewed in this position paper may be utilized by the clinician at various times over the long-term management of the patient's periodontal condition.

The osteoinductive potential of demineralized freeze-dried bone allograft in human non-orthotopic sites: a pilot study

BACKGROUND

The use of demineralized freeze-dried bone allograft (DFDBA) in periodontal therapy is widely accepted. In addition to histologic studies demonstrating its role in regenerating the attachment apparatus, its recognized ability to exhibit osteoinduction in small laboratory mammals has prompted many clinicians to regard it as osteoinductive when utilized in periodontal therapy. Despite such a theoretical deduction, evaluating and establishing the osteoinductive potential of DFDBA in humans has been problematic. The purpose of this study was to investigate, through the use of a novel implantation/recovery model, the potential of DFDBA to induce new bone formation at sites not normally considered capable of de novo osteogenic activity.

METHODS

Seven patients scheduled to undergo periodontal therapy utilizing non-absorbable membranes agreed to have sterile polypropylene mesh capsules placed adjacent to the primary surgical site for the purpose of this investigation. One capsule was left empty while the second capsule contained DFDBA. At the appropriate time interval for removal of the therapeutic membrane, the capsules were removed and submitted for histologic analysis. Five of the subjects had procedures directed at regenerating bone within molar furcations (guided tissue regeneration) and had the membranes and associated capsules removed between 6 and 8 weeks. The 2 remaining patients had procedures directed toward ridge augmentation (guided bone regeneration) and had the membranes removed either at 8 or 9 months, respectively. In addition, one of the 2 long-term membrane patients had liberal cortical penetration performed directly beneath the implanted capsule.

RESULTS

Histologic analysis of all recovered capsules by 2 independent oral and maxillofacial pathologists could not confirm the presence of either osteoblastic or osteoclastic activity associated with the DFDBA particles, although the 2 longer-term specimens clearly exhibited trace amounts of vital bone non-contiguous with the implanted material.

CONCLUSIONS

The results of this pilot study do not support the osteoinductive potential of DFDBA when utilized in quantities normally associated with periodontal bone grafting, although they do support the use of this implantation/recovery model to study other preparations and mechanisms of bone formation.

Effects of pretreatment clinical parameters on bioactive glass implantation in intrabony periodontal defects

BACKGROUND

The various methods for regeneration of periodontal tissue that have been developed can be classified into guided tissue regeneration and bone implantation. Since the implantation materials have shown both deficiencies and merits, dentists have begun exploring the bioactive glass first used in plastic surgery. This paper examines the effectiveness of this new material on periodontal intrabony defects.

METHODS

Clinical effects of bioactive glass implantation in intrabony periodontal defects were evaluated 6 months after surgery in 38 intrabony defects from 38 patients with chronic periodontitis. Twenty-one experimental defects received bioactive glass implantation (test group), while 17 control defects were treated with a flap procedure only (control group). The criteria for comparative observation were preoperative and postoperative probing depth (PD), clinical attachment level (CAL), bone probing depth (BPD), and gingival recession.

RESULTS

Reductions in PD were observed in both groups (P<0.01). The reduction in PD was significantly greater in the test group when preoperative PD exceeded 7 mm (P<0.01). Improvements in CAL were also observed in both groups (P<0.01), with the test group showing significantly greater gains (P<0.05). In those cases where preoperative CAL was less than 7 mm, there was no statistically significant difference between the two groups. Reduction in BPD was observed in both groups, with the test group showing significantly greater reduction (P <0.01). There was no significant difference in BPD change, however, when preoperative BPD was < or =7 mm. Significantly greater reduction of BPD in the test group was observed when intrabony defect depth was >4 mm (P <0.05). Significant improvements in PD, CAL, and BPD were noted in the test group when the crestal involvement exceeded 100 degrees. Correlation test between various clinical parameters indicated that greater changes in PD and CAL in the test group were observed when preoperative CAL was large (P<0.001), and greater changes in PD (P<0.05), CAL (P<0.01), and BPD (P<0.05) were noted when preoperative BPD was large. Correlation between crestal involvement and CAL change was noted only in the control group (P<0.01). High correlations were observed between PD changes and CAL changes and between CAL changes and BPD changes in both groups.

CONCLUSIONS

Use of a bone substitute in a flap operation resulted in significantly greater improvements in CAL and BPD over flap operation alone and seemed to have positive effects in postoperative PD, CAL, and BPD in those cases with more severe preoperative CAL and BPD.

Spontaneous repositioning of pathologically migrated teeth

BACKGROUND

There is limited clinical evidence that pathologically migrated teeth may reposition themselves after conventional periodontal treatment. The current research was carried out to determine the frequency of spontaneous repositioning of pathologically migrated teeth after routine periodontal therapy, and to study the relation between the severity of migration and the degree of repositioning following treatment.

METHODS

Sixteen patients with moderate to severe periodontal disease and presenting 33 diastema sites secondary to pathologic migration participated in this study. After conventional periodontal treatment had been performed, reactive repositioning was assessed by measuring the space between pathologically migrated teeth and adjacent teeth on study models obtained at baseline, re-evaluation at 6 weeks after scaling and root planing, and 4 months after surgery.

RESULTS

After scaling and root planing only, 48.5% of all sites exhibited some degree of repositioning with 36.4% of all sites closing completely. After surgery (6 months after baseline observations), 69.7% of all sites exhibited some degree of repositioning with 51.5% of all sites closing completely. When only small to moderate diastemata were considered (<1 mm), 77.8% of sites closed completely.

CONCLUSIONS

The findings of this study support the hypothesis that spontaneous repositioning after conventional periodontal treatment is likely, particularly when only light to moderate degrees of pathologic migration are considered. We hypothesize that this spontaneous movement is due to wound contraction during healing.

Effects of expanded polytetrafluoroethylene and polylactic acid barriers on healthy sites

The configuration of the barrier devices to treat interproximal defects by guided tissue regeneration (GTR) necessitates inclusion of healthy adjacent teeth to secure the barriers in place. The purpose of this study was to evaluate the effects of expanded polytetrafluoroethylene (ePTFE) and polylactic acid (PLA) barrier devices on probing depth (PD), clinical attachment level (CAL), and crestal bone height in healthy sites. The study included 30 patients who were in an earlier study which compared the effects of GTR utilizing an ePTFE or a PLA barrier in intrabony defects. Thirty defects were randomly assigned to receive either a PLA (test) or an ePTFE barrier (control) after open flap debridement. The sites in this investigation included those healthy sites in the immediately adjacent non-affected teeth covered by the barriers. CAL and PD were measured at baseline and 12 months. Intrasurgical crestal bone height was recorded at the time of barrier placement and at a 12-month re-entry. Two-sample t-test comparisons of PD and CAL measurements between barrier device covered sites at baseline (PD: ePTFE, 2.32+/-0.51; PLA, 2.59+/-0.74; CAL: ePTFE, 2.71+/-0.66; PLA, 2.59+/-0.65 mm), and at one year (PD: ePTFE, 2.14+/-0.37; PLA, 2.07+/-0.56; CAL: ePTFE, 3.14+/-1.05; PLA, 2.75+/-0.73 mm) were not statistically different (P > 0.05). Paired t-test was utilized to compare changes in PD, CAL, and crestal bone height from baseline to 12 months. A statistically significant reduction in PD was found in the PLA group (delta = -0.52, P = 0.01) while no significant change was found in the ePTFE group (delta = -0.18, P = 0.18). Change in CAL was statistically significant in the ePTFE group (delta = 0.43, P = 0.02) while no significant change was found in the PLA group (delta = 0.16, P = 0.39). Crestal bone height changes from baseline to 12 months were statistically different for both groups (ePTFE, delta = 0.8 mm, P = 0.001; PLA, delta = 0.6 mm, P = 0.001). These resorptive changes, when compared between treatment groups were not statistically different (P > 0.05). In conclusion, the placement of ePTFE or PLA barriers on healthy sites resulted in probing depth reductions and loss of attachment of 0.5 mm or less. Additionally, both groups exhibited less than 1.0 mm of crestal bone resorption.

Guided tissue repair of complete buccal dehiscences associated with periapical defects: a clinical retrospective study

Apical surgery can enhance the success of restoring certain endodontically treated teeth. New regenerative surgical modalities, with emphasis on guided tissue regeneration, or GTR, have expanded clinicians' ability to retain teeth that previously were considered to be beyond restoration. The retrospective clinical study described in this article demonstrates that the use of GTR without the use of allograft demineralized bone achieves regeneration that is clinically and radiographically indistinguishable from the surrounding bone. The author presents the indications and contraindications for case selection, surgical management and postoperative findings for this treatment option.

Assessment of guided tissue regeneration procedures in intrabony defects with bioabsorbable and non-resorbable barriers

THE PURPOSE OF THIS STUDY was to assess periodontal regenerative techniques in intrabony defects utilizing a bioabsorbable, polylactic acid (PLA) barrier or the non-resorbable, expanded polytetrafluoroethylene (ePTFE) barrier. Thirty patients (26 to 64 years old) each with one radiographically evident intrabony periodontal lesion of probing depth > or = 6 mm participated in a 12-month controlled clinical trial. The subjects were randomly divided into two independent groups. The test group (n = 16) received a PLA barrier. The control group (n = 14) received an ePTFE barrier. Plaque index (PI), gingival index (GI), probing depth (PD), clinical attachment level (CAL), and bone fill were recorded by a single calibrated examiner not involved with the surgical treatment prior to surgery, and at 6, 9, and 12 months postsurgery. The treatment results were statistically analyzed utilizing two sets of data. The "averaged-site" data set consisted of values computed from the averaging of measurements from all sites encompassing the defect. The second data set was comprised of only the deepest measurement of the defect. Statistical tests used to analyze these data sets included the t-test and paired t-test for parametric data and the Wilcoxon rank sum test and the Wilcoxon signed rank test for non-parametric data. Analyses with both the averaged-site data and deepest-site data resulted in significant improvements in PD reductions, CAL, and bone fill, after 12 months of healing with both the PLA and ePTFE barrier devices. Comparisons of healing response between treatments found no significant differences when the averaged-site data were analyzed. When only the deepest site of the defect was considered, the control group resulted in significantly more attachment gain (ePTFE, 3.36 mm; PLA, 1.75 mm; P < 0.02) and shallower probing depths (ePTFE, 3.29 mm; PLA, 4.69 mm; P < 0.01) than the test group. In intrabony defects, the use of PLA or ePTFE barriers in GTR procedures yielded comparable clinical results; however, in this study, data analysis using the deepest site of the defect found, after 12 months of healing, significantly more attachment gain and shallower probing depths with ePTFE.

Healing of intrabony defects and its relationship to root canal therapy. A histologic and histometric study in dogs

The purpose of this study was to evaluate the importance of root canal therapy in the healing process of severe intrabony defects. Four beagle dogs were used and 32 interproximal intrabony defects, up to the apical third, were created. Wire ligatures were placed into these defects for plaque accumulation. Three weeks later, the ligatures were removed and 4 different treatment modalities were employed: group 1) scaling and root planing (SRP); group 2) modified Widman flap (MWF); group 3) modified Widman flap and root canal therapy performed at the same time (RCT/MWF); and group 4) modified Widman flap and root canal therapy performed 3 weeks after the surgical procedure (MWF + RCT). Postoperative oral hygiene was obtained by spraying a 0.12% chlorhexidine solution 3 times a week. The animals were sacrificed 7 weeks after treatment. Blocks were obtained and processed for routine histology. Results were expressed as a percentage of the total defect length (TDL). No differences were observed when SRP was compared to MWF. New bone formation (BF) presented better results for SRP (43.4%) and MWF (53.4%) when compared to RCT/MWF (15.5%). New cementum formation (CF) presented better results for SRP (59.8%) and MWF (64.6%) when compared to RCT/MWF (19.3%) and MWF + RCT (31.5%). Connective tissue repair (CTR) presented better results for SRP (72.4%) and MWF (74.2%) when compared to RCT/MWF (47.5%) and MWF + RCT (44.4%). Results were statistically significant at the level of 0.05. Within the limits of this study, it was concluded that root canal therapy performed simultaneously or 3 weeks after surgery modified the healing of intrabony defects, impairing new bone formation, new cementum formation and new attachment.

Human histologic evaluation of HTR polymer and freeze-dried bone allograft. A case report

This case report compares the results of placement of HTR (Hard Tissue Replacement Synthetic Bone) and freeze-dried bone allograft (FDBA) in the same patient. 2 notches were made in each of 6 teeth, 1 at the gingival margin and the other at the most apical level of calculus. Soft tissue responses with both materials included probing depth reduction, gingival shrinkage and gain in clinical attachment. Histological sections of block extraction sites 30 months after placement of either material showed no signs of new attachment. Little or no inflammation was present with both materials. There was also an absence of all FDBA particles which assumes complete resorption of this material prior to 30 months. Gingival shrinkage resulted in the exposure of the gingival and calculus notch in all FDBA treated sites. Gingival epithelium was found adjacent to the gingival notch in all HTR treated sites. The calculus notch in HTR treated sites was lined by junctional epithelium with connective tissue and bone opposing the adhesion. HTR particles were present and surrounded by connective tissue or bone. HTR appears to serve as a scaffold for new bone formation when in close contact with alveolar bone.

Implications of cellular and molecular biology advances in periodontal regeneration

BACKGROUND

The mechanisms by which new periodontium is established on root surfaces previously exposed to periodontal disease has been an area of active research interest for the past decade.

METHODS

Recently, histological examination of periodontal regeneration has revealed a complex process orchestrated by temporo-spatial specific cell-matrix interactions.

RESULTS

Advances in cell and molecular biology techniques have provided invaluable tools to begin investigating the cascade of events occurring periodontal regeneration.

CONCLUSION

This report summarizes current understanding of the cellular and molecular aspects of periodontal regeneration and determines the clinical relevance of these findings.

Treatment of mandibular 3-wall intrabony defects by flap debridement and expanded polytetrafluoroethylene barrier membranes. Long-term evaluation of 32 treated patients

The purpose of this study was to evaluate the healing potential of deep, primarily 3-wall intrabony defects which were treated by flap debridement and expanded polytetrafluoroethylene (ePTFE) membranes and followed for extended time periods. All of the treated defects were in the mandibular arch. Thirty-two patients were treated and re-examined at an average of 3 years 5 months. Twenty-four of these patients had re-entry procedures at the second examination. Sixteen of these patients were examined a third time at an average of 4 years 3 months. The patients were evaluated for changes in probing depth (PD), clinical attachment level (CAL), recession, changes in crestal resorption, and defect bone fill. The paired t-test for related samples was used to test for differences between examinations. Between Exams 1 and 2 there was a statistically significant reduction of pocket depth (3.8 mm), gain in clinical attachment level (4.2 mm), and an increase in recession (-1.2 mm). For the 24 patients who had re-entry procedures there was an average defect fill of 4.3 mm (P < 0.0001) and 0.33 mm of crestal resorption (P < 0.0001). The 16 patients who were examined 3 times sustained decreases in PD, gains in CAL, and recession recorded at the second examination. These changes were statistically significant at Exam 3. The results of this study demonstrate that deep, 3-wall intrabony defects treated by debridement and ePTFE barrier membranes will have significant decreases in PD, gains in CAL, recession, decreases in crestal resorption, and gains in bone fill.(ABSTRACT TRUNCATED AT 250 WORDS)

Epithelial-connective tissue interaction on the tooth surface: an in vitro model

In the present study, and in vitro system was developed and designed to examine the interaction between gingival fibroblasts (GF) and epithelial cells (EC) on the tooth surface. Porcine roots were cut transversely into 300 microns-thick root slices (RS). Gingival explants were placed on the upper RS surface and cultured in a defined medium permissive for the growth of EC. After 4 or 6 days, RS yielding EC were transferred onto confluent cultures of GF and further co-cultured for either 4 or 8 d. Cultures were then fixed and examined by SEM. The upper RS surfaces and the upper half of their peripheral aspect were covered by EC. The lower half of the peripheral RS surfaces were populated by GF originating from the confluent culture of GF. EC and GF made contact at approximately the middle of the side of the root slice. In cultures of epithelial components grown in defined medium for either 4 or 6 d and harvested 4 d after assembling the system, the EC-GF junction was located 117 +/- 45 and 271 +/- 82 microns, respectively from the upper RS aspect. Extending the co-culture period did not affect the EC-GF junction location. These results indicate that GF-EC contact stops the migration of these cells on root surfaces in vitro. The described system should be valuable for studying cellular events that may affect the formation of a new dentogingival junction following surgical periodontal therapy.

Collagen membranes prevent apical migration of epithelium and support new connective tissue attachment during periodontal wound healing in dogs

The capacity of collagen membranes to prevent the apical migration of epithelium and to support new connective tissue attachment was assessed in experimental periodontal defects in dogs. Experimental periodontal defects were produced in 8 mongrel dogs by removing the alveolar bone and the periodontal ligament over the most coronal 5 mm of the labial aspect of the maxillary canines. Experimental defects associated with the right canine and its surrounding bone were covered by collagen membranes prepared by air drying gels of rat type I fibrillar collagen. Flaps were repositioned and sutured. The contralateral control defects were sham-operated without using collagen membranes. Animals were killed, 10 and 30 days after surgery, 4 at each time point. The experimental and control sites were processed for histologic and histomorphometric evaluation. At 10 d, the average distance between the apical margin of the epithelium and the apical level of the defect (EA) sites was 3.20 +/- 0.55 mm for the experimental sites and 0.73 +/- 0.18 mm for the controls. The experimental root surfaces apical to the epithelium and the collagen membranes were covered by connective tissue cells. At 30 d, the EA for experimental and control sites were 2.55 +/- 0.36 mm and 0.47 +/- 0.30 mm, respectively. In the experimental sites healing by long junctional epithelium was observed in the coronal 40% of apico-occlusal dimension of the defect and new connective tissue attachment with inserting fibers in the apical 55% of the defect length. No new bone formation was observed. In the control sites, pocket formation was found in the most coronal one-third of the defect.(ABSTRACT TRUNCATED AT 250 WORDS)

Apical migration of oral epithelium in experimental dehiscence wounds

The purpose of the present investigation was to determine if the placement of free mucosal grafts would delay the apical migration of oral epithelium into surgically created dehiscence wounds. Dehiscence wounds, measuring 8 x 6 mm, were surgically created on the mandibular canines of 5 beagle dogs. The exposed root surface was then curetted and horizontal grooves were made, one at a point just below the gingival sulcus and the other at the apical border of the dehiscence. Experimental teeth received free alveolar mucosal grafts while the contralateral teeth served as controls. The grafts were placed with the epithelial side against the tooth surface to bridge the dehiscence at the level of the coronal notch and were sutured in place. The flaps were then repositioned (over the mucosal grafts) and sutured. Apical migration of the oral epithelium, after 10 days, was assessed histologically using the coronal and apical grooves as points of reference. The oral epithelium was detected in the coronal one half of the dehiscence, in both the control and experimental teeth. There were no significant differences observed between the two, suggesting that the placement of a mucosal graft, as described here, provides little benefit in delaying apical migration of oral epithelium. The fact that the epithelium failed to reach the apical half of the dehiscence may indicate that features of this wound model may help our understanding of epithelial cellular kinetics operative in periodontal wound healing.

Restorative margins and periodontal health: a new look at an old perspective

The indiscriminate placement of the margins of dental restorations into the gingival crevice for the purpose of esthetics or protection from decay can no longer be considered good practice. The junctional epithelium and the supracrestal fibers, together, have been called the biologic width, which is considered to have a length of 2 mm. A more accurate term for the biologic width, one that expresses the function and diversity of the component tissues while avoiding reference to dimension, is the "subcrevicular attachment complex." The most accurate anatomic structure from which to take measurements for margin placement is the healthy, stable gingival margin. It is clinically visible, unlike the biologic width, and should replace the latter as the landmark of choice for placing dental margins. Surgical crown lengthening will be necessary when restorations will end at or below the alveolar crest.

The value of systemically administered metronidazole in the modified Widman flap procedure

This double-blind cross-over study was undertaken to assess the effect of systemically administered metronidazole when used as an adjunct to periodontal surgery for the treatment of moderate and advanced periodontitis. The effect of metronidazole was compared with that of placebo in patients undergoing modified Widman flap procedures in two areas of the same jaw which could be matched for type of tooth and severity of the periodontal disease. Clinical and microbiological parameters were examined prior to surgery and then 7 days, 1 month, and 3 to 6 months, postoperatively. The clinical parameters recorded were pocket depth (PD), Sulcus Bleeding Index (SBI), probing attachment level (PAL), and patients' preference and pain score. Subgingival plaque samples were studied with dark-field microscopy for differential bacterial count. Pocket depths and SBIs were reduced significantly at all stages, in both groups. Probing attachment levels increased at 7 days, to significant levels only in the metronidazole group, subsequently PALs decreased in both groups with no significant differences between the groups. Although the differential bacterial count altered markedly in both groups at all times, only the straight rod count at 1 month was significantly (P less than 0.05) lower in the metronidazole group. Metronidazole with surgery did not exert a significantly greater beneficial effect than placebo with surgery.

Mucoperiosteal flaps with and without removal of the pocket epithelium

The purpose of this study was to clinically evaluate the need for elimination of the pocket epithelium during mucoperiosteal flap surgery aimed at reattachment or readaptation. A split mouth design was used in 13 patients with two bicuspids and two molars included in each quadrant. Two surgical techniques were compared. One of the quadrants received a modified Widman flap with removal of the pocket epithelium, while the contralateral side received a crevicular flap without removing the pocket epithelium. One month after the hygienic phase was completed, the following measurements were taken: Gingival Index, Plaque Index, gingival crevicular fluid flow, mobility, furcation involvement, level of attachment, pocket depth and gingival recession. In addition to these measurements, which were taken immediately prior to the surgery (baseline), 1- and 3-month postsurgical measurements were also taken. Gingival recession was recorded immediately after the flaps were replaced and sutured. All data were analyzed statistically using paired t test and sign test. The biometric results showed that without the removal of the pocket epithelium, good clinical results relative to gain in clinical attachment levels and reduction in probing depth were achieved. Greater gingival recession occurred on the crevicular flap side postsurgically when compared to the modified Widman flap. The other clinical parameters remained the same at the three time intervals. This was true within each technique and when both techniques were compared.

Immunohistochemical study of structural proteins in developing junctional epithelium

The objective of this study was to investigate structural proteins of ameloblasts, reduced enamel epithelium and junctional epithelium using antikeratin antibodies to determine if keratin expression changes as ameloblasts differentiate to cells of junctional epithelium. Block sections of fully erupted, partially erupted and unerupted molar and incisor teeth were removed at necropsy from monkeys age 2, 5, 6 and 7 years. Tissues were fixed in Carnoy's fixative, decalcified in Kristensen's solution for 4 to 8 weeks, embedded in paraffin and sectioned at 5 mu. Representative sections were stained with hematoxylin and eosin. Remaining sections were stained with antikeratin antibodies AE1, AE3, 34 beta E12, 35 beta H11 and anti-40kD using the avidin-biotin-conjugated immunoperoxidase method. Results were analyzed qualitatively for presence or absence of staining products. Antibody 35 beta H11 reacted with ameloblasts and reduced enamel epithelium during the early maturation phase of tooth development but not with the reduced enamel epithelium of erupting teeth or with junctional epithelium. The anti-40kD antibody stained ameloblasts and reduced enamel epithelium of unerupted teeth and teeth erupting through oral epithelium; however, junctional epithelium of partially erupted and fully erupted teeth were unstained. Antibodies AE1, AE3 and 34 beta E12 stained ameloblasts and all layers of reduced enamel epithelium and junctional epithelium in all stages of development. These results suggest a relationship between expression of structural proteins and changes during development and differentiation of ameloblasts to junctional epithelial cells.

Human gingival attachment responses to subgingival crown placement. Marginal remodelling

13 teeth in block were extracted from 2 patients. Their facial periodontal condition was essentially within normal clinical limits. Temporary crowns covering the bevel were placed below the base of the crevice 1 to 8 weeks prior to extraction. At time of extraction, all blocks were decalcified, the temporary crown dissolved, and the blocks prepared for histologic examinations using buccolingual cut, step serial sections. Histologic data revealed reformation of a new supracrestal attachment unit within 1 week following crown placement. The reformation of the gingival unit consisted of marginal recession with apical and lateral migration of the junctional epithelium to the level of remaining cementum inserted fibers. With gingival recession and migration of junctional epithelium, resorption of crestal portions of the facial plate occurred. However, periodontal fibers anchored into cementum opposite the resorbed bone were not lysed. Rather, the attached fibrillar ends appeared to interdigitate with fibers from the corium of the facial gingiva at this site, thereby forming a more apically located crestal attachment. This response may be one mechanism of reformation of the gingival attachment unit taking place following mechanical and/or surgical injury to this site and is completed often, within 2 weeks after injury.

Regeneration of alveolar bone following surgical and non-surgical periodontal treatment

The purpose of this investigation was to examine the regeneration of alveolar bone following surgical and non-surgical periodontal treatment. A total of 16 patients who had advanced periodontitis and demonstrated angular bony defects on radiographs participated in the study. After the initial examination, they received instruction in oral hygiene and had their teeth thoroughly scaled. When the individual patient at 2 succeeding appointments had plaque on less than 20% of the tooth surfaces, one maxillary and one mandibular quadrant was treated with the modified Widman flap procedure while one of the remaining quadrants was treated with the reverse bevel flap procedure. The last quadrant was treated with root planing under local anesthesia. None of these procedures included bone contouring. Following treatment, the patients were recalled every 2 weeks for professional tooth cleaning. Radiographs taken 12 months following treatment revealed that only minor changes in the bone level had occurred in areas with horizontal bone loss following the various treatment modalities. Following the modified Widman flap procedure, however, a statistically significant coronal regrowth of bone (0.5 mm) had occurred in angular bony defects. The majority of the angular bony defects persisted following all 3 treatment modalities.

A follow-up study of apicoectomized teeth with total loss of the buccal bone plate

Opinions differ as to whether or not teeth with advanced marginal bone loss should be subjected to periapical surgery. The purpose of this retrospective investigation was to study the results after apicoectomy on teeth that showed total buccal bone loss at the time of the operation. The material consisted of twenty-seven teeth in 27 patients, fifteen males and twelve females, 23 to 63 years old at the time of the operation. The observation time varied from 0.5 to 7 years (mean, 3 years). Ten operations (37%) were regarded as successful, nine (33%) as uncertain, and eight (30%) as unsuccessful. The success rate was not so low that an apicomarginal communication should be regarded as a contraindication for apicoectomy. Apicoectomy should be performed, especially if the alternative is an otherwise unnecessary prosthetic reconstruction.

Effect of retention of gingival sulcular epithelium on attachment and pocket depth after periodontal surgery

Both the modified Widman flap and the intrasulcular incision technique produced significant and similar reductions in pocket depth and increases in attachment. Loss of attachment occurred where the initial pocket depth was less than 3 mm. Both techniques resulted in significant and similar increases in gingival recession. Neither technique affected tooth mobility or plaque scores to a clinically important degree. Historically, the necessity for removal of the sulcular epithelium in the course of periodontal therapy is a widely accepted tenet. This study fails to clinically validate this concept.

Periodontal repair after surgical debridement with and without cartilage allografts

The effect of a cartilage allograft on healing in intrabony defects treated by open flap curettage was investigated at 130 surgical sites in 4 patients. Thinned mucoperiosteal flaps were elevated and the intrabony defects were debrided. A stent with stainless steel pins was used to measure defect depth at fixed locations adjacent to the root surfaces. The bony defects treated ranged from 0-9 mm with a mean intraosseous depth of 2.4 mm. 62 sites received cartilage implants and 68 sites were treated by surgical debridement only. The flaps were readapted and sutured to the level of the alveolar crest. After 16 weeks the defects were remeasured. Both treatment methods resulted in a mean apical shift of -0.09 mm of the base of the defects that were less than 3 mm and a mean coronal shift of 0.9 mm in defects that were greater than 3.5 mm in depth. The repair in deeper lesions increased with the number of intrabony walls. Mean pocket depth at flap curettage sites was reduced from 5.4-3.3 mm (P less than 0.01) at 16 weeks. At sites receiving the cartilage, the mean pocket depth decreased from 5.6-3.6 mm (P less than 0.01). Pocket reduction resulted from a combination of surgical recession and a mean gain of 1 mm in clinical attachment (P less than 0.05 for flap curettage sites only). The cartilage implants provided no statistically significant advantage in either bony or soft tissue repair over flap debridement alone. Although bony repair is influenced by depth and configuration of the intrabony defects, significant gains in attachment and reductions in pocket depth may occur independently of changes at the base of the intrabony defects.

Connective tissue reattachment as related to presence or absence of alveolar bone

The present study was designed to examine if alveolar bone, located adjacent to a root surface deprived of its periodontal ligament and cementum layer, can stimulate the reformation of a connective tissue attachment. The maxillary and mandibular incisors in 3 monkeys were extracted. Immediately after tooth extraction, the buccal root surfaces of the incisors from the left side of the jaws were planed by means of curettes to a level corresponding to half the root length. All teeth were then reimplanted into their original sockets. However, before tooth reimplantation, the buccal alveolar bone plate was removed in 2 of the monkeys to a level corresponding to half the depth of the sockets. The animals were sacrificed 6 months after the reimplantation procedure. The jaws were removed and histological sections of the experimental teeth and adjacent periodontal tissues were produced. The sections were analyzed in the microscope and subjected to histometric measurements. The results demonstrated that, irrespective of the presence or absence of alveolar bone, a fibrous reattachment failed to form on that part of the reimplanted teeth which had been deprived of their periodontal ligament. This indicates that alveolar bone located adjacent to a root surface may have limited influence on the biological conditions which determine whether periodontal healing results in connective tissue reattachment or new attachment.

Root surface smoothness or roughness in periodontal treatment. A clinical study

Twelve patients with localized advanced periodontitis were selected for this study. The 18 teeth used were divided into experimental and control groups. In both groups the loss of attachment and pocket depth were measured and modified Widman flap surgery was performed. In the experimental group, after root planing, a number of shallow horizontal grooves were made on the root surface to roughen them. Four months after surgery the same measurements were made. The results indicated that in both groups the pocket reduction and the gain of attachment were statistically significant. The differences between the two groups, as far as pocket reduction and gain of attachment are concerned, were not significant.

Healing responses of human intraosseous lesions following the use of debridement, grafting and citric acid root treatment. II. Clinical and histologic observations: one year postsurgery

This report details histologic healing responses at intrabony sites within two patients about 1 year after surgery. Treatment consisted of open flat debridement of the lesions. At specific sites, augmenting procedures such as autogenous grafts, allografts, synthetic grafts and citric acid root treatment were utilized. In addition, notches were made through calculus prior to root planing at specific root surfaces. These notches were placed at varying distances from the base of the lesion. Patients were followed postsurgically with frequent maintenance visits. Block sections were removed at the end of the experimental period. Clinical reduction in pocket depth was noted at all treated sites. This reduction consisted of limited pocket closure, marginal gingival recession and repocketing. Histologically, all specimens showed evidence of repair. The most mature repair appeared at sites treated with debridement and autogenous grafts. "Regeneration" of lost periodontal attachment was demonstrated by evidence of cementogenesis, osteogenesis and the presence of functionally oriented ligaments. However, the coronal regeneration appeared spatially limited. Allografts showed a similar, but less mature healing response. Synthetic graft material acted essentially as a "filler" within the defect. Citric acid root treatment did not demonstrate clear evidence of augmentation of the repair process. Of particular note in these human specimens was further histologic demonstration that "regeneration" potential apparently can only take place in close proximity to histologically viable periodontal ligament cells which may act as "donor sites" for coronal "regeneration" of lost periodontal attachment. This histologic response was observed regardless of treatment modalities used.