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

Predictive factors of periodontal regeneration outcomes using rhFGF-2: A case-control study

OBJECTIVE

This study aimed to investigate the factors influencing the clinical outcomes of regenerative therapy using recombinant human fibroblast growth factor-2 (rhFGF-2).

BACKGROUND

rhFGF-2 promotes periodontal regeneration, and identifying the factors influencing this regeneration is important for optimizing the effectiveness of rhFGF-2.

METHODS AND MATERIALS

This study used a hospital information-integrated database to identify patients who underwent periodontal regenerative therapy with rhFGF-2. Factors included age, smoking status, diabetes mellitus (DM), periodontal inflamed surface area (PISA) at the initial visit, whether the most posterior tooth was involved or not, and preoperative radiological bone defect angle. Periodontal regenerative therapy outcomes were defined as good if radiographic bone fill ≥35% or periodontal pocket closure at 9-15 months after surgery. Bone fill rate (%) and periodontal pocket depth (mm) were also used as outcome measures. Factors were evaluated by simple regression analysis, and then the association between factors and the outcomes was determined by multivariate analysis.

RESULTS

PISA and age at the first visit did not significantly influence the success or failure of bone fill rate byrhFGF-2. However, DM, radiographic bone defect angle, and the most posterior tooth significantly influenced the regenerative effect (success/failure in bone fill) of rhFGF-2. The most posterior tooth was significantly associated with bone fill rate by rhFGF-2. Examination of the association between pocket closure and factors shows that the most posterior tooth significantly influenced. The most posterior tooth and preoperative PPD were significantly associated with pocket reduction depth. For the most posterior tooth, a significantly higher bone regeneration rate (p < .05) was observed with a combination of autologous bone graft and rhFGF-2 than with rhFGF-2 alone, and the effect was significant in multivariate analysis.

CONCLUSIONS

The radiographic bone defect angle, the involvement of most posterior teeth, and the presence of DM influenced the effectiveness of rhFGF-2 in periodontal regeneration. However, PISA values and age at the initial visit had no significant effect.

Tooth survival and clinical outcomes up to 26 years after guided tissue regeneration therapy in deep intra-bony defects: Follow-up investigation of three randomized clinical trials

AIM

To investigate tooth survival and clinical long-term outcomes up to 26 years following guided tissue regeneration (GTR) therapy in deep intra-bony defects.

METHODS

Patients from three prospective clinical split-mouth studies, which investigated the outcomes of GTR therapy, were re-evaluated 21-26 years after surgery independent of the membrane type used, and tooth survival was assessed according to several site-specific and patient-related factors.

RESULTS

About 50 patients contributing 102 defects were available for this long-term follow-up. After up to 26 years (median 23.3 years), 52.9% of the teeth were still in situ. The median survival of the extracted teeth was 13.8 years. Patients with diabetes mellitus and/or smoking history lost significantly more teeth in the long term. Compared to the 1-year situation, there was no new median CAL loss after up to 26 years in the teeth which were still in situ.

CONCLUSIONS

Within the limitations of this study, our data show that more than 50% of the initially seriously diseased teeth were still in situ up to 26 years following GTR therapy despite an overall limited adherence to SPT. In the majority of these teeth, the CAL gain 1 year after GTR could be maintained over this long period.

Treatment of intrabony defects with guided tissue regeneration in aggressive periodontitis: clinical outcomes at 6 and 12 months

OBJECTIVE

The aim of this study was to compare clinical outcomes between guided tissue regeneration (GTR) and access flap (AF) surgery in patients with aggressive periodontitis (AgP).

METHODS

Eighteen AgP patients with similar bilateral intrabony defects were treated in this split-mouth, single-blinded, randomised, controlled clinical trial. All patients presented with ≥3 mm intrabony defects and ≥5 mm periodontal pocket depths (PPD). In each patient, one defect was treated with a polyglycolide membrane according to the GTR principle, whereas the contralateral side was treated with AF. For both sides, a simplified papilla preservation flap was used. At baseline, 6 and 12 months post-surgery, the clinical attachment levels (CAL) and PPD were evaluated.

RESULTS

At 6 and 12 months, at the GTR sites, the mean [95 % CI] CAL gain was 1.7 mm [1.1, 2.3] and 1.6 mm [0.9, 2.1], respectively, while the mean [95 % CI] PPD reduction was 2.3 mm [1.9, 2.8] and 2.4 mm [1.9, 2.8], respectively. Similar CAL (1.6 mm [1.0, 2.2] and 2.1 mm [1.4, 2.7]) and PPD (2.0 mm [1.5, 2.4] and 2.5 mm [2.0, 3.0]) outcomes were observed at the control sites at 6 and 12 months, respectively. Notably, at the GTR-treated sites, 13 subjects presented with various degrees of membrane exposure.

CONCLUSIONS

Both therapies were effective in the treatment of intrabony defects in AgP patients, and no statistically significant differences between them could be demonstrated, possibly as a result of the differing degrees of membrane exposure at the GTR sites.

CLINICAL RELEVANCE

Both periodontal regeneration and conventional periodontal surgery are effective treatments for AgP patients.

AB, Taba Jr. M, Palioto DB, Grisi MFM, Souza SLS. Treatment of Intrabony Defects with Anorganic Bone Matrix/P-15 or Guided Tissue Regeneration in Patients with Aggressive Periodontitis

Intrabony periodontal defects present a particular treatment problem, especially in patients with generalized aggressive periodontitis (G-AgP). Regenerative procedures have been indicated for this clinical situation. The aim of this study was to compare treatment outcomes of intrabony periodontal defects with either anorganic bone matrix/cell binding peptide (ABM/P-15) or guided tissue regeneration (GTR) in patients with G-AgP. Fifteen patients, with two intrabony defects ≥3 mm deep, were selected. Patients were randomly allocated to be treated with ABM/P-15 or GTR. At baseline and at 3 and 6 months after surgery, clinical and radiographic parameters and IL-1β and IL-6 gingival fluid concentrations were recorded. There was a significant probing pocket depth reduction (p<0.001) for both groups (2.27 ± 0.96 mm for ABM/P-15 group and 2.57 ± 1.06 mm for GTR group). Clinical attachment level gain (1.87 ± 0.94 mm for ABM/P-15 group and 2.09 ± 0.88 mm for GTR group) was also observed. There were no statistically significant differences in clinical parameters between the groups. The radiographic bone fill was more expressive in ABM/P-15 group (2.49 mm) than in GTR group (0.73 mm). In subtraction radiographs, the areas representing gain in density were 93.16% of the baseline defect for ABM/P-15 group versus 62.03% in GRT group. There were no statistically significant differences in inter-group and intra-group comparisons with regards to IL-1β and IL-6 quantification. Treatment of intrabony periodontal defects in patients with G-AgP with ABM/P-15 and GTR improved significantly the clinical outcomes. The use of ABM/P-15 promoted a better radiographic bone fill.

Histological and histomorphometric analysis of animal experimental dehiscence defect treated with three bio absorbable GTR collagen membrane

BACKGROUND

Guided tissue regeneration (GTR) allows mesenchymal cells to repopulate the defects. However, there is limited information regarding the efficacy of different membranes. The present study was designed to histologically and histomorphometrically compare three collagen membranes in regenerative treatment of dehiscence defects in dogs.

MATERIALS AND METHODS

This 8 weeks experimental animal study comprised 4 healthy dogs. 5 × 5 mm periodontal dehiscences were created in each side of the mandible (4 dehiscences in each side of dogs' mandible). In each side, one dehiscence defect was left uncovered as a control site and three other sites were randomly covered with different collagen membranes (Biogide (BG), Biomend (BM), and Cytoplast (CYT)). Histomorphometric and histologic analysis were conducted at 4 and 8 weeks. Data were analyzed using ANOVA, Mann-Withney, Kruskal-Wallis and Fisher 's exact tests (α = 0.05).

RESULTS

According to histomorphometric analysis there was a significant difference between treatment and control groups regarding the bone formation and the distance between the reference point and apical end of junctional epithelium (DJE) (P < 0.05). At 4 weeks, the maximum amount of bone thickness and height was observed in BG and CYT respectively, and this maximum rate was seen with the use of BG at 8 weeks. It was shown that DJE reached its highest rate in BM and CYT at 4 and 8 weeks, respectively. Organized PDL was formed in treatment groups.

CONCLUSION

The membrane-treated groups had a statistically significant increase in bone formation and connective tissue attachment compared to control groups. However, there are some differences among experimental groups, which should be considered in GTR treatments.

An evaluation of a resorbable (semirigid) GTR membrane in human periodontal intraosseous defects: A clinicoradiological re-entry study

AIM

To evaluate the effectiveness of a resorbable, semi rigid guided tissue regeneration (GTR) membrane in the treatment of periodontal intraosseous defects.

SETTINGS AND DESIGN

Randomized controlled clinicoradiological re-entry study.

MATERIALS AND METHODS

Eight patients with bilateral, identical intraosseous defects were selected. The sides for test and control group were randomly allocated to treat either with bioresorbable semi rigid membrane (test group) or open flap debridement (control group). Radiographic analysis was done by comparing intraoral peri apical radiographs taken at baseline and at six months. Extended cone paralleling device with grid was used to standardize radiographs. Auto CAD software was used for the analysis.

STATISTICAL ANALYSIS USED

Paired-t test.

RESULTS

On surgical reentry at six months, the mean reduction in depth of the defect at the test site was 2.63 mm. The mean gain in Relative attachment level was 1.75 mm. The control sites showed a statistically insignificant gain. The mean percentage defect fill assessed on radiographs using auto CAD software was 15.54%.

CONCLUSION

The resorbable, semi-rigid GTR membrane can be effectively used for the treatment of human one-walled angular defects.

The Application of Microencapsulation Techniques in the Treatment of Endodontic and Periodontal Diseases

In the treatment of intracanal and periodontal infections, the local application of antibiotics and other therapeutic agents in the root canal or in periodontal pockets may be a promising approach to achieve sustained drug release, high antimicrobial activity and low systemic side effects. Microparticles made from biodegradable polymers have been reported to be an effective means of delivering antibacterial drugs in endodontic and periodontal therapy. The aim of this review article is to assess recent therapeutic strategies in which biocompatible microparticles are used for effective management of periodontal and endodontic diseases. In vitro and in vivo studies that have investigated the biocompatibility or efficacy of certain microparticle formulations and devices are presented. Future directions in the application of microencapsulation techniques in endodontic and periodontal therapies are discussed.

Digital subtraction radiographic analysis of the combination of bioabsorbable membrane and bovine morphogenetic protein pool in human periodontal infrabony defects

OBJECTIVES

This study assessed the bone density gain and its relationship with the periodontal clinical parameters in a case series of a regenerative therapy procedure.

MATERIAL AND METHODS

Using a split-mouth study design, 10 pairs of infrabony defects from 15 patients were treated with a pool of bovine bone morphogenetic proteins associated with collagen membrane (test sites) or collagen membrane only (control sites). The periodontal healing was clinically and radiographically monitored for six months. Standardized pre-surgical and 6-month postoperative radiographs were digitized for digital subtraction analysis, which showed relative bone density gain in both groups of 0.034 ± 0.423 and 0.105 ± 0.423 in the test and control group, respectively (p>0.05).

RESULTS

As regards the area size of bone density change, the influence of the therapy was detected in 2.5 mm² in the test group and 2 mm² in the control group (p>0.05). Additionally, no correlation was observed between the favorable clinical results and the bone density gain measured by digital subtraction radiography (p>0.05).

CONCLUSIONS

The findings of this study suggest that the clinical benefit of the regenerative therapy observed did not come with significant bone density gains. Long-term evaluation may lead to a different conclusions.

Injectable biomaterials for regenerating complex craniofacial tissues

Engineering complex tissues requires a precisely formulated combination of cells, spatiotemporally released bioactive factors, and a specialized scaffold support system. Injectable materials, particularly those delivered in aqueous solution, are considered ideal delivery vehicles for cells and bioactive factors and can also be delivered through minimally invasive methods and fill complex 3D shapes. In this review, we examine injectable materials that form scaffolds or networks capable of both replacing tissue function early after delivery and supporting tissue regeneration over a time period of weeks to months. The use of these materials for tissue engineering within the craniofacial complex is challenging but ideal as many highly specialized and functional tissues reside within a small volume in the craniofacial structures and the need for minimally invasive interventions is desirable due to aesthetic considerations. Current biomaterials and strategies used to treat craniofacial defects are examined, followed by a review of craniofacial tissue engineering, and finally an examination of current technologies used for injectable scaffold development and drug and cell delivery using these materials.

Stability of Clinical and Radiographic Results After Guided Tissue Regeneration in Infrabony Defects

BACKGROUND

The aim of this 5-year follow-up study was to evaluate clinically and radiographically the long-term results after guided tissue regeneration (GTR) therapy of infrabony defects using non-resorbable and bioabsorbable barriers.

METHODS

Thirty-one patients with periodontitis and 50 infrabony defects that had been treated using GTR were recruited. Eleven defects were treated with non-resorbable expanded polytetrafluoroethylene membranes and 39 defects with bioabsorbable barriers. At baseline and 6 and 60 +/- 3 months after surgery, clinical parameters and standardized radiographs were obtained. During surgery and 60 +/- 3 months thereafter, the distance from the cemento-enamel junction to the base of the bony defect (vertical probing bone level [PBL-V]) was measured. Bone gain was evaluated using digital subtraction radiography.

RESULTS

At 6 and 60 +/- 3 months after GTR, there was a statistically significant (P <0.001) reduction of probing depth (6 months: 4.31 +/- 1.76 mm; 60 months: 3.95 +/- 1.62 mm) and vertical clinical attachment level gains (CAL-V) (6 months: 3.34 +/- 1.66 mm; 60 months: 2.97 +/- 1.53 mm). From 6 to 60 months after GTR, three infrabony defects exhibited CAL-V loss >2 mm, and a small, statistically not significant mean CAL-V loss of 0.39 +/- 1.60 mm was observed. From baseline to 60 +/- 3 months, a significant PBL-V gain of 1.78 +/- 2.67 mm (P <0.001) and increase in bone density were observed (P = 0.003).

CONCLUSION

The CAL-V gain achieved after GTR in infrabony defects using both non-resorbable and bioabsorbable barriers was stable after 5 years in 47 of 50 defects.

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.

Growth factors and cytokines in autologous platelet concentrate and their correlation to periodontal regeneration outcomes

AIM

To determine the concentration of naturally available biologic mediators in autologous platelet concentrates and their correlation with periodontal regeneration outcomes.

MATERIAL AND METHODS

In 25 patients with two intra-bony defects each, an autologous platelet concentrate (APC) was prepared by a laboratory thrombocyte apheresis technique pre-operatively. Both defects were treated using a bioresorbable guided tissue regeneration-membrane in combination with tricalciumphosphate (TCP). In the test defect, APC was additionally applied. In the APC, platelets were counted and the levels of growth factors and cytokines were determined by ELISA. Correlations between the platelet counts or the growth factor/cytokine levels and the potential clinical and radiographic regeneration outcomes due to APC were calculated after 3, 6, and 12 months.

RESULTS

The APC contained 2.2 x 10(6) platelets/mul, which was 7.9 times more than in the venous blood. Transforming growth factor-beta1 (TGF-beta1), insulin-like growth factor-I (IGF-I), platelet-derived growth factor-AB (PDGF-AB), PDGF-BB, vascular endothelial growth factor (VEGF), and epidermal growth factor (EGF) were found in the APC, whereas interleukin-1beta (IL-1beta), IL-6, tumor necrosis factor alpha (TNFalpha), IL-4, and IL-10 were not detectable. The regression analysis showed a weak correlation between the platelet counts or the growth factor levels and the clinical and radiographic regeneration outcomes (r2<or=0.4).

CONCLUSION

Autologous platelet concentrate contains relatively high concentrations of PDGF-AB, PDGF-BB, TGF-beta1, and IGF-I, but their potential influence on periodontal regeneration remains unclear.

Histological study on sinus lift grafting by Fisiograft and Bio-Oss

The work aims to provide a histological investigation of Fisiograft, a PLA/PGA copolymer, used as filler for bone defects in humans. The study was performed on biopsies of sinus lifts where Bio-Oss and Fisiograft gel were applied as graft material. Bone regeneration was satisfactory in all sinus lifts, even when Fisiograft was applied alone. Due to remarkable osteoclast activity, Bio-Oss granules were cleared from the majority of biopsy cores. At histology, Fisiograft gel appeared as globes enveloped by fibroblasts, displaying an epithelial-like cell appearance. Due to its solubility in solvents, undegraded Fisiograft (recorded for 7 months or more) did not stain whereas degraded Fisiograft stained positive. The loose connective tissue, that surrounded Fisiograft and bone contained isolated mastocytes. Bone grew inside the loose connective and often reached the surface of Fisiograft by intervening cells. The results seem to indicate that Fisiograft may be considered both a polymer useful for fastening bone substitutes inside a defect and in addition a material capable of prompting bone regeneration, with or without the use of a bone substitute. In addition to space-former and space-maintainer functions, Fisiograft shows potential bone stimulation function, which may be labelled as osteopromotive capability.

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.

GTR treatment of intrabony defects with PLA/PGA copolymer or collagen bioresorbable membranes in combination with deproteinized bovine bone (Bio-Oss)

The objectives of this study were to evaluate the results of guided tissue regeneration (GTR) treatment of intrabony defects with two kinds of bioresorbable membranes, with deproteinized bovine bone (Bio-Oss) used as an adjunct. Twenty-eight patients with at least one intrabony defect with a probing pocket depth (PPD) >/=7 mm and radiographic evidence of an intrabony component (IC) >/=4 mm were randomly treated with either a polylactic/polyglycolic (PLA/PGA) acid copolymer or a collagen bioresorbable membrane combined with Bio-Oss implantation. Immediately prior to surgery (baseline) and after 1 year, the following parameters were recorded: (1) PPD, (2) gingival recession (REC), (3) probing attachment level (PAL), (4) presence/absence of plaque (PI), and (5) presence/absence of bleeding on probing (BOP). Occurrence of membrane exposure during healing and the smoking habits of the patients were also recorded. Statistical analysis was carried out using chi(2) -tests and t-tests. There were no significant differences between the two membrane groups regarding the clinical parameters at baseline. Statistically significant clinical improvements (PAL gains, reduced PPDs) were observed 1 year after treatment in both groups. There were no significant differences, however, between the PLA/PGA and the collagen membrane groups regarding any of the evaluated parameters (mean PAL gain: 2.9 mm vs 3.9 mm; mean residual PPD: 4.8 mm vs 4.1 mm, respectively). The membrane material per se does not seem to be a critical factor for the outcome of GTR treatment of intrabony defects with bioresorbable membranes.

Guided Tissue Regeneration With Bioabsorbable Barriers. II. Long-Term Results in Infrabony Defects

BACKGROUND

The aim of this 5-year randomized controlled clinical trial was to evaluate the long-term results after guided tissue regeneration (GTR) therapy of infrabony defects using two bioabsorbable barriers.

METHODS

Fifteen pairs of contralateral infrabony defects in 15 patients with moderate to severe periodontitis were treated. Each patient received one polydioxanon (test: T) and one polylactide acetyltributyl citrate (control: C) barrier by random assignment. At baseline, 12, and 60 +/- 3 months after surgery clinical parameters and standardized radiographs were obtained. Vertical bone levels (PBL-V) were measured during surgery and 60 +/- 3 months later by transgingival bone sounding.

RESULTS

Thirteen patients were available for the 60-month examinations. Twelve and 60 +/- 3 months after GTR, statistically significant (P< or =0.001) vertical attachment (CAL-V) gain was found in both groups (T12: 3.5 +/- 1.5 mm; T60: 2.2 +/- 1.8 mm; C12: 4.0 +/- 0.9 mm; C60: 2.4 +/- 1.0 mm). However, from 12 to 60 months after therapy both groups experienced significant CAL-V loss (P<0.05): two defects in the test group and three in the control group had CAL-V loss >2 mm compared to the 12-month reexamination. Twelve and 60 +/- 3 months after surgery, statistically significant (P<0.05) radiographic bony fill was found in both groups (T12: 1.2 +/- 1.3 mm; T60: 1.5 +/- 2.2 mm; C12: 0.9 +/- 1.4 mm; C60: 1.0 +/- 1.6 mm). Further, 60 months after surgery significant (P<0.05) PBL-V gain was found in both groups (test: 1.8 +/- 2.3 mm; control: 2.2 +/- 1.8 mm). The study failed to show statistically significant differences between test and control regarding CAL-V and PBL-V gain 60 months after surgery.

CONCLUSION

CAL-V gain achieved after GTR therapy in infrabony defects using both bioabsorbable barriers was stable after 5 years in 21 of 26 defects (81%).

Radiographic Parameters for Prognosis of Periodontal Healing of Infrabony Defects: Two Different Definitions of Defect Depth

BACKGROUND

The aim of the present study was to evaluate defect width and two different definitions of defect depth as prognostic factors of periodontal healing in infrabony defects treated by regenerative therapy 6 and 24 months after surgery.

METHODS

In 32 patients with moderate to advanced periodontitis, 50 infrabony defects were treated by the guided tissue regeneration (GTR) technique using non-resorbable or bioabsorbable barriers. Clinical parameters were assessed, and 50 triplets of standardized radiographs were taken before surgery and 6 and 24 months after surgery. Using a computer-assisted analysis, the distances cemento-enamel junction (CEJ) to alveolar crest (AC), CEJ to bony defect (BD), horizontal projection of the most coronal extension of the bony wall to the root surface to BD, width, and angle of the bony defects were measured. Depth of the bony defect was 1) calculated as CEJ-BD minus CEJ-AC (INFRA1) and 2) measured as horizontal projection of the most coronal extension of the bony wall to the root surface to BD (INFRA2).

RESULTS

Whereas statistically significant vertical clinical attachment level gains (CAL-V: 3.36 +/- 1.59 mm/ 3.41 +/- 1.72 mm; P < 0.001) could be found both 6 and 24 months after surgery, bony fill (0.70 +/- 2.52 mm; P = 0.056/1.21 +/- 2.55 mm; P < 0.005) was significant 24 months post-surgically only. In a multilevel regression analysis, CAL-V gain was predicted by bioabsorbable membrane (P = 0.005), baseline probing depths (PD) (P < 0.001), and actual smoking (P < 0.05). Bony fill could be predicted by baseline depth of the infrabony component as determined by INFRA2 (P < 0.05), angulation of bony defect (P < 0.005), and gingival index at baseline (P < 0.001). In narrow (< 37 degrees) and deep (> or = 4 mm) infrabony defects, bony fill was more pronounced than in wide and shallow defects (P < 0.001).

CONCLUSIONS

Improvement achieved by GTR in infrabony defects can be maintained up to 24 months after surgery. Narrow and deep infrabony defects respond radiographically and are to some extent clinically more favorable to GTR therapy than are wide and shallow defects. The infrabony component of bony defects, as determined by the distance from the most coronal extension of the lateral bony wall to BD (INFRA2), is a better predictor of bony fill than that determined by AC-BD (INFRA1).

Comparison of Porous and Non-Porous Teflon Membranes Plus a Xenograft in the Treatment of Vertical Osseous Defects: A Clinical Reentry Study

BACKGROUND

The primary aim of this 9-month randomized, controlled, blinded, clinical reentry study was to compare the regenerative effects of a nonporous polytetrafluoroethylene (NP) periodontal membrane to a porous expanded polytetrafluoroethylene (P) periodontal membrane in the treatment of vertical osseous defects.

METHODS

Twenty-four patients, 11 males and 13 females, age 24 to 74 (mean 50.5 +/- 13.1) provided one site with an intraosseous defect > or = 4 mm and were divided equally and randomly into two groups. Following debridement both groups were grafted with a bovine-derived xenograft coated with a synthetic cell-binding peptide; then the test group received an NP membrane and the control group received a P membrane. All defects were reentered after 9 months. Measurements were performed by a masked examiner.

RESULTS

There were no statistically significant differences (P>0.05) between NP and P groups for any open or closed probing measurement at any time. Similar open initial defect depth for the NP group and P groups (4.8 versus 5.0 mm) demonstrated identical 9-month defect fill of 2.8 mm (57%) for both groups. A difference in crestal resorption for the NP compared to the P group (0.4 versus 0.8 mm) accounted for the difference in mean percent defect resolution, which was 67% for NP compared to 72% for the P group. Overall, nine (75%) of the NP group defects and eight (67%) of the P group defects showed more than 50% defect fill.

CONCLUSION

Treatment of vertical osseous defects with nonporous or porous polytetrafluoroethylene membranes in combination with a xenograft resulted in statistically significant improvement in open and closed probing measurements, with no significant difference between treatment groups.

Two decades of computerized information technologies in dental radiography

The author describes her experiences in developing a radiology department utilizing digital radiography in dentistry.

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.

Clinical and radiographic evaluation of periodontal intrabony defects treated with guided tissue regeneration. A pilot study

BACKGROUND

The aim of this clinical and radiographic study was to evaluate the effect of guided tissue regeneration using a bioabsorbable barrier in the treatment of intrabony defects in humans.

METHODS

Intrabony osseous defects (2 or 3 walls) around mandibular canines and premolars were treated in 10 systemically healthy patients with ages ranging from 35 to 56 years. Prior to the surgical phase, patients were enrolled in a strict maintenance program including oral hygiene instructions and scaling and root planing (presurgical Pi and GI < 10%). Patients were seen for professional prophylaxis during the duration of the study. Clinical measurements were performed with an electronic probe at baseline and at reentry 8 months following surgical therapy. Measurements included clinical attachment levels (CAL), gingival margin levels (GML), probing depths (PD), bone defect levels (BDL), and alveolar crest level (ACL). A split mouth design was used. Quadrants were randomly assigned for treatment by GTR (experimental) or open flap debridement alone (control). Standardized radiographs were taken at baseline and at reentry. Digital images were analyzed by subtraction to assess changes in area (A) and optical density (OD). Data were evaluated using paired t test.

RESULTS

Statistically significant differences were found in both groups when comparing baseline and post-treatment values for CAL, GML, PD, and BDL (P < 0.0 1). Greater reductions in BDL and gain in A and OD were observed in the GTR group when compared to control (P < 0.01). Both therapies were effective in improving the clinical parameters assessed.

CONCLUSION

Clinical and radiographic findings from this study demonstrated more bone fill in sites treated with GTR.

Comparison of conventional and TACT (Tuned Aperture Computed Tomography) digital subtraction radiography in detection of pericrestal bone-gain

Tuned Aperture Computed Tomography or TACT is a relatively new technique that transforms correlated two-dimensional images into a three-dimensional display. Associating TACT with digital subtraction radiography (TACT-DSR) may enhance its use in the detection of diseases. This study aims to assess observer performance in the task of detecting simulated bone-gain in periodontal defects, comparing conventional and TACT DSR. Buccal, lingual and proximal pericrestal bony defects in a human dry skull were imaged with and without increments of crushed-bone and wax mixtures using standardized vertical bitewing projections, acquired with an intraoral digital receptor in a tomographic X-ray machine. One hundred and twenty pairs of baseline and follow-up images were obtained for each imaging modality. Post-acquisition processing including image-registration, density-correction and subtraction operation were applied to both transmission images and TACT-slices. Eight calibrated observers evaluated the presence or absence of pericrestal bone-gain using a 5-point confidence scale. Details about the location of periodontal defects and the amount of bone-gain for each subtracted image were recorded and used in the statistical analysis. Observer performance and study design factors were analyzed by means of receiver operating characteristic (ROC) curve analysis and ANOVA. Mean values of areas under ROC curves for bone-gain detection performance were 0.82 for conventional DSR and 0.90 for TACT-DSR. TACT-DSR provided statistically superior detection performance of simulated periodontal bone-gain over conventional DSR for tooth-obscured defects (p = 0.001) and for the smallest bone mass (p = 0.024). The findings support TACT-DSR's potential to provide greater sensitivity and technique flexibility in detecting periodontal bone-gain than standard DSR.

A composite polymer/tricalcium phosphate membrane for guided bone regeneration in maxillofacial surgery

The aim of the study was the development of a resorbable membrane for guided bone regeneration (GBR) with improved biocompatibility, which should be stiff enough to avoid membrane collapse during bone healing. Combining a bioactive ceramic with a resorbable polymer may improve the biocompatibility and osteoconductivity of resorbable devices. The present article describes the preparation, the mechanical properties, and the in vitro degradation characteristic of a composite membrane made of poly(L, DL-lactide) and alpha-tricalcium phosphate in comparison to a membrane made of pure poly(L, DL-lactide). The tensile strength and the elastic modulus as well as the molecular weight of the membranes were measured after in vitro degradation in buffer at 37 degrees C up to 28 weeks. The initial tensile strength of the composite and the polymer membrane was 37.3 +/- 2.4 MPa and 27.7 +/- 2.3 MPa and the elastic modulus 3106 +/- 108 MPa and 3101 +/- 104 MPa, respectively. The mechanical properties remained constant up to 8 weeks and then decreased slowly until week 28. The molecular weight of both membranes decreased steadily from 170,000 D to 30,000 D. It was concluded that the mechanical requirements for a membrane for GBR were fulfilled by the composite membrane.

Radiographic defect depth and width for prognosis and description of periodontal healing of infrabony defects

BACKGROUND

The aims of the present study were to evaluate 1) defect depth and width as a prognostic factor and 2) change in defect width as a describing parameter of periodontal healing in infrabony defects treated by regenerative therapy after 6 and 24 months.

METHODS

In 24 patients with advanced periodontitis, 39 infrabony defects were treated by guided tissue regeneration (GTR) using expanded polytetrafluoroethylene (ePTFE) (n = 7) or bioabsorbable barriers (n = 32). Clinical parameters were assessed and 39 standardized radiographs (in triplicate) were taken before and 6 and 24 months after surgery. Using a computer-assisted analysis, the depth, width, and angle of the bony defects were measured.

RESULTS

Statistically significant vertical clinical attachment gains (CAL-V: 3.15 +/- 1.63 mm to 3.31 +/- 1.65 mm; P<0.001) and bony fill (1.30 +/- 2.53 mm; P<0.01 to 1.54 +/- 2.70 mm; P<0.005) were observed 6 and 24 months postsurgically. In a multilevel regression analysis CAL-V gain was predicted by baseline CAL-V (P <0.0001), actual smoking (P <0.05), and age (P <0.1). Bony fill could be predicted by baseline height of the infrabony component (P<0.0001), gingival index at baseline (P<0.05), and actual smoking (P <0.01). In narrow (<26 degrees) and deep (> or = 3 mm) infrabony defects bony fill was more pronounced than in wide and shallow defects (P <0.05).

CONCLUSIONS

Improvement achieved by guided tissue regeneration in infrabony defects can be maintained up to 24 months after surgery. Narrow and deep infrabony defects respond radiographically and to some extent clinically more favorably to GTR therapy than wide and shallow defects. However, depth of the infrabony component was a stronger prognostic parameter than defect angle. Actual smoking impairs the results of GTR therapy in infrabony defects.

The effect of membrane exposure on the outcome of regenerative procedures in humans: a meta-analysis

BACKGROUND

The significance of early membrane exposure on the regenerative outcome in guided tissue regeneration (GTR) and guided bone regeneration (GBR) procedures is somewhat controversial. Several clinical trials have shown better response when the membranes remained submerged (S) compared to those that have become exposed (E) during healing. Other studies have failed to show any such difference. Small sample size and/or large standard deviation of the changes might account for these discrepancies. The purpose of this meta-analysis is to critically combine the existing data in order to provide meaningful information based on a large database.

METHODS

Studies of GTR in Class II furcation and intrabony defects (IBD), together with GBR around dental implants, where the membrane became exposed during the postoperative period, were combined to form 3 separate databases. A meta-analysis was employed to compare the 2 subgroups (E versus S) in each of the databases. First, weighted mean changes and weighted standard errors were calculated for each subgroup. Next, an individual study P value was calculated (1-tailed Student t test); finally, a combined Fisher's P statistic (with 5% significance level) was calculated from the individual P values.

RESULTS

Five studies with a total of 101 sites were included in the furcation database; 43 of these sites became exposed. Mean horizontal attachment level (AL) gain for the S sites (3.72 +/- 0.15 mm) was slightly greater than that of the E sites (3.06 +/- 0.15 mm; P = 0.030257). For the intrabony group, there were 309 sites in 5 studies: of these, 142 sites became exposed. Mean gain in vertical AL was 4.22 +/- 0.15 mm and 4.69 +/- 0.13 mm for the E and S group, respectively (P = 0.011415). The GBR group included 60 sites in 2 studies: new bone formation in the 24 S sites (3.01 +/- 0.38 mm) was 6-fold greater compared with the 36 E sites (0.56 +/- 0.45 mm). These differences were also statistically significant (P = 0.001875).

CONCLUSIONS

Membrane exposure during healing had a major negative effect on GBR around dental implants but only a minimal effect on GTR around natural teeth.

Enamel matrix derivative in the treatment of human intrabony osseous defects

BACKGROUND

There is limited information available from clinical trials regarding the performance of enamel matrix derivative (EMD) in the treatment of periodontal intrabony defects. This randomized, double-blind, placebo-controlled, split-mouth study was designed to compare the clinical and radiographical effects of EMD treatment to that of placebo-controlled treatment for intrabony defects.

METHODS

Sixteen patients were included, each of whom had 1 or 2 pairs of intrabony defects located contralaterally in the same arch. Thirty-six intrabony defects were randomly assigned treatment with flap surgery plus EMD or flap surgery plus placebo. At baseline and at the 12-month follow-up evaluation visit, clinical and radiographic measurements were determined. Data were statistically analyzed using the Wilcoxon-signed rank test (alpha = 0.05).

RESULTS

At the 12-month visit, bleeding on probing for the EMD group was 0.11 +/- 0.32 compared to the placebo group, 0.61 +/- 0.50 (P <0.05). Probing depth reduction was greater in the EMD group (3.00 +/- 0.97 mm) compared to the placebo group (2.22 +/- 0.81 mm) (P <0.05). Mean values for clinical attachment gain in the EMD and the placebo groups were 1.72 +/- 1.07 mm and 0.83 +/- 0.86 mm, respectively (P <0.05). Vertical relative attachment gain was 38.5 +/- 22.6% in the EMD group and 21.4 +/- 25.2% in the placebo group (P<0.05). Radiographic bone density gain was greater in the EMD (20.2 +/- 16.6%) compared to the placebo group (-3.94 +/- 23.3%) (P<0.01).

CONCLUSIONS

Treatment with flap surgery and EMD, compared to flap surgery with placebo, produced a significantly more favorable clinical improvement in intrabony periodontal defects.

New clinical materials and techniques in guided tissue regeneration

AIM

To review the evidence on using Guided Tissue Regeneration (GTR) techniques and materials in various clinical circumstances.

METHOD

Literature review.

MAIN OUTCOME MEASURES

The success of GTR techniques and materials in halting or reversing the destruction of tooth attachment apparatus caused by progressive periodontal disease.

RESULTS

GTR and osseous grafting are the two techniques with the most clinical and histological documentation of periodontal regeneration.

CONCLUSIONS

GTR materials, whether non-resorbable or bioabsorbable, give similar clinical results. GTR procedures have been demonstrated to be clinically effective in treating infrabony osseous defects, recession defects, preserving alveolar bone in recent extraction sites and in some types of furcation defects. GTR procedures are technique sensitive and are adversely affected by poor home oral hygiene care, poor follow-up professional maintenance care and smoking.

Guided tissue regeneration with bioabsorbable barriers: intrabony defects and class II furcations

BACKGROUND

The aim of this study was to compare the effects of guided tissue regeneration (GTR) using 2 different bioabsorbable barriers (control: polylactide acetyltributyl citrate; test: polydioxanon). The polydioxanon barrier is an experimental membrane for GTR therapy that consists of a continuous occlusive barrier that has a layer of slings on the side that is meant to face the mucoperiosteal flap.

METHODS

In 21 patients with 22 pairs of similar contralateral defects (30 intrabony and 14 Class II furcation lesions), each defect was randomly assigned for treatment with either control (c) or test (t) devices. At baseline and 12 months after surgery, clinical measurements, plaque index (PI) gingival index (GI), probing depth (PD), and vertical and horizontal clinical attachment loss (CAL-V; CAL-H) and standardized radiographs were obtained.

RESULTS

Barrier exposure was commonly observed in both groups. Four weeks after surgery 61% of all barriers were exposed to some extent. However, both treatments revealed a significant GI reduction (P <0.005), PD reduction (-3.08 +/- 2.29 mm [t]; -3.52 +/- 2.67 mm [c]; P <0.001) and CAL-V gain (2.44 +/- 2.29 mm [t], 2.80 mm +/- 2.21 [c]; P <0.001) 12 months after surgery in all defects. Within the intrabony defects significant bony fill (2.03 +/- 1.70 mm [t]; 1.91 +/- 1.20 mm [c]; P = 0.001), and within the furcations a significant but small CAL-H gain (0.79 +/- 0.68 mm [t]; 1.13 +/- 1.44 mm [c]; P <0.05), was observed.

CONCLUSIONS

Regarding GI and PD reduction as well as CAL-V and CAL-H gain, this study failed to reveal statistically significant or clinically relevant differences between test and control 12 months postsurgically. Thus, the use of both bioabsorbable barriers in GTR therapy may be recommended.

Evidence for healing of Class II and Class III furcations 24 months after guided tissue regeneration therapy: digital subtraction and clinical measurements

BACKGROUND

The aim of this study was to compare bone regeneration as assessed by subtraction radiography with clinical attachment measurements 24 months after regenerative surgery.

METHODS

In 24 patients with advanced periodontitis, 34 Class II and 10 Class III furcations were treated by guided tissue regeneration using expanded polytetrafluoroethylene (n = 18) or bioabsorbable barriers (n = 26). Clinical parameters were assessed and 40 pairs of standardized radiographs were taken before and 24 months after surgery. Bony gain within furcations was assessed using subtraction analysis.

RESULTS

In Class II furcations, statistically significant (P <0.001) vertical (CAL-V: 1.06+/-1.56 mm) and horizontal (CAL-H: 2.05+/-1.24 mm) attachment gain was observed 24 months postsurgically. Within Class III defects CAL-V gain was assessed 1.78+/-1.43 mm (P <0.005). CAL-H gain in buccal and lingual Class II furcations was explained by the relative density gain, baseline CAL-H, gingival index (GI) reduction, and individual patients (P <0.001) whereas, multiple regression analysis failed to show a relation between CAL-H gain and any of the subtraction parameters for interproximal furcations. Vertical attachment gain in interproximal sites was explained by net bony area gain (subtraction), PD and GI reduction, baseline CAL-V, defect type, smoking, and individual patients (P<0.001).

CONCLUSIONS

There was a statistically significant correlation between clinical and radiographic improvements within furcation defects. However, this correlation was modulated by other factors such as baseline CAL-V or CAL-H, PD and GI reduction, or smoking. The relative density gain seemed to sufficiently describe bony changes related to clinical changes within buccal and lingual furcations, whereas bone area gain suitably described bony changes in interproximal Class II and III furcations.

Quantitative digital subtraction radiography for the determination of small changes in bone thickness: an in vitro study

OBJECTIVE

The objective of this study was to determine the ability of quantitative digital subtraction radiography to detect small changes in bone thickness adjacent to tooth roots.

STUDY DESIGN

A series of cortical or cancellous bone slices with a 50 microm-stepwise increasing thickness were attached to 4 porcine mandible sections covering buccal and interproximal "defect" regions. Standardized radiographs were quantitatively evaluated for radiographic density changes with the use of digital subtraction radiography. Furthermore, all radiographs were conventionally evaluated by 10 clinicians. The Wilcoxon signed-rank test and the Mann-Whitney U test were used for statistical analysis (alpha = 0.05).

RESULTS

A high linear correlation was found between the actual thickness of bone slices and radiographic density changes (cortical bone: r2 = 0.89 to 0.99; cancellous bone r2 = 0.61 to 0.86, p < or = 0.001). A certain increase in bone thickness caused a 3 times higher increase in radiographic density for cortical bone than for cancellous bone (p < or = 0.05). The detection limits of digital subtraction radiography were 200 microm for cortical and 500 microm for cancellous bone, whereas the detection limits of conventional radiography were 600 microm and 2850 microm, respectively.

CONCLUSIONS

This in vitro study demonstrated a very high correlation between the objective, quantitative assessment of subtle changes in alveolar bone by digital subtraction radiography and the true changes in bone thickness.