In vitro evaluation of the human gingival fibroblast/gingival mesenchymal stem cell dynamics through perforated guided tissue membranes: cell migration, proliferation and membrane stiffness assay.

BACKGROUND: Migration of gingival fibroblasts/gingival mesenchymal stem cells through macro-perforated barrier membranes may allow them to participate positively in periodontal regeneration. The optimal guided tissue membrane perforation diameter that could favor maximum cell migration into the defect area and at the same time act as an occlusive barrier for gingival epithelium and its associated gingival extracellular matrix component is not yet identified. MATERIAL AND METHODS: Cultured human gingival fibroblasts/gingival mesenchymal stem cells were placed in the upper chambers of 12-well collagen-coated polytetrafluoroethylene transwells, which were manually perforated with 0.2, 0.4 and 0.7 mm sized pores. The lower chambers of the transwells received blood clot as an attraction medium. The number of cells that have migrated to the lower chambers was calculated. Proliferation of these cells was evaluated using MTT assay. Scanning electron microscopy images were obtained for the lower surfaces of the transwell membranes. Perforated bovine collagen membranes (Tutopatch® ) were subjected to mechanical testing to determine the tensile strength and modulus of elasticity. RESULTS: Group 3 (0.7 mm) showed significantly higher values for cell migration and proliferation. All groups showed a small degree of extracellular matrix migration through membrane perforations. Scanning electron microscopy evaluation revealed variable numbers of cells in fibrin matrices located mainly around the pore edges. There were non-significant differences between groups regarding mechanical properties. CONCLUSIONS: The present study demonstrated that macro-membrane perforations of 0.2, 0.4 and 0.7 mm are suitable pore diameters that could maintain membrane stiffness and allow for cellular migration. However, these membrane perforation diameters did not allow for total gingival connective tissue isolation.

Gingival crevicular fluid vascular endothelial cell growth factor and platelet-derived growth factor-BB release profile following the use of perforated barrier membranes during treatment of intrabony defects: a randomized clinical trial.

BACKGROUND AND OBJECTIVE: Perforated barrier membranes open channels between the suprabony and intrabony compartments of the defect, which could allow for more physiologic cellular interactions between different components of the periodontium during guided tissue regeneration surgery. To test this assumption, this study was designed to evaluate levels of vascular endothelial cell growth factor (VEGF) and platelet-derived growth factor (PDGF)-BB in gingival crevicular fluid during the early stages of healing of localized intrabony defects treated with perforated membranes (PMs) or non-PMs, as compared with open flap debridement. MATERIAL AND METHODS: Thirty non-smoking patients with severe chronic periodontitis participated in this prospective, randomized and single blinded trial. Each patient contributed one interproximal defect that was randomly assigned to the PM group (n = 10), occlusive membrane (OM) group (n = 10) or open flap debridement (OFD) group (n = 10). Plaque index, gingival index, probing depth, clinical attachment level and the intrabony depth of the defect were measured at baseline and reassessed at 6 and 9 mo after therapy. Gingival crevicular fluid samples were collected on days 1, 3, 7, 14, 21 and 30 d after therapy for the changes in VEGF and PDGF-BB levels. RESULTS: During the early stages of healing (1, 3 and 7 d), the mean VEGF and PDGF-BB concentrations at sites treated with PMs and OFD peaked with a statistically significant difference as compared with the OM-treated group. VEGF and PDGF-BB levels at sites treated with PMs and OFD were not statistically different. Growth factor levels decreased sharply in the samples obtained at days 21 and 30 with non-significant differences between the three groups. Nine months after therapy, the PM-treated group showed a statistically significant improvement in probing depth, clinical attachment level and intrabony defect compared to the OM and OFD groups. CONCLUSIONS: Within the limits of the present study, one can conclude that PM coverage of periodontal defects is associated with initial gingival crevicular fluid growth factor upregulation that could improve the clinical outcomes of guided tissue regeneration surgery.

Effect of locally delivered minocycline microspheres on markers of bone resorption.

BACKGROUND: Gingival crevicular fluid (GCF) biomarkers associated with bone resorption may be useful to determine periodontal disease status and response to therapy. The pyridinoline cross-linked carboxy-terminal telopeptide of type I collagen (ICTP), a bone-specific degradation product, and interleukin 1-beta (IL-1), a potent bone-resorptive cytokine, have both been associated with periodontal disease activity. Minocycline is a tetracycline derivative possessing antimicrobial effects on periodontal pathogens and inhibitory properties on matrix metalloproteinases (MMPs) associated with tissue destruction. The aim of this study was to evaluate the effect of periodontal treatment in the form of scaling and root planing (SRP) and locally administered minocycline microspheres on the GCF levels of ICTP and IL-1. METHODS: Forty-eight chronic periodontitis patients were randomly assigned to 2 groups (SRP plus subgingival application of vehicle control [SRP + V], or SRP plus subgingival application of minocycline microspheres [SRP + M]) and monitored at 8 sites per subject at baseline and 1, 3, and 6 months. Four shallow (PD < or = 3 mm) and 4 deep (PD > or = 5 mm) sites were evaluated for both marker levels and for probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP). Eight periodontally healthy control subjects with no probing depths >3 mm and no loss of attachment were also monitored at the same time intervals. GCF levels of ICTP and IL-1 were determined using radioimmunoassay and enzyme-linked immunosorbent assay techniques, respectively. RESULTS: Significant differences (P<0.001) in GCF levels of ICTP and IL-1 were found between deep and shallow sites at all time points in both treatment groups. In addition, healthy subjects demonstrated significantly reduced levels of both markers compared to both shallow and deep sites in periodontitis patients (P <0.001). Only the SRP + M treated patients exhibited significant reductions (P <0.05) in both ICTP and IL-1 levels 1 month after treatment. Furthermore, the SRP + M group demonstrated significantly lower IL-1 levels (P <0.02) at 1 month compared to the SRP + V group. CONCLUSIONS: Results of this study indicate that GCF levels of ICTP and IL-1 correlate with clinical measures of periodontal disease and may aid in assessing disease status and response to periodontal therapy. Furthermore, local administration of minocycline microspheres led to a potent short-term reduction in GCF IL-1 levels. Additional studies are needed to address whether repeated administration of scaling and root planing along with minocycline microspheres will achieve long-term reductions in GCF ICTP and IL-1 levels.

Effect of non-surgical periodontal therapy on C-telopeptide pyridinoline cross-links (ICTP) and interleukin-1 levels.

BACKGROUND: Biochemical markers harvested from gingival crevicular fluid (GCF) may be useful to identify and predict periodontal disease progression and to monitor the response to treatment. C-telopeptide pyridinoline cross-links (ICTP), a host-derived breakdown product specific for bone, and interleukin-1beta (IL-1), a potent bone-resorptive cytokine, have been associated with periodontal tissue destruction. The aim of this study was to examine the effect of non-surgical periodontal therapy on GCF levels of ICTP and IL-1. METHODS: Twenty-five chronic periodontitis subjects were monitored at 8 sites per subject at baseline prior to scaling and root planing and 1, 3, and 6 months after therapy. Four shallow (probing depths < 4 mm) and 4 deep (probing depths > or = 5 mm) sites were monitored for both marker levels and clinical parameters. GCF was collected for 30 seconds on paper strips, and levels of ICTP and IL-1 were determined using radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) techniques, respectively. Clinical measurements included probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP). RESULTS: Deep sites exhibited significantly (P<0.001) higher ICTP and IL-1 levels compared to shallow sites at all time intervals. ICTP demonstrated a stronger association to clinical parameters than IL-1 including a modest correlation (r = 0.40, P<0.001) between ICTP and attachment loss. Significant improvements in PD, CAL, and BOP were observed at 1, 3, and 6 months in all sites (P<0.01). However, non-surgical mechanical therapy did not significantly reduce ICTP and IL-1 levels over the 6-month period. Further examination of subjects based on smoking status revealed that ICTP levels were significantly reduced at 3 and 6 months and IL-1 levels reduced at 3 months among non-smokers only. CONCLUSIONS: A single episode of non-surgical mechanical therapy did not significantly reduce biochemical markers associated with bone resorption in patients exhibiting chronic periodontitis. Future longitudinal studies are warranted to specifically evaluate the relationship between C-telopeptide pyridinoline cross-links and periodontal disease progression.

Exostosis following a subepithelial connective tissue graft.

This case report describes the formation of an unusual unaesthetic gingival enlargement during a five year post operative period subsequent to a subepithelial connective tissue graft placed facial to teeth #4 and #6. Histological assessment of the enlarged tissue indicated that it consisted of viable bone and marrow. The exostosis was reduced with rotary instruments and acceptable soft tissue aesthetics were created using a carbon dioxide laser for gingivoplasty. Possible causes for this unusual enlargement are discussed.

Dental implants in periodontal therapy.

Over the past 30 years, research has validated the success of osseointegrated implants as a viable alternative to fixed or removable prosthetic restorations. Periodontists are extensively trained in surgical procedures to treat and maintain patients with edentulous and partially edentulous arches. They also have a primary role in treatment planning and maintenance therapy. Thus, periodontists routinely integrate endosseous implants into periodontal therapy. This paper was prepared by the Research, Science and Therapy Committee of the American Academy of Periodontology and is intended to inform the dental profession regarding the utility of endosseous dental implants in the treatment of full and partial edentulism.

Longitudinal study of dental implants in a periodontally compromised population.

BACKGROUND: The purpose of this longitudinal study was to determine the clinical status and the composition of the subgingival microbiota of dental implants and natural teeth in patients with a history of periodontitis. METHODS: Twenty-five partially edentulous patients treated for moderate to advanced adult periodontitis and having a total of 42 implants participated in this 3-year study. The assessment of clinical status was done 1, 2, and 3 years after prosthetic loading (T1, T2, and T3, respectively). Clinical parameters evaluated included probing depth (PD), clinical attachment level (CAL), gingival index (GI), and plaque index (PI). The subgingival microbiota at peri-implant and periodontal sites were analyzed at T1 and T2. RESULTS: No significant difference in clinical parameters between implants and teeth and within the 2 groups between different time points was observed through the study. PD and CAL measurements of sampled periodontal and peri-implant sites did not show any statistically significant difference through the study and between the 2 groups. PI of sampled periodontal sites showed a statistically significant improvement during the study. From the morphological observation of the subgingival microbiota, a significant difference in the composition of motile rods between implants and teeth was found at T1. There were no differences detected in the subgingival microbiota, culturally identified at peri-implant and periodontal sites for the duration of the study. CONCLUSIONS: In conclusion, implants were colonized by the indigenous periodontal microbiota and were well maintained in patients with a history of periodontitis. No significant association between progressing or non-progressing periodontal or peri-implant sampled sites in terms of loss of attachment and infection with at least one of the searched periodontal pathogens was found, suggesting that the presence of putative periodontopathogens at peri-implant and periodontal sites may not be associated with future attachment loss or implant failure.

Current periodontal plastic procedures around teeth and dental implants.

Periodontal plastic procedures are performed to prevent or correct anatomical, developmental, traumatic or plaque-induced defects of the gingiva, alveolar mucosa or bone. The majority of these procedures are performed in combination with restorative and/or orthodontic therapy, with the primary goal of enhancing esthetics. In this review, some of the more prominent techniques currently available to address mucogingival deficiencies, including pedicle grafts, free soft tissue grafts and combination grafts, are illustrated. In addition, potential complications associated with periodontal plastic procedures will be discussed.

Periodontal cosmetic surgery.

Periodontal plastic procedures are performed to prevent or correct anatomical, developmental, traumatic, or plaque induced defects of the gingiva, alveolar mucosa, or bone. The majority of these procedures are performed in combination with restorative and/or orthodontic therapy with the primary goal of enhancing aesthetics. In this review some of the more prominent techniques currently available to address mucogingival deficiencies including pedicle grafts, free soft tissue grafts, and combination grafts are illustrated. In addition, potential complications associated with periodontal plastic procedures are discussed.

Variability of hydroxyapatite-coated dental implants.

Uniformity, surface roughness, and chemical phase structure are all important features of implant coatings. While the first two variables are important for implant placement, the phase structure affects implant fixation. This study examined the coating morphology and the amount, size, and distribution of crystalline regions of press-fit and screw-type dental implants. Implants obtained from five commercial vendors were sectioned sagittally, mounted, and polished to reveal the coating microstructure. The crystalline phase content varied depending on the implant supplier; however, general trends were observed. Amorphous regions were predominantly found at the metal interface and decreased toward the outside of the coating, producing a crystallinity graded coating. The distal end of the implant, where heat build-up was more likely during the coating procedure, displayed a higher crystalline content and larger crystalline regions. Similarly, the thread apex consisted of more of a crystalline phase. The results of this study of coating microstructure may be used to improve the quality and performance of implants and may help to explain different in vivo responses to the many available varieties of hydroxyapatite-coated dental implants.

Modern supragingival plaque control.

Supragingival plaque control is essential for the maintenance of oral health. Despite the many chemotherapeutic agents available as mouthrinses and toothpastes, mechanical plaque removal is still the best method to achieve effective plaque control. This is due, in part, to the lack of development of oral antimicrobials with the effectiveness and substantivity of chlorhexidine gluconate but without its adverse effects of dental staining and calculus formation. The use of the numerous mechanical (manual and electric) oral hygiene devices extant and their effectiveness, however, are dependent upon patient dexterity and compliance and concomitant active professional treatment for the monitoring of home care, oral hygiene instruction and patient motivation. This paper evaluates the current methods available to reduce plaque and gingivitis with emphasis on their effectiveness at both supragingival plaque control and disease prevention. In addition, recent studies on the newer oscillating/rotating electric plaque removers and interdental cleaning devices will be discussed as related to their efficacy and compliance.

Report of the Sinus Consensus Conference of 1996.

Retrospective data from sinus floor augmentation bone grafts were collected from 38 surgeons for 1007 sinus grafts that involved the placement of 2997 implants over a 10-year period, with the majority of the implants followed for 3 years or more postrestoration. There were 229 implant failures reported. Various root-form implants and grafting modalities were used. A consensus conference was organized to evaluate the data and reach a consensus on optimal treatment protocols. The complete database demonstrated a 90.0% success rate for implants placed in sinus grafts with at least 3 years of function. Differences in grafting materials, implant surfaces, and timing protocols were statistically analyzed. However, the database was so multivariate and multifactorial that it was difficult to draw definitive conclusions; these must await controlled prospective studies. The consensus conference therefore developed and voted on multiple consensus statements derived by committee review for bone graft materials, type of implants, timing for implant placement, failure analysis, radiographic analysis, indications/contraindications, prosthetics, and nomenclature. Several consensus statements were obtained, the most significant being that the sinus graft should now be considered a highly predictable and effective therapeutic modality.

Periodontal status and subgingival microbiota of insulin-dependent juvenile diabetics: a 3-year longitudinal study.

This study examined for 3 years the changes in periodontal status and the possible correlations with selected subgingival microbiota and diabetic conditions in a group of 16 insulin-dependent diabetes mellitus (IDDM, JD) patients as compared with their 16 healthy cohabiting siblings (HS). JD patients were monitored every 3 months for levels of glycosylated hemoglobin (HbA1C). Clinical and microbiological parameters were measured 6 weeks before drawing blood to determine levels of HbA1C. Periodontal parameters were measured at baseline (TO), year 2 (T2), year 3 (T3) and included: probing depth (PD), attachment level (AL), sulcus bleeding index (SBI), and plaque index (PI). Two sites in each patient were selected for microbial samples: a mesio-facial aspect of the maxillary right first molar (defined as constant site, CS) and a site with the greatest probing depth (defined as deepest site, DS). Microbial samples were analyzed by culture techniques. No significant differences in clinical parameters were found between diabetics and healthy siblings at any examination. The SBI in the non-diabetic group at T2 and at T3 was significantly lower than at baseline. PD and AL of constant sites in the diabetic group at T3 were significantly higher than baseline. There was a significant increase in Prevotella intermedia at T3 as compared with baseline for deepest sites in the diabetic group. Cluster analysis revealed, in a former study, two clusters (IV and V) at baseline which were significantly different from the overall mean regarding composition of Porphyromonas gingivalis and Capnocytophaga spp. They were not significantly different for periodontal parameters from TO to T3. These data would suggest no significant differences in clinical parameters between the diabetics and non-diabetic siblings throughout this 3-year longitudinal study.

In vitro changes of hydroxyapatite coatings.

The stability and degradability of hydroxyapatite coatings on dental implants depends on the dissolution of the individual chemical phases. Hydroxyapatite-coated dental implants exhibit a range of amorphous-phase content. Two tests were conducted to observe the course of coating degradation. The first test showed degradation of both crystalline and amorphous coatings by cracking and dissolution after immersion in Ringer's solution. Concomitant saturation of the implants in the solution modified the coated surface with precipitated crystalline apatite. A second test, intended to replicate the conditions of infection by decreasing pH, illustrated preferred dissolution of the amorphous phase, liberating crystalline segments. It is expected that morphologic changes could influence the rate of bone bonding and therefore could alter or control implant-tissue interactions.

The cytokines: a review of interleukins.

Over the past decade much has been elucidated concerning the cellular and molecular basis for health and disease. This increase in information has created a large gap in knowledge between the research scientist and the clinician. The following review attempts to bridge this gap by describing each of the thirteen interleukins and relating their functions to the clinical presentation of periodontal disease.

Osteoporosis: a risk factor for dental implants and in the prognosis of periodontal therapy.

Two patients were referred to the Graduate Periodontal Clinic, one for placement of dental implants, the other for treatment of advanced periodontal disease. It was determined from an analysis of the Hounsfield scales of bone density from a CT scan that the patient requesting dental implants had severe osteoporotic changes and was, therefore, not a good candidate for the procedure. The second patient's medical history revealed multiple fractures occurring over the years that suggested the presence of osteoporosis. This diagnosis was subsequently confirmed by referral of the patient to an osteoporosis clinic.

Periodontal status and selected cultivable anaerobic microflora of insulin-dependent juvenile diabetics.

The periodontal status and subgingival microflora of insulin-dependent juvenile diabetic (JD) patients (n = 16, mean age = 11.3) were compared with that of their non-diabetic cohabiting healthy siblings (HS, n = 16, mean age = 13.2). JD patients were monitored every 3 months for levels of glycosylated hemoglobin (HbA1c) and clinical and microbial parameters were measured 6 weeks before drawing blood for levels of HbA1c (M% = 8.76). Clinical indices, measured for the entire permanent dentition, included: probing depth (PD), attachment level (AL), sulcus bleeding index (SBI), and plaque index (PI). Subgingival plaque samples were obtained at 2 sites from each subject; whenever possible, the site with the deepest probing depth and the mesial aspect of the maxillary right first molar were used. Microbial analyses were determined by cultural characteristics and biochemical tests. No significant differences were detected in any of the clinical indices for the entire dentition. The mean AL for JD sites was 2.32 +/- 0.83 mm and for HS sites was 2.2 +/- 0.85 mm. Mean percentage of total cultivable anaerobic microflora included Capnocytophaga spp. (JD, 13.21%; HS, 11%) and Porphyromonas gingivalis (JD, 5.1%; HS, 7.9%). Differences between the two groups were not statistically significant. When cluster analysis was performed on sampled sites, one cluster group in JD patients showed significantly elevated P. gingivalis and lower Capnocytophaga spp. levels as compared to the overall mean. The clinical parameters of this cluster were characterized by statistically significant greater loss of attachment and probing depth. These data would suggest few differences between JD patients and their HS in this population.