Maintenance of new attachment gained through guided tissue regeneration

Challenges and success in periodontal plastic surgery

To truly understand a field of study, one must delve into its past and examine the challenges and successes that have shaped its current practices. In the case of periodontal plastic surgery, recognizing how challenges induced changes over the last 70 years-from the 1950s to today-is essential to fully comprehend its evolution. This editorial provides a perspective on the field, highlighting the interrelationships between influential surgical techniques and advancements in research methodology. With each event building upon the last, the evolution of periodontal plastic surgery is a story of scientific progress and ongoing research, fostering a sense of community and shared knowledge.

Second Attempt of Guided Tissue Regeneration on a Previous Successfully Grafted Site with Periodontal Breakdown-A 5-Year Follow-up

Guided tissue regeneration (GTR) has been proven to promote attachment and regeneration of periodontal tissue. However, there is a 20 to 40% incidence of attachment loss on regenerated attachments reported in the literature. To my knowledge, this is the first case report on a second attempt in GTR on a previous successful grafted site with clinical attachment loss. A healthy 17-year-old Chinese male patient had GTR performed with xenograft particles and bovine resorbable membrane on his root-canal treated, fused upper right lateral incisor and upper right canine (#12-#13) in 2007. Probing depth on the mid-palatal region of #12-#13 was reduced to 4 mm and maintained for the next 4 years. But in the fifth year, probing depth increased to 11 mm with no endodontic symptoms, and a second attempt of GTR using the same materials was carried out. The probing depth at the surgical site was reduced to 4 mm and successfully maintained for another 5 years. Irregular maintenance and the presence of plaque retentive factor could have caused the clinical attachment loss on #12-#13. This case shows it is possible to attempt GTR on a previous successfully grafted site. GTR did not increase tissue resistance against periodontal breakdown. Hence, proper maintenance planning for GTR sites is important to prevent periodontal breakdown.

Texturized P(VDF-TrFE)/BT membrane enhances bone neoformation in calvaria defects regardless of the association with photobiomodulation therapy in ovariectomized rats

OBJECTIVES

The purpose of this investigation was to evaluate in vivo the response of bone tissue to photobiomodulation when associated with texturized P(VDF-TrFE)/BT in calvaria defects of ovariectomized rats.

MATERIALS AND METHODS

Wistar Hannover rats were submitted to ovariectomy/control surgery. Calvaria bone defects of 5-mm diameter were performed after 90 days of ovariectomy. The animals were divided into OVX (without laser (L) and membrane), OVX + P(VDF-TrFE)/BT, OVX + P(VDF-TrFE)/BT + L, and OVX + PTFE + L. It was utilized a low-intensity gallium-aluminum-arsenide laser (GaAlAs) with 780-nm wavelength and 30-J/cm² energy density in 12 sessions (120 s). Thirty days after the bone defect the animals were euthanized for histological, microtomographic, and molecular evaluation. Quantitative analysis was analyzed by statistical software for p < 0.05.

RESULTS

Histological parameters showed bone tissue formation at the borders of all group defects. The association of photobiomodulation and texturized P(VDF-TrFE)/BT was not synergistic and did not show significant changes in morphometric analysis and biomarkers gene expression. Nevertheless, texturized P(VDF-TrFE)/BT membrane enhanced bone repair regardless of the association with photobiomodulation therapy, with an increase of connectivity density when compared to the OVX + PTFE + L group. The association of photobiomodulation therapy and PTFE was synergistic, increasing the expression of Runx2, Alp, Bsp, Bglap, Sp7, and Rankl, even though not enough to reflect significance in the morphometric parameters.

CONCLUSIONS

The utilization of texturized P (VDF-TrFE)/BT, regardless of the association with photobiomodulation therapy, enhanced bone repair in an experimental model of osteoporosis.

In Vitro and In Vivo Study of a Novel Porcine Collagen Membrane for Guided Bone Regeneration

For years, in order to improve bone regeneration and prevent the need of a second stage surgery to remove non-resorbable membranes, biological absorbable membranes have gradually been developed and applied in guided tissue regeneration (GTR). The present study's main objective was to achieve space maintenance and bone regeneration using a new freeze-dried developed porcine collagen membrane, and compare it with an already commercial collagen membrane, when both were used with a bovine xenograft in prepared alveolar ridge bone defects. Prior to surgery, the membrane's vitality analysis showed statistically significant higher cell proliferation in the test membrane over the commercial one. In six beagle dogs, commercial bone xenograft was packed in lateral ridge bone defects prepared in the left and right side and then covered with test porcine collagen membrane or commercial collagen membrane. Alveolar height changes were measured. Histomorphometric results, in vitro and in vivo properties indicated that the new porcine collagen membrane is biocompatible, enhances bone xenograft osteoconduction, and reduces the alveolar ridge height reabsorption rate.

Long-term outcome following regenerative periodontal treatment of intrabony defects

This study aimed to evaluate the long-term outcome of the regenerative periodontal therapy of an intrabony defect in terms of tooth survival and clinical attachment level (CAL) stability. The association between failure and patient as well as tooth variables was assessed. Treatment records of the patients who received regenerative surgery and re-evaluation at 1-year post-surgery were screened. Patient and tooth variables, defect characteristics, and types of treatments were collected. Periodontal parameters were retrieved before regenerative surgery (baseline), 1-year post-surgery, and every visits of supportive periodontal treatment (SPT) until failure, including tooth loss or CAL loss ≥2 mm was found. In this study, treatment records from 89 patients were included. These patients continued SPT from 0.5-11.16 years. Of these patients, 92.1 % survived from tooth loss, while 61.8 % survived from CAL loss ≥2 mm compared to 1-year post-surgery. At the sites with residual pocket depth <5 mm, patients attending SPT >80 % had a significantly less percentage of teeth with CAL loss ≥2 mm compared to 1-year post-surgery than those attending SPT <80 %. However, at the sites with residual pocket depth ≥5 mm, no significant difference in the percentage of teeth with CAL loss ≥2 mm was found between patients attending SPT >80 % or <80 %. Smoking, patient's compliance, and residual pocket depth after regenerative surgery were significantly associated with tooth loss. However, these factors were not significantly associated with CAL loss compared to baseline or 1-year post-surgery.

The effect of brain-derived neurotrophic factor on periodontal furcation defects

This study aimed to observe the regenerative effect of brain-derived neurotrophic factor (BDNF) in a non-human primate furcation defect model. Class II furcation defects were created in the first and second molars of 8 non-human primates to simulate a clinical situation. The defect was filled with either, Group A: BDNF (500 µg/ml) in high-molecular weight-hyaluronic acid (HMW-HA), Group B: BDNF (50 µg/ml) in HMW-HA, Group C: HMW-HA acid only, Group D: empty defect, or Group E: BDNF (500 µg/ml) in saline. The healing status for all groups was observed at different time-points with micro computed tomography. The animals were euthanized after 11 weeks, and the tooth-bone specimens were subjected to histologic processing. The results showed that all groups seemed to successfully regenerate the alveolar buccal bone, however, only Group A regenerated the entire periodontal tissue, i.e., alveolar bone, cementum and periodontal ligament. It is suggested that the use of BDNF in combination with a scaffold such as the hyaluronic acid in periodontal furcation defects may be an effective treatment option.

Biocompatibility and cytotoxic evaluation of drug-loaded biodegradable guided tissue regeneration membranes

BACKGROUND

In periodontology, Guided Tissue Regeneration (GTR) is based on the concept of providing a space for entry of cells with regenerative potential into the wound environment to initiate the regeneration of structures lost due to periodontal disease. First generation GTR membranes were primarily non-absorbable membranes like expanded polytetrafluorethylene which required a second surgery for its removal. This led researchers to explore absorbable materials like collagen and synthetic biodegradable polymers to fabricate GTR membranes. In the present study, biodegradable Polylactic acid (PLA) is used to fabricate membranes with the potential to be used for GTR therapy.

MATERIALS AND METHODS

Biocompatibility of the PLA membranes were evaluated in a subcutaneous guinea pig model. Antimicrobial effect of the drug-loaded PLA membranes were assessed against a drug-resistant Staphylococcus aureus bacterial isolate. The cytocompatibility of the drug-loaded membranes were evaluated using HeLa cell lines.

RESULTS

The PLA membranes were shown to be biocompatible. The drug-loaded PLA membranes showed significant activity against the bacterial isolate. Among the drug-loaded membranes, tetracycline-loaded membrane showed minimal cellular toxicity.

CONCLUSION

The results of this study indicate that biodegradable drug-releasing polylactide membranes have the potential to be used for periodontal regeneration. It has the necessary characteristics of a GTR membrane like biocompatibility, space maintaining ability, and tissue integration. Among the various antimicrobial agents loaded in the PLA membranes, tetracycline-loaded membranes exhibited minimal cellular toxicity against HeLa cells; at the same time showing significant activity against a pathogenic bacterium.

Long-term clinical evaluation and SEM analysis of the e-PTFE and titanium membranes in guided tissue regeneration

AIM

This study aimed to evaluate clinical outcomes of titanium membrane and compare these findings with clinical outcomes of e-PTFE membrane, and to investigate the effect of bacterial contamination on both membranes with SEM during long-term healing.

RESULTS

Sixteen titanium and sixteen e-PTFE membranes were surgically placed adjacent to periodontally involved teeth. Seven titanium and 8 e-PTFE membranes were exposed between 4 and 6 weeks. There were no significant difference between groups for plaque and gingival index. Probing depth and clinical attachment level (CAL) were decreased in both groups when compared with baseline; however, these differences were not statistically significant. The CAL gains between the groups were statistically different in 3rd, 6th, 9th, 12th, and 24th months (p < 0.05), and the CAL gain was significantly higher in titanium membrane (p < 0.05). There was significant decrease in bleeding on probing from baseline in both groups (p < 0.05). Surfaces of 15 membranes were studied using SEM. The largest amount of bacteria was found on the external cervical surfaces of 15 exposed specimens. The entire surface showed the presence of slough epithelial cells, leukocytes, red blood cells, yeast, and microbial plaque. Thirteen external mid surfaces of the 15 specimens, external apical surfaces of three e-PTFE and 1 titanium membrane, internal collar surfaces of all specimens, internal mid surfaces of 5 e-PTFE and three titanium membranes and internal apical surface of only one e-PTFE membrane were infected.

CONCLUSIONS

This study demonstrated that titanium membrane is equivalent to e-PTFE membranes for GTR in the treatment of periodontal defects.

Periodontal and endodontic regeneration

Guided tissue regeneration (GTR) is effective in halting tissue and bone destruction and promoting new tissue and bone formation. Although the goal of complete and predictable regeneration still remains elusive, many techniques and materials have been developed that show good clinical and histologic outcomes. The most commonly used materials in GTR include bone replacement grafts from numerous sources, nonresorbable and bioabsorbable membranes, and recently growth hormones/cytokines and other host modulating factors. This article reviews the biologic rationale behind current techniques used for tissue/bone regeneration, reviews the most common materials and techniques, and attempts to explain the factors that influence the outcomes of these therapies.

Surgical guided tissue regeneration treatment of advanced periodontal defects: a 5-year follow-up study

OBJECTIVES

To study the 5-year outcome of combined use of guided tissue regeneration (GTR) barriers and bovine bone in advanced periodontal defects.

MATERIAL AND METHODS

In each of 24 patients, one defect was surgically exposed, debrided, filled with bovine bone, and covered with a bioresorbable barrier. Re-examinations were made after 1, 3, and 5 years.

RESULTS

Average full-mouth plaque scores (FMPS) were 14.5% at baseline and 10.7%, 9.8%, and 18.9% after 1, 3, and 5 years, respectively. Mean probing pocket depth (PPD) was 10.0 mm at baseline. Mean PPD reduction was 5.2 mm after 1 year, 5.6 mm after 3 years, and 5.3 mm after 5 years. Mean gingival recession was 1.0 mm after 1 year, 1.6 mm after 3 years, and 1.3 mm after 5 years. Mean gain in clinical attachment level (CAL) was 4.2 mm at the 1-year, 4.1 mm at the 3-year, and 4.3 mm at the 5-year examination. Smoking significantly influenced CAL change at all re-examinations. FMPS were significantly correlated with radiographic defect depth at the 5-year examination and CAL with smoking and FMPS at the 3-year examination.

CONCLUSION

Advanced periodontal defects can be successfully treated with the combined use of GTR barriers and bovine bone to substantially reduce PPD and achieve a stable, long-term gain of CAL.

Influence of autologous platelet concentrate on healing in intra-bony defects following guided tissue regeneration therapy: a randomized prospective clinical split-mouth study

OBJECTIVES

To investigate the influence of autologous platelet concentrate (APC) on early wound healing and regeneration outcomes following guided tissue regeneration (GTR) therapy.

MATERIAL AND METHODS

In 25 patients, two contralateral deep intra-bony defects were treated with beta-TCP and a bioresorbable GTR membrane. They were randomly assigned to test and control procedure. In test defects, APC was additionally applied. After 3, 6, and 12 months, healing results were assessed by clinical parameters and quantitative digital subtraction radiography.

RESULTS

Post-operative membrane exposures occurred in 48% of the test sites and 80% of the control sites. Both groups revealed a significant clinical attachment level (CAL) gain of 5 mm after 12 months. Eighty-eight per cent of test and control sites showed a CAL gain of > or =4 mm. No clinical parameter revealed significant differences between test and control sites. A significant bone density gain was found in both groups after 3, 6, and 12 months. Only after 6 months, the bone density gain was significantly greater in the test defects.

CONCLUSION

Within the limits of this study, autologous platelet concentrate did not seem to have a noticeable influence on the clinical and most of the radiographic outcomes following GTR. However, APC might reduce the occurrence of post-operative membrane exposures and accelerate bone density gain.

Treatment of Intrabony Defects With an Enamel Matrix Protein Derivative or Bioabsorbable Membrane: An 8-Year Follow-Up Split-Mouth Study

BACKGROUND

Treatments with either an enamel matrix protein derivative (EMD) or guided tissue regeneration (GTR) have been shown to promote periodontal regeneration. However, until recently, only limited data have been available on the long-term clinical results following these regenerative techniques. Therefore, the aim of this study was to present the 8-year results of a prospective, controlled, split-mouth clinical study evaluating the treatment of intrabony defects with EMD or GTR.

METHODS

Ten patients, each of whom displayed one pair of intrabony defects located contralaterally in the same jaw, were randomly treated with EMD or with GTR by means of bioabsorbable membranes. The following clinical parameters were evaluated at baseline and at 1 and 8 years after treatment: plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), gingival recession (GR), and clinical attachment level (CAL). The primary outcome variable was CAL. No statistically significant differences between the groups were found at baseline.

RESULTS

The sites treated with EMD demonstrated a mean CAL change from 9.5 +/- 1.2 mm to 6.3 +/- 1.3 mm (P <0.001) and 6.7 +/- 1.6 mm (P <0.001) at 1 and 8 years, respectively. No statistically significant differences were found between the 1- and 8-year results. Sites treated with GTR showed a mean CAL change from 9.7 +/- 1.3 mm to 6.7 +/- 0.9 mm (P <0.001) at 1 year and 6.8 +/- 1.2 mm (P <0.001) at 8 years. The CAL change between 1 and 8 years did not present statistically significant differences. Between the treatment groups, no statistically significant differences in any of the investigated parameters were observed at 1 and at 8 years. However, the study does not have the statistical power to rule out the possibility of a difference between the two groups.

CONCLUSIONS

Within their limits, the present results indicate the following: 1) the clinical improvements obtained following treatment with EMD or GTR can be maintained over a period of 8 years; and 2) further studies of much higher power need to be performed to support equivalence.

Growth factor delivery for oral and periodontal tissue engineering

The treatment of oral and periodontal diseases and associated anomalies accounts for a significant proportion of the healthcare burden, with the manifestations of these conditions being functionally and psychologically debilitating. Growth factors are critical to the development, maturation, maintenance and repair of craniofacial tissues, as they establish an extracellular environment that is conducive to cell and tissue growth. Tissue-engineering principles aim to exploit these properties in the development of biomimetic materials that can provide an appropriate microenvironment for tissue development. These materials have been constructed into devices that can be used as vehicles for delivery of cells, growth factors and DNA. In this review, different mechanisms of drug delivery are addressed in the context of novel approaches to reconstruct and engineer oral- and tooth-supporting structures, namely the periodontium and alveolar bone.

Position Paper: Periodontal Regeneration

Untreated periodontal disease leads to tooth loss through destruction of the attachment apparatus and tooth-supporting structures. The goals of periodontal therapy include not only the arrest of periodontal disease progression,but also the regeneration of structures lost to disease where appropriate. Conventional surgical approaches (e.g., flap debridement) continue to offer time-tested and reliable methods to access root surfaces,reduce periodontal pockets, and attain improved periodontal form/architecture. However, these techniques offer only limited potential towards recovering tissues destroyed during earlier disease phases. Recently, surgical procedures aimed at greater and more predictable regeneration of periodontal tissues and functional attachment close to their original level have been developed, analyzed, and employed in clinical practice. This paper provides a review of the current understanding of the mechanisms, cells, and factors required for regeneration of the periodontium and of procedures used to restore periodontal tissues around natural teeth. Targeted audiences for this paper are periodontists and/or researchers with an interest in improving the predictability of regenerative procedures. This paper replaces the version published in 1993.

Regeneration of class II furcation defects: determinants of increased success

One of the most important indications for guided tissue regeneration (GTR) treatment is class II furcation lesion. However, periodontal regeneration of this type of defect, although possible, is not considered totally predictable, especially in terms of complete bone fill. Many factors may account for variability in the response to regenerative therapy in class II furcation. The purpose of this review is to assess the prognostic significance of factors related to the patient (smoking, stress, diabetes mellitus, acquired immunodeficiency syndrome and other acute and debilitating diseases, and the presence of multiple deep periodontal pockets), local factors (furcal anatomy, defect morphology, thickness of gingival tissue and tooth mobility), surgical treatment (infection control, bone replacement grafts combined with barriers or GTR alone, type of barrier and surgical technique), and postoperative period (plaque control, membrane exposure, membrane retrieval and a regular supportive periodontal care program) for successful of GTR in class II furcations.

Five-year results of guided tissue regeneration in combination with deproteinized bovine bone (Bio-Oss) in the treatment of intrabony periodontal defects: a case series report

The aim of this study was to report on the clinical and radiographic results 5 years following treatment of intrabony defects with guided tissue regeneration (GTR) in combination with deproteinized bovine bone (DBB) (Bio-Oss). Fifteen patients, with at least one intrabony periodontal defect with probing pocket depth (PPD)>or=7 mm and radiographic presence of an intrabony component (IC)>or=4 mm, were treated with a PLA/PGA bioabsorbable membrane. Prior to placement of the membrane, the defect was filled with DBB impregnated with gentamicin sulfate 2 mg/ml. Standardized intraoral radiographs were taken prior to treatment and at the control examinations after 1 and 5 years. At baseline, the average PPD was 9.2+/-1.1 mm, and the average probing attachment level (PAL) was 10.1+/-1.6 mm; the radiographic bone level (RBL) was 10.4+/-2.45 mm, and an IC of 6.2+/-2.3 mm was present. One year after membrane placement, treatment had resulted in a PAL gain of 3.8+/-1.8 mm, a residual PPD of 4.2+/-1.3 mm, an RBL gain of 4.7+/-2.0 mm, and a residual IC of 2.1+/-1.2 mm. At the 5-year examination, two patients did not show up, and two patients had lost the treated tooth. However, both teeth were endodontically treated, and progressive periodontal destruction might not necessarily have been the reason for extraction. At the 5-year control (11 patients), the PAL gain was 4.1+/-1.6 mm, and the residual PPD was 4.6+/-1.2 mm; an RBL gain of 4.9+/-2.7 mm and a residual IC of 1.8+/-0.8 mm were observed. Statistically significant clinical improvements had occurred between baseline and the 1- and 5-year controls, whereas there were no significant differences between the 1- and 5-year results. The results of GTR with bioabsorbable membranes in combination with Bio-Oss in the treatment of periodontal intrabony defects are basically stable on a long-term basis.

Long-term stability of periodontal conditions achieved following guided tissue regeneration with bioresorbable membranes: case series results after 6-7 years

OBJECTIVES

To evaluate the results of guided tissue regeneration (GTR) treatment of intrabony defects with bioresorbable membranes after 6-7 years, and to disclose factors that may influence the long-term outcome of the treatment.

METHODS

Twenty-five defects in 19 patients were treated by means of polylactic acid/citric acid ester copolymer bioresorbable membranes. At baseline and after 1 and 6-7 years, the following parameters were recorded: (1) probing pocket depth (PPD), (2) gingival recession (REC), (3) probing attachment level (PAL)=PPD+REC, (4) presence/absence of plaque (PI), (5) presence/absence of bleeding on probing (BOP). Smoking habits and frequency of dental-control visits were also recorded. Significance of differences between categorical variables was evaluated with McNemar's test, and between numerical variables with the t-test for paired observations. Generalized linear models were constructed to evaluate the influence of various factors on PAL gain and PPD changes from 1 to 6-7 years. Association of smoking, frequency of dental controls, oral hygiene, and BOP with sites losing > or =2 mm in PAL was evaluated with Fisher's exact test.

RESULTS

At baseline, a mean PPD of 8.7+/-1.1 mm and a mean PAL of 9.8+/-1.5 mm was recorded. Statistically significant clinical improvements were observed at 1 and 6-7 years after GTR treatment. An average residual PPD of 3.8+/-1.1 mm and a mean PAL gain of 3.8+/-1.4 mm were observed after 1 year. After 6-7 years the corresponding values were 4.7+/-1.3 and 3.6+/-1.4 mm, respectively. There were no statistically significant differences between the 1- and the 6-7-year values. At the 6-7-year control, only 16% of the sites had lost > or =2 mm (maximum 3 mm), of the PAL gain obtained 1 year after GTR treatment. None of the sites had lost all of the attachment gained 1 year after treatment. Smoking, frequency of dental controls, oral hygiene, and BOP did not seem to influence the change of PPD and PAL gain, or the stability of PAL gain (i.e. losing PAL or not) from 1 to 6-7 years from treatment.

CONCLUSION

Clinical improvements achieved by GTR treatment of intrabony defects by means of bioresorbable membranes can be maintained on a long-term basis.

Long-Term Tooth Survival Following Regenerative Treatment of Intrabony Defects

BACKGROUND

The longevity of the clinical benefits of guided tissue regeneration (GTR) has not been fully explored. The aim of this investigation was to assess the long-term survival of GTR treated sites in terms of clinical attachment level (CAL) stability and tooth loss.

METHODS

A total of 175 patients with one deep intrabony defect were selected for a retrospective investigation of tooth retention and CAL stability. All sites had been treated with GTR more than 2 years previously and had received full periodontal examinations every 2 years for up to 16 years. Definitions of events for survival analyses were tooth loss, loss of > or = 2 mm compared with the CAL observed before GTR treatment, and loss of > or = 2 mm compared with the CAL observed 1 year after completion of GTR.

RESULTS

Teeth were severely compromised by the presence of CAL loss of 10.7 +/- 2.4 mm, probing depths of 8.7 +/- 2.3 mm and deep intrabony defects (average depth 6.6 +/- 2.1 mm). After GTR, CAL gains were 4.6 +/- 2 mm. Average follow up was 8 +/- 3.4 years; 66.9% of subjects strictly complied with a periodontal maintenance program. Tooth survival was greater than 96% more than 10 years after GTR. CAL was equal or coronal with respect to pretreatment in 92% of cases followed for 15 years after treatment, while loss of CAL compared to the 1-year post-GTR result was observed in 37.8% of cases. Cox proportional hazard models indicated that incidence-free survival was negatively affected by smoking and positively affected by full compliance with a periodontal maintenance program in a specialist practice.

CONCLUSIONS

Within the limits of this study, data suggest that tooth retention and clinical improvements following GTR treatment of intrabony defects can be maintained long term in the great majority of cases and thus that regenerative periodontal treatment represents an important alternative for the management of severely compromised teeth.

Susceptibility of GTR-regenerated periodontal attachment to ligature-induced periodontitis. An experiment in the monkey

AIM

This study aimed to compare the susceptibility of guided tissue regeneration (GTR)-regenerated periodontal attachment to ligature-induced periodontitis with that of the pristine periodontium.

METHODS

Periodontal breakdown was produced in four monkeys by the placement of orthodontic elastics around experimental teeth (test teeth). During a flap operation, the root surfaces were scaled and planed, and a notch indicating the apical termination of scaling and root planing was made in the root surface. Following resection of the crowns and endodontic treatment, an e-PTFE membrane was adapted over the roots. Subsequently, the flaps were sutured to complete closure of the wound (submerged). At membrane removal after 5 weeks, the crowns of the contralateral teeth serving as controls were resected, and the roots treated endodontically during a flap operation. Artificial composite crowns were then placed on both test and control roots. After 3 months of tooth cleaning, cotton floss ligatures were placed passively around both test and control teeth for a period of 6 months. Two weeks later the animals were sacrificed.

RESULTS

Histological analysis demonstrated that the instrumented root surfaces of the test teeth were covered by newly formed cementum of the reparative, cellular, extrinsic and intrinsic fiber type, while the cementum on the controls was mainly acellular extrinsic fiber cementum. Histometric assessments demonstrated that similar attachment loss had occurred on test (1.0+/-0.5 mm) and control roots (1.0+/-0.4 mm) during the 6 months of ligature-induced plaque accumulation.

CONCLUSION

The results indicate that teeth with a periodontal attachment apparatus formed by GTR is not more susceptible to periodontitis than those with a pristine periodontium.

Guided Tissue Regeneration for the Treatment of Periodontal Intrabony and Furcation Defects.A Systematic Review

BACKGROUND

Many clinical studies have demonstrated that guided tissue regeneration (GTR) is a successful treatment modality of periodontal reconstructive surgery and it has become an accepted procedure in most periodontal practices.

RATIONALE

The purpose of this structured review was to assess the efficacy of guided tissue regeneration (GTR) procedures in patients with periodontal osseous defects compared with surgical controls on clinical, radiographic, adverse, and patient-centered outcomes. It extends the scope of previous GTR systematic reviews, which were limited to randomized controlled studies, by the scope of outcome measures examined, and the duration of the study.

FOCUSED QUESTION

In patients with periodontal osseous defects, what is the effect of physical barriers compared with surgical controls on clinical, radiographic, adverse, and patient-centered outcomes?

SEARCH PROTOCOL

An electronic search of the Cochrane Oral Health Group Trials Register and MEDLINE databases was performed. Manual searching of journals included Journal of Clinical Periodontology, Journal of Periodontology, and Journal of Periodontal Research up to January 2002. This manual search also included review of relevant bibliographies. Two manufacturers of GTR devices were contacted regarding unpublished data.

SELECTION CRITERIA

INCLUSION CRITERIA

Studies were selected for review if the evidence level was 3B (cohort) or above, at least 6 months duration, and compared a test GTR intervention with a surgical control.

EXCLUSION CRITERIA

Studies with experimental design problems; histologic or microbiological investigations; or those with outcome measurements, study populations, or study duration not consistent with the inclusion criteria were excluded. Primary outcome measures for intrabony defects were: clinical attachment level (CAL) gain, probing depth reduction (PD), gingival recession (REC) reduction; for furcation defects: vertical probing attachment level (VPAL) gain, vertical probing depth reduction (VPD), horizontal probing depth reduction (HPD), horizontal open probing attachment level gain (HOPA), and vertical open probing attachment level gain (VOPA). Meta-analysis was performed to compare GTR procedures to other surgical treatments and to examine the resulting clinical outcomes.

MAIN RESULTS

1. For the primary outcome variables, in both intrabony-defect and furcation-defect studies, GTR was favored over open flap debridement (OFD) therapies (P < 0.0001). 2. No differences were detected among barrier types, but barrier types could explain some heterogeneity in the results. 3. Augmentation of the GTR barrier with a particulate graft enhanced VPD (P < 0.05), VPAL, and HOPA, but none of the intrabony outcomes.

REVIEWER'S CONCLUSIONS

Overall, GTR is consistently more effective than OFD in the gain of clinical attachment and probing depth reduction in the treatment of intrabony and furcation defects.

Wound healing of degree III furcation involvements following guided tissue regeneration and/or Emdogain®

BACKGROUND

The use of enamel matrix proteins (EMD) has been recently introduced as a new treatment alternative for periodontal regeneration. However, no histological studies are available investigating the effect of EMD in the treatment of degree III furcation involvements.

OBJECTIVES

The aim of this study was to evaluate the healing of mandibular degree III furcation involvements histologically following treatment with guided tissue regeneration (GTR), EMD and a combination of EMD and GTR.

MATERIAL AND METHODS

Degree III furcation involvements were surgically created at the teeth 36, 37, 46, 47 in three monkeys (Macaca fascicularis). Spontaneous healing of the defects was prevented by placing impression material into the defects. After 6 weeks, full-thickness flaps were elevated at the buccal and lingual aspect of the experimental teeth. Following removal of all granulation tissue from the furcation defects, scaling/root planing and conditioning of the root surfaces with 24% EDTA gel, the defects were treated with one of the following treatment modalities: (i) EMD, (ii) GTR or (iii) a combination of EMD and GTR. The defects serving as control did not receive any treatment, except from complete coverage with coronally displaced flaps. After 5 months of healing, the animals were killed and perfused with 10% buffered formalin for fixation. The experimental teeth with surrounding tissues were dissected free, decalcified in EDTA, dehydrated and embedded in paraffin. 8 microm thick histological sections were cut and stained and subsequently examined under the light microscope.

RESULTS

The histological analysis revealed that with GTR or combined EMD and GTR treatment, new attachment formation (new cementum with inserting collagen fibers) had occurred on almost the entire circumference of the furcation and new bone was almost filling the defect in the situations where the membrane was not exposed. The sites treated only with EMD exhibited new attachment and new bone formation to a varying extent, while the control sites presented only limited new attachment and bone formation.

CONCLUSION

The results provided histological evidence suggesting that both GTR and EMD may result in true periodontal regeneration, and suggest that this type of healing might be favored by such treatments in comparison with flap surgery.

Supportive periodontal care: the effect of periodic subgingival debridement compared with supragingival prophylaxis with respect to clinical outcomes

BACKGROUND

The programme of supportive periodontal care (SPC) is essential to the long-term stability of patients with chronic periodontitis. The clinical strategy for SPC is often determined according to 'clinical needs' of the patient and is thus determined by clinical observation and individual decision-making rather than being based on the best available clinical evidence.

OBJECTIVE

To evaluate the effectiveness of supragingival prophylaxis vs. sub-gingival debridement for SPC following the treatment of chronic periodontitis.

SEARCH STRATEGY

Computerized for Medline and the Cochrane Oral Health Group Specialty Trials Register. Hand searching of the Journals of Clinical Periodontology, Periodontal Research and Periodontology. Reference lists from relevant articles were scanned and the authors of eligible studies were contacted to obtain additional information.

SELECTION CRITERIA

Studies were selected if they were designed as a prospective clinical trial in which patients with chronic periodontitis had followed a programme of SPC, which included at least one of the regimens of interest in part of the mouth, for a minimum of 12 months.

DATA COLLECTION AND ANALYSIS

Information regarding methods, patients, interventions (SPC), outcome measures and results were extracted independently, in duplicate, by two reviewers (P.A.H., G.McC.). Absent data were recorded as such and incomplete data were sought from the researchers wherever possible.

RESULTS

In all, 28 papers were identified by the manual and electronic searches; 11 papers were eligible for inclusion. Only one study reported a direct comparison of the two SPCs of interest. The data were reported as mean changes in probing depth and attachment level between baseline and the 12-month follow-up point. For coronal scaling DeltaPD = 0.59 mm [0.13], DeltaAL = -0.13 mm [0.19]. For subgingival debridement DeltaPD = 0.37 mm [0.15], DeltaAL = -0.14 mm [0.18]. There were no significant differences between the SPC regimens. The weighted mean DeltaPD [95% confidence intervals] for the five additional studies that reported supragingival prophylaxis as the SPC regimen was 1.15 mm [-0.17, 2.38]. The weighted mean DeltaPD [95% confidence intervals] for the four studies that reported subgingival debridement as the SPC regimen was 0.56 mm [0.37, 1.47]. The difference between the SPC treatments for the mean DeltaPD is therefore 0.23 mm. The confidence interval for the combined studies was very wide [0.37, 1.47] and very little additional information is gained unless some strong assumptions are made about the comparability of the populations from which the samples are drawn. Such an assumption was not considered appropriate. The weighted mean DeltaAL [95% confidence intervals] for the six additional studies that reported supragingival prophylaxis as the SPC regimen was 0.18 mm [-0.38, 0.74]. The weighted mean DeltaAL [95% confidence intervals] for the six additional studies that reported supragingival prophylaxis as the SPC regimen was 0.50 mm [0.11, 0.89]. The difference between the SPC treatments for mean DeltaAL is 0.32 mm. The confidence interval [-0.36, 1.00] is very wide and the data from the additional studies provide little extra information than that reported in the one study that compared the treatments directly.

CONCLUSION

It is not possible to make any firm recommendations regarding clinical practice based on the crude meta-analysis and the review of these 11 studies. The best available evidence indicates that SPC regimens of supragingival prophylaxis and subgingival debridement are comparable with respect to the clinical outcomes of probing depth and attachment levels at 12 months post non-surgical treatment.

Long-term results of guided tissue regeneration therapy in the treatment of class II furcation defects: a randomized clinical trial

BACKGROUND

The purpose of this study was to evaluate the results after guided tissue regeneration (GTR) using a bioabsorbable membrane in Class II furcation defects in mandibular molars over a 24-month period.

METHODS

Nine patients with 2 comparable Class II furcation defects were included. The defects in each patient were randomly assigned to either test (GTR) or control (open flap debridement) group. Clinical measurements and standardized radiographs were taken at baseline, and at 6, 12, 18, and 24 months. The radiographs were analyzed by subtraction radiography.

RESULTS

There were significant probing depth reductions for both test and control groups (P < 0.007, P < 0.0005, respectively); however the differences between groups were not significant at any examination. The intra-group and inter-group differences in the vertical clinical attachment level gain were not significant (P > 0.05). Over 24 months, a significant horizontal clinical attachment level gain was observed in the test group compared to control (P<0.03). In the test group, 2 sites showed complete closure, one was converted to Class I, and one tooth was lost due to root resorption. In the control group, 2 defects progressed to Class III over 24 months. At 6 months, the test group showed 0.14 mm of bone loss while the control group showed 0.86 mm of bone gain (P = 0.035). The inter-group differences were not significant at 12, 18, and 24 months. A significant bone height gain was observed in the test group at 24 months when compared to the values obtained after 6 months (P = 0.015).

CONCLUSION

GTR may provide a greater horizontal clinical attachment level gain with the possibility of complete closure of some defects and stability over time.

Guided tissue regeneration in intrabony defects using an experimental bioresorbable polydioxanon (PDS) membrane. A 24-month split-mouth study

AIM

The comparison of the clinical, radiographic, and microbiological healing results in deep intrabony defects following GTR therapy with two different bioresorbable membranes in a prospective split-mouth design.

MATERIAL AND METHODS

31 pairs of contralateral intrabony defects were randomly treated with either an experimental Polydioxanon (PDS) membrane or a Polylactic acid (PLA) matrix barrier. After 6, 12 and 24 months, healing results were assessed using clinical examinations (REC, PPD, CAL, vertical relative attachment gain V-rAG), quantitative digital subtraction radiography (amount and area of bone density changes), and microbiological analysis.

RESULTS

Postoperative membrane exposures occurred in 14 PDS and 2 PLA treated sites. 6, 12 and 24 months p.o., both membranes provided a significant gain in CAL [median values: 6 months (PDS vs. PLA: 3.0 vs. 3.0 mm); 12 and 24 months (PDS vs. PLA: 4.0 vs. 4.0 mm)], which corresponded to a V-rAG of 57.1% (PDS) vs. 62.5% (PLA) after 24 months. PDS and PLA treated sites revealed significant bone density gain 6, 12 and 24 months after surgery. 38.8% (PDS) vs. 41.8% (PLA) of the initial defect areas showed bone density gain. While the gain in bone density was significantly greater in PDS than in PLA sites, neither CAL gain nor the area of bone density changes revealed significant differences. Microbiological culture revealed similar bacterial loads in PDS and PLA sites during the first 12 months.

CONCLUSION

This 24-month study indicates that the PDS and PLA membranes can provide similar favorable regeneration results in deep intrabony periodontal defects, although considerably more postoperative membrane exposures have to be expected in PDS treated sites.

Treatment of intrabony defects with enamel matrix proteins or bioabsorbable membranes. A 4-year follow-up split-mouth study

BACKGROUND

Treatment with enamel matrix proteins (EMD) and guided tissue regeneration (GTR) with bioabsorbable membranes has been shown to promote periodontal regeneration; however, until now, there were only limited data on the long-term clinical results following these regenerative techniques. Therefore, the aim of the present study was to present the 4-year results following treatment of intrabony defects with EMD or guided tissue regeneration (GTR).

METHODS

Twelve patients, each displaying one pair of intrabony defects located contralaterally in the same jaw, were randomly treated with EMD or with GTR by means of bioabsorbable membranes. The following clinical parameters were evaluated at baseline, at 1 year, and at 4 years after treatment: plaque index (P1), gingival index (G1), bleeding on probing (BOP), probing depth (PD), gingival recession (GR), and clinical attachment level (CAL). The primary outcome variable was CAL. No statistically significant differences between the groups were found at baseline. Power analysis to determine superiority of EMD treatment showed that the available sample size would yield 70% power to detect a 1 mm difference.

RESULTS

The sites treated with EMD demonstrated mean CAL change from 9.8 +/- 2.0 mm to 6.4 +/- 1.6 mm (P<0.001) and to 6.8 +/- 1.8 mm (P<0.001) at 1 and 4 years, respectively. No statistically significant differences were found between the CAL mean at 1 and 4 years postoperatively. The sites treated with GTR showed a mean CAL change from 9.8 +/- 2.3 mm to 6.6 +/- 1.7 mm (P<0.001) at 1 year and to 6.9 +/- 1.8 mm (P<0.001) at 4 years. The CAL change between I and 4 years did not present statistically significant differences. No statistically significant differences in any of the investigated parameters were observed at 1 and 4 years between the treatment groups.

CONCLUSIONS

It was concluded that the CAL gain obtained following treatment with EMD or GTR can be maintained over a 4-year period.

Longitudinal comparison of the periodontal status of patients with moderate to severe periodontal disease receiving no treatment, non-surgical treatment, and surgical treatment utilizing individual sites for analysis

BACKGROUND

The progression of periodontal disease without treatment and the response of existing periodontal disease to various types of treatment have been studied extensively. Many past studies have used the mean of the patient's probing depths or attachment levels to evaluate disease progression as opposed to following changes in individual sites or teeth. The purpose of the current study was to evaluate the response of individual teeth to treatment or non-treatment.

METHODS

The records from a private periodontal practice were reviewed to find patients with complete periodontal examinations that were recorded at least 1 year apart. Patients who fit these criteria were divided into those who had none of the recommended treatment (untreated, n = 30); those who had only non-surgical treatment (partially treated, n = 20); and a control group who had completed all recommended treatment (surgically treated, n = 41). The data for each tooth of each patient were placed in a database and analyzed using the method of generalized estimating equations (GEE) to test for associations between increase or decrease in probing depths and various initial clinical parameters while adjusting for significant confounders.

RESULTS

Teeth that received no treatment or non-surgical treatment showed significant increases in probing depths, worsening of prognosis, worsening of furcation involvement, and increases in mobility when compared to surgically treated teeth. Teeth that received surgical treatment showed significant decreases in probing depths. No significant difference was noted between teeth that had no treatment and teeth that had non-surgical treatment.

CONCLUSIONS

When individual teeth are used as the basis for analysis, teeth that receive no treatment or non-surgical treatment show a significant worsening of probing depths, furcations, mobility, and prognosis when compared to teeth that receive surgical treatment, while surgically treated teeth show significant improvement in probing depths.

PMN responses following use of 2 biodegradable GTR membranes

OBJECTIVES

In the present prospective trial, the PMN response following resorbable GTR barrier placement was evaluated in mandibular class II furcation lesions.

MATERIALS AND METHODS

In 10 patients with treated chronic periodontitis, we randomly selected the 1st molars in the mandible with buccal degree II furcation involvement for either polylactic-citric-acid-ester (PLA) or glycolide-lactic-copolymer (PGL) GTR membrane therapy. We examined contralateral healthy molar sites as untreated controls. We then evaluated the PMN-derived inflammatory tissue response at baseline, weekly up to 6 weeks post-therapy and at 12 and 24 weeks using GCF myeloperoxidase (MPO), beta-glucuronidase (betaG) and beta-N-acetyl-hexosaminidase (betaNAH).

RESULTS

The enzyme levels increased from baseline to the 6-week examination. After the 6-week reappointment, enzyme levels dropped reaching the baseline scores at both the 12- and 24-week visit. At PGL sites, the enzyme levels decreased earlier. Compared with healthy control sites, the MPO, betaNAH and betaG tests revealed different maximum levels at week 2 and 3 (PGL) and week 4, 5 and 6 (PLA). For both of the barriers the clinical parameters revealed a sustained improvement following therapy.

CONCLUSION

The release of PMN enzymes following placement of bioabsorbable membranes reflects the early soft tissue healing process. Our results suggest that the PMN response is barrier-dependent with the maximum response occuring at different times. However, the host response did not measureably affect the course of clinical healing.

The effect of hyaluronan on bone and soft tissue and immune response in wound healing

BACKGROUND

The aims of this study were to investigate the anti-inflammatory effect and the effect on bone regeneration of hyaluronan in surgical and non-surgical groups.

METHODS

In each of 15 individuals, 2 teeth with defects of similar character and magnitude in the upper or lower jaw were chosen. There were at least 2 teeth between the test and the control sites. In the surgical group, a bioabsorbable membrane was used for both test and control sites, and hyaluronan was placed in the intrabony pocket of the test site. In the non-surgical group, the periodontal pockets were scaled and hyaluronan was administered 3 times with an interval of 1 week in the test pockets. Alveolar bone height and bone healing patterns were analyzed using digital intraoral radiographs. Measurements of bone height were performed in the original digital black-and-white radiographs to obtain quantitative data on bone gain or loss. Bone healing patterns were studied with color-coded radiographs, using specially designed software in a personal computer with subsequent combinations of radiographs. Gingival crevicular fluid immunoglobulin (Ig)G, C3, and prostaglandin E2 (PGE2) responses; periodontal probing depth; bleeding on probing; and the presence of plaque were studied to evaluate the anti-inflammatory effect. Data were obtained at baseline before treatment, and at 2 weeks, and 1, 3, 6, and 12 months after treatment.

RESULTS

For the surgical treatments, bone height was increased in the test group treated with hyaluronan (mean value 2.2%, corresponding to an average increase of approximately 0.5 mm) and reduced in the control group (mean value -1.8%, corresponding to an average decrease of approximately - 0.4 mm) (P<0.05) after 12 months. For the non-surgical treatments, bone height was reduced by a mean value of -1.1% (corresponding to an average decrease of approximately -0.25 mm) in the test group treated with hyaluronan and -3.3% (corresponding to an average decrease of approximately -0.75 mm) in the control group after 12 months (N.S.). According to the digital color-coded radiographs, the test sites in the surgical and non-surgical groups showed apposition of bone minerals. Immune responses showed no differences during the 12 months studied for the surgical and non-surgical sites. Mean periodontal probing depths were reduced between 2.5 mm and 4.1 mm in the surgical and non-surgical groups.

CONCLUSIONS

The observed difference in bone height between test and control sites in the surgical group after 12 months was less than 1 mm, which was only detectable on radiographs. No statistical difference was found on radiographs in the non-surgical group, where a decrease in bone height was found for both groups after scaling. Probing depth reduction after the surgical treatment, as well as after scaling and root planing, was as expected. Hyaluronan in contact with bone and soft tissues had no influence on the immune system in this study. Further studies are needed to determine the extent to which hyaluronan can lead to clinically significant healing of periodontal lesions.

Flow cytometry analysis of guided tissue regeneration-associated human periodontal cells

BACKGROUND

Expanded polytetrafluoroethylene (ePTFE) barrier membranes have been widely used for guided tissue regeneration (GTR) of the human periodontal ligament (PL). However, the precise cellular and molecular events involved in the re-growth of the new tissue are still unclear.

METHODS

Retrieved membranes and the newly-regenerated soft tissue (RT) underlying the membranes were used to examine the cells associated with GTR compared with normal human PL and gingival cells. Flow cytometry (FCM) was used, for the first time, to analyze the spindle-shaped fibroblast-like cells which were adherent to these membranes and the cells which grew out of the RT.

RESULTS

The results showed that the membrane-associated (M) cells had the lowest rate of proliferation and appeared to be larger and more granular than the other types of cell. Moreover, both the M- and RT-derived cells were found to express higher levels of the extracellular matrix (ECM) proteins collagen type 1, fibronectin, tenascin, and decorin. In addition, evidence based on FCM profiles identified distinct sub-populations of GTR cells in which fibronectin expression was markedly up-regulated compared with normal PL cells and which also differed in size and granularity.

CONCLUSIONS

The results of this study show that cells associated with GTR barrier membranes and with the underlying tissue appear to have distinct phenotypic and functional activities consistent with the production of new periodontal connective tissue and periodontal regeneration.

Interleukin-1 gene polymorphisms and long-term stability following guided tissue regeneration therapy

BACKGROUND

Specific interleukin (IL)-1 gene polymorphisms are associated with an increased susceptibility to severe periodontitis, increased inflammation, and increased likelihood of tooth loss during the maintenance phase after conventional periodontal therapy. The aim of the present study was to evaluate the impact of genotype on the maintenance of gained clinical attachment obtained after guided tissue regeneration (GTR) surgical therapy in deep intrabony defects.

METHODS

Forty deep (> or =4 mm) interproximal angular bony defects with presurgical clinical attachment loss of >8 mm were treated by GTR using a non-absorbable expanded polytetrafluoroethylene (ePTFE) membrane. Membranes were surgically removed 4 to 6 weeks after surgery. Afterwards patients were placed on monthly recall for the first year and every 3 months for the following 3 years. At the 4-year re-evaluation, a IL-1 genetic susceptibility test was performed on all patients.

RESULTS

Fourteen (35% of the 40 patients) were genotype-positive (+). At baseline no statistically significant differences were found between patients with different genotypes in full mouth plaque score (FMPS), full mouth bleeding score (FMBS), clinical attachment level (CAL), probing depth (PD), or gingival recession. At year 1 follow up visit, no statistically significant differences were noted between genotype + and genotype - patients in FMPS, FMBS, amount of CAL gain, decrease in PD, or increase in gingival recession. Sixteen patients had membrane exposure after the GTR procedures. In these patients, the amount of CAL gain (P <0.001) and PD reduction (P <0.01) 1 year after surgery was significantly lower than those observed in patients without membrane exposure. At the year 4 follow-up visit, no significant differences were found between genotype negative and positive patients in FMPS or FMBS and both groups showed a significant loss in CAL (P<0.001) and increase in PD (P<0.001) when compared to year 1 visit. No change in gingival recession was noted. Genotype + patients showed significantly more CAL loss (P<0.002) and increase in PD (P<0.001) between the years 1 and 4 when compared to genotype - patients. A significant association between genotype and stability of the regenerated attachment was also demonstrated.

CONCLUSIONS

The results of this study demonstrate that genotype expression did not effect GTR treatment response at 1 year, but had a great impact on long-term stability (year 4). In a 3-year period, patients with positive IL-1 genotype lost about 50% of the first year gained CAL and were about 10 times more likely of experiencing > or = 2 mm CAL loss when compared to oral hygiene matched genotype-negative patients.

Long-term clinical outcomes of abutments treated with guided tissue regeneration

STATEMENT OF PROBLEM

Guided tissue regeneration (GTR) is an efficacious and predictable treatment modality for deep intrabony defects around natural teeth and abutments. However, long-term prognosis of abutments treated with regeneration has to be proven.

PURPOSE

This study investigated the long-term stability of clinical outcomes obtained with regeneration in strategically important abutments.

MATERIAL AND METHODS

Sixteen deep intrabony defects around strategically important abutments in 16 patients were treated according to the principles of GTR. After completion of initial periodontal therapy and placement of long-term provisional fixed partial dentures, nonresorbable membranes were applied. Membranes were removed after 6 weeks. All patients remained in a supervised recall program. Final fixed partial dentures were placed 1 year after surgery. Clinical outcomes were evaluated at 1 year and then 4 to 8 years after surgery.

RESULTS

Clinical attachment level gains of 5.3 +/- 1.8 mm, reductions in pocket depth (6.1 +/- 2 mm), and increases in the percentage of radiographic bone support (31% +/- 18%) were observed at 1 year. At long-term follow-up visits, clinical attachment levels remained stable with respect to 1 year (-0.1 +/- 0.6 mm; P =.4). The percentage of radiographic bone support slightly increased as compared with 1 year (1% +/- 3%, P =. 04), and pocket depths (0.8 +/- 0.8 mm, P =.004).

CONCLUSIONS

This study indicated that tooth support can be gained with GTR and maintained over time in patients recalled regularly.

Lectins inhibit periodontal ligament fibroblast attachment, spreading and migration on laminin substrates

The ways in which carbohydrate signals from the extracellular matrix influence the responses of periodontal ligament (PDL) fibroblasts are essentially unknown. The purpose of this study, using video digital image analysis, was to examine the effects of lectins on the attachment, spreading and migrational responses of rat periodontal ligament fibroblasts on the highly glycosylated glycoprotein laminin (LN) in vitro. PDL fibroblasts were isolated from rat molar teeth and grown in culture. Bound LN and control substrates (bovine serum albumin and untreated plastic) were incubated with solutions of either wheatgerm agglutinin (WGA), specific for N-acetylglucosamine, or concanavalin A (ConA), specific for mannose, in 96-well plates. Unbound lectin was rinsed away and 10.0 x 10(3) cells were seeded per well and allowed to attach for 1.5 h. Incubation of LN substrates with WGA, prior to the addition of any cells, inhibited PDL fibroblast binding more than 5-fold. ConA, however, had no effect on cell binding but inhibited mean individual cell spreading nearly 3-fold under similar assay conditions. The effects could be prevented by adding each lectin's respective specific sugar. The lectins had no effects on the control substrates. In a 24-h cell migration assay WGA and ConA both significantly inhibited migration of PDL fibroblasts. It is likely that WGA inhibited cell attachment and cell migration, by binding to oligosaccharides and blocking access to adjacent polypeptide cell recognition sequences on LN. The results from the ConA experiments, where binding was allowed but spreading was severely inhibited, suggest a possible informational role for the carbohydrates present on LN.

Long-term stability of the mucogingival complex following guided tissue regeneration in gingival recession defects

The purpose of the present study was to evaluate the stability of soft tissue conditions in gingival recession defects treated with guided tissue regeneration (GTR). The study population was selected among those patients who had been treated with GTR procedures for Miller's class I or II, deep (> or =3 mm), buccal gingival recession defects. Defects were included only when they had revealed recession depth reduction > or =2 mm and root coverage > or =60% at 6 months following GTR treatment. These defects were regarded as successfully treated and scheduled for further monitoring. 20 patients, 11 male and 9 female, aged 23 to 57 years (mean age: 33.2 years), each contributing 1 defect, were selected. 9 patients were smokers (> or =10 cigarette per day). Recession depth (RD), probing depth (PD), clinical attachment level (CAL), and width of keratinized gingiva (KG) were assessed immediately before surgery, at 6 months post-surgery (baseline examination), and at 4 years post-surgery (4-year examination). At baseline examination, RD reduction was 3.6+/-0.9 mm (mean root coverage: 80%). CAL gain amounted to 4.2+/-1.3 mm, 60% of the defects showing CAL gain > or =4 mm. KG increased from 1.9+/-1.2 mm at presurgery examination to 3.1+/-0.9 mm at baseline examination. At 4-year examination, no significant changes from baseline RD, CAL and KG recordings were observed. Differences in baseline-4 year changes between smokers and non-smokers were not statistically significant. The results of the present study demonstrate that clinical outcome achieved following GTR procedure in gingival recession defects can be maintained over periods up to 4 years.

The use of autogenous periosteal grafts as barriers for the treatment of intrabony defects in humans

The purpose of this study was to evaluate the clinical effectiveness of a connective tissue graft including periosteum used as a barrier for guided periodontal tissue regeneration in interproximal bony defects. An open flap debridement of a comparable interproximal bony defect in the same patient was used as a control. This study was performed at 2 different clinical centers. Six paired defects were treated at one center, and 16 paired defects at the other. Reentry surgeries were performed at 6 months. Preoperative comparisons of control and experimental sites with respect to clinical parameters and osseous measurements were similar. Post-surgical experimental sites produced more gain in clinical attachment (1.25 mm on buccal and 1.25 mm on lingual sites at center A and 1.26 mm on buccal and 1.18 mm on lingual sites at center B) and osseous defect fill (1.84 mm on buccal and 2.00 mm on lingual sites at center A and 1.66 mm on buccal and 2.04 mm on lingual sites at center B) when compared to control sites. The results of this trial indicate that clinical resolution of interproximal periodontal defects can be obtained with periosteal grafts used as barriers.

GTR therapy of intrabony defects using 2 different bioresorbable membranes: 12-month results

This prospective split-mouth study was designed to compare the clinical and radiographic healing results in intrabony periodontal defects 12 months after GTR therapy with 2 different bioresorbable barriers. The study comprised 25 healthy patients with one pair of contralaterally located intrabony defects with a probing pocket depth of > or = 6 mm and radiographic evidence of angular bone loss of > or = 4 mm. The 2 defects of each patient were randomized for treatment either with polylactic acid (PLA) membranes or with polyglactin-910 (PG-910) membranes. The patients received systemic doxycycline (100 mg/d) for 11 days postoperatively. One blinded examiner recorded the following clinical parameters using a pressure calibrated probe at baseline and after 12 months: papillary bleeding index (PBI), gingival recession (REC), probing pocket depth (PPD), and probing attachment level (PAL). The vertical relative attachment gain (V-rAG) was calculated as a % of the PAL gain related to the maximum possible attachment gain (expressed by the intraoperatively measured depth of the osseous defect). Geometrically standardized intraoral radiographs were quantitatively evaluated for bone changes (density, area) in the defect region using digital subtraction radiography (DSR). Clinical and radiographic data were statistically analyzed using the Wilcoxon-signed-rank test (alpha=0.05). Postoperative membrane exposures occurred in 9 PLA and 13 PG-910 treated sites. After 12 months of healing, both barrier types provided significant PPD reductions and PAL gain [median (25/75 percentile)]: deltaPPD [PLA: 3.0 (2.0/4.0) mm; PG-910: 3.0 (2.0/4.5) mm]; deltaPAL [PLA: 3.0 (2.5/4.0) mm; PG-910: 2.0 (1.0/4.0) mm]. V-rAG amounted to 60% in PLA sites and 54% in PG-910 sites. DSR revealed significant bone density gain after 12 months. 58.3% of the initial defect area in PLA sites and 54.0% of the initial defect area in PG-910 sites showed bone density gain. Neither clinical nor radiographic data revealed any significant difference between the 2 barrier types after 12 months. In conclusion, this 12-month study demonstrated that PLA and PG-910 membranes provided similar favorable regeneration results in deep intrabony periodontal defects.