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.

Lysozyme-mediated de-chaining of Streptococcus mutans and its antibacterial significance in an acidic environment.

The ability of physiological amounts of lysozyme to de-chain two serotype c strains of Streptococcus mutans was determined. Both human and hen lysozymes were equally effective in chain breakage of S. mutans DPR and S. mutans DJR. De-chaining did not affect growth of cultures, but resulted in finely dispersed suspensions, at stationary phase, which were visibly different from untreated cultures. Less than 50 micrograms lysozyme per ml culture medium reduced chain length to virtually all diplococci and single cells, and this chain disruption increased total viable cell count. De-chaining required an active enzyme indicating that a degree of hydrolysis of the peptidoglycan occurred at the septae of the streptococci. De-chained S. mutans did not survive as well as streptococci of normal chain length when incubated under acidic conditions (pH 5.5), but gross cellular lysis was not apparent. The reduced aciduric property of the disrupted chains may have been due to a participation of autolysins or to a lethal triggered by the lysozyme-damaged peptidoglycan. De-chaining may be a mechanism by which lysozyme could regulate the levels of S. mutans in acidogenic plaque samples.

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.

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.

In vivo assay of crevicular leukocyte migration. Its development and potential applications.

Defects in neutrophil or polymorphonuclear leukocyte (PMNL) chemotaxis have been observed in a number of clinical conditions, including Down's syndrome and insulin-dependent diabetes mellitus (IDDM), which tend to be associated with severe forms of periodontal disease. In addition, impaired PMNL chemotaxis is frequently detected in individuals with localized juvenile periodontitis (LJP). The ability to monitor PMNL function in vivo at the gingival sulcus should therefore be useful as a diagnostic test. In this regard, we developed a technique which measures the response of PMNLs to a chemotactic agent, e.g., casein and N-formylmethionylleucylphenylalanine (N-FMLP) placed directly into gingival crevices. The development of the technique and its relationship to in vitro assays of chemotaxis are discussed, and data obtained from tests of the assay on control and streptozotocin-induced diabetic rats and human subjects with various periodontal diseases and IDDM are presented. As compared with healthy subjects and control animals, atypical (double peak) and reduced crevicular PMNL response patterns were observed during oral and systemic diseases. This suggests that the in vivo assay with appropriate modifications can be used diagnostically to assess PMNL migratory dysfunction and to identify individuals who may be susceptible to severe forms of periodontal disease.

In vivo crevicular leucocyte response in humans to a chemotactic challenge. Effects of periodontal diseases.

An in vivo assay was recently developed to monitor the crevicular leucocyte response to chemotactic agents, e.g., casein and N-formyl peptides. This method was used to monitor humans with little or no gingival disease (C group), gingivitis (G group), chronic periodontitis (CP group) and localized juvenile periodontitis (LJP group). Casein (0.2 microliters, 2 mg/ml) was placed into an isolated gingival crevice of each subject with a calibrated wire loop and the time recorded (t = 0). Leucocytes were counted in crevicular washes (10 microliters) 15 minutes later and every 5 minutes thereafter up to t = 50 minutes. This protocol was repeated for the crevice of an adjacent tooth except that the crevicular fluid flow response to the chemotactic challenge was monitored. The C, G and CP subjects showed a similar pattern of response to the chemoattractant with a single "peak" of leucocytes at approximately t = 25 minutes. However, the peak cell count was much greater in the G and CP groups than in the C group. LJPs showed an abnormal pattern with two leucocyte peaks, one at approximately 25 minutes and the other at 45 minutes. Both peaks tended to be higher than the single peak seen in Cs but were significantly lower than that in Gs or CPs, even at similar levels of inflammation. In addition, the peak leucocyte response (to casein) in LJPs did not increase with increasing leucocyte counts in the unchallenged (resting) crevice, whereas a positive relationship was seen in the other groups of subjects. These data suggest that this new assay may provide important diagnostic information on in vivo neutrophil migration in the gingival crevice and on susceptibility to periodontal disease.

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.

Antimicrobial susceptibility of periodontopathic bacteria associated with failing implants.

The aim of this study was to examine the subgingival microflora associated with failing implants, and to determine their susceptibility to commonly used antibiotics in periodontal therapy and dental practice. Thirteen partially edentulous patients with 19 failing implants were selected. Clinical examination included probing depth, attachment level, gingival index, plaque index, and radiographic analyses. Two subgingival plaque samples were taken from each failing implant and analyzed for microbial composition. Fusobacterium nucleatum, Porphyromonas gingivalis, and Prevotella intermedia were the prevalent cultivable microflora. Antimicrobial susceptibility of isolates was determined by the agar dilution technique. Antibacterial activity of penicillin G, amoxicillin, amoxicillin-clavulanate, and the combination amoxicillin-metronidazole was significantly higher than with other antibiotics tested. These data indicated that the commonly-used antibiotics were highly effective against bacteria isolated around failing implants, which would suggest the use of these antibiotics to control peri-implant infections.

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.

Effects of anesthetics containing epinephrine on catecholamine levels during periodontal surgery.

Nine stable cardiovascular disease patients were evaluated in a double-blind cross-over trial during periodontal surgery using 2% lidocaine with epinephrine 1:100,000 or lidocaine alone. In the lidocaine with epinephrine group, epinephrine levels increased from 198 +/- 54 pg/ml to 592 +/- 166 pg/ml at 2 minutes post-injection. In the lidocaine alone group, epinephrine levels increased from a baseline of 115 +/- 34 pg/ml to 150 +/- 34 pg/ml at 2 minutes post-injection. Despite these elevations in epinephrine, no significant changes in heart rate or mean arterial pressure were noted. Plain lidocaine provided unsatisfactory levels of hemostasis and/or anesthesia during periodontal surgery. This study documents acute elevations in plasma epinephrine levels following local dental anesthesia for periodontal surgery. These elevations in plasma epinephrine failed to produce a significant cardiovascular response in a group of stable cardiovascular disease patients. This suggests that the cardiac effects of local anesthetics containing epinephrine are small and that they can be safely used in stable cardiovascular disease patients.

Clinical and laboratory studies on human sclera allografts.

In the first section of this two-part report human peripheral blood leukocytes were tested for reactivity to extracts of sclera. Absence of scleral antigenicity is suggested by the results which showed that the leukocytes reacted similarly in sclera stimulated cultures and in the controls. The second part of the report discusses the clinical aspects of sclera allografts and provides guidelines for their clinical use. A case is presented where a sclera graft was in position for approximately a year. The tooth was removed with the attached graft and a histologic study made.

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.

Synergism of lysozyme, proteases and inorganic monovalent anions in the bacteriolysis of oral Streptococcus mutans GS5.

Streptococcus mutans GS5 was grown in synthetic medium containing radioactive thymidine to monitor deoxyribonucleic acid release. At neutral pH, cell lysis of hen egg-white lysozyme- or lysozyme-protease-treated cells was dependent upon the nature and concentration of the additive inorganic anions, HCO-3, SCN-, Cl- or F-. At acidic pH, NaHCO3, but not NaSCN, NaCl or NaF, was effective in promoting cell lysis which was due not only to the change in pH but also to the new HCO-3 anion concentration at the new pH. In both pH 4 and 5.2 reaction mixtures, the lysozyme and trypsin acted synergistically with NaHCO3 and the amount of lysis produced was markedly greater than in reaction mixtures containing lysozyme and bicarbonate but no protease. At apparent sub-lytic concentrations of NaHCO3, lysis was achieved by adding an appropriate concentration of one of NaSCN, NaCl or NaF to the lysozyme-protease-damaged cells. Thiocyanate proved to be most effective among the anions requiring lower concentrations to elicit lysis compared to chloride or fluoride for a fixed sub-lytic concentration of bicarbonate. As the NaHCO3 concentration increased, the lysis in the presence of these other anions increased until maximum levels of released deoxyribonucleic acid (DNA) were attained. In addition, the higher the NaHCO3 concentration, the more marked was the change in the degree of cell lysis. At a selected concentration at which NaHCO3 was not effective with any one salt, lysis could be achieved by combining all four inorganic anions at this concentration. The results suggest that the various anions present in oral fluids may together be sufficient to trigger lysis of oral microorganisms.

Lysozyme binding by a polyglycerol phosphate polymer of the oral bacterium Streptococcus mutans BHT.

The antibacterial properties of lysozyme for Streptococcus mutans BHT may be a function of its binding to cell components other than to peptidoglycan. Inhibitors of muramidase activity, including histamine and N-acetyl-D-glucosamine, only partially blocked the bacteriostatic effects on this strain. Greater than 20 mM histamine alone inhibited growth suggesting a bacteriostatic potential. An autoclaved saline extract was then prepared from stationary phase cultures in a chemically-defined medium. As little as 31.25 micrograms of the extract significantly blocked the effect of 50 micrograms lysozyme and complete enzyme inhibition was achieved with 62.5 micrograms. The extract was fractionated and location of potential binding components determined by a precipitin method consisting of diffusing the samples into 1.2 per cent agarose containing lysozyme. Binding components eluted in the first peak of a Sephacryl S-300 column, bound to DEAE-cellulose, but desorbed with gradient elution (0.1-1.0 M tris-HCl buffer, pH 8.0). The eluted material was then applied to an affinity column containing purified lysozyme coupled to epoxy-activated Sepharose 6B. Non-absorbed anionic material precipitated only with protamine. Lysozyme-binding fractions eluted in a sharp peak with 1.0 M tris-HCl buffer (pH 8.0), did not bind wheat-germ agglutinin, contained less than 50 micrograms protein, 95 micrograms sugar, 66.7 micrograms phosphorus, less than 0.25 mequiv lipid and no detectable nucleic acids. The peak material reacted with antiserum directed against polyglycerol phosphate, indicating that it contained acylated or, possibly, deacylated lipoteichoic acid. The findings suggest that the antibacterial properties of lysozyme for Strep. mutans BHT may, in part, be modified (or possibly regulated) by binding to molecules such as lipoteichoic acid.

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.

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.

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 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.