Delphi consensus statement for understanding and managing the subcostal hernia: subcostal hernias collaborative report (scholar study)

INTRODUCTION

Subcostal hernias are categorized as L1 based on the European Hernia Society (EHS) classification and frequently involve M1, M2, and L2 sites. These are common after hepatopancreatic and biliary surgeries. The literature on subcostal hernias mostly comprises of retrospective reviews of small heterogenous cohorts, unsurprisingly leading to no consensus or guidelines. Given the limited literature and lack of consensus or guidelines for dealing with these hernias, we planned for a Delphi consensus to aid in decision making to repair subcostal hernias.

METHODS

We adopted a modified Delphi technique to establish consensus regarding the definition, characteristics, and surgical aspects of managing subcostal hernias (SCH). It was a four-phase Delphi study reflecting the widely accepted model, consisting of: 1. Creating a query. 2. Building an expert panel. 3. Executing the Delphi rounds. 4. Analysing, presenting, and reporting the Delphi results. More than 70% of agreement was defined as a consensus statement.

RESULTS

The 22 experts who agreed to participate in this Delphi process for Subcostal Hernias (SCH) comprised 7 UK surgeons, 6 mainland European surgeons, 4 Indians, 3 from the USA, and 2 from Southeast Asia. This Delphi study on subcostal hernias achieved consensus on the following areas-use of mesh in elective cases; the retromuscular position with strong discouragement for onlay mesh; use of macroporous medium-weight polypropylene mesh; use of the subcostal incision over midline incision if there is no previous midline incision; TAR over ACST; defect closure where MAS is used; transverse suturing over vertical suturing for closure of circular defects; and use of peritoneal flap when necessary.

CONCLUSION

This Delphi consensus defines subcostal hernias and gives insight into the consensus for incision, dissection plane, mesh placement, mesh type, and mesh fixation for these hernias.

Complications of surgical extraction of ankylosed primary teeth and distal shoe space maintainers

The purpose of this report was to present the iatrogenic complications that may result from the management of ankylosed primary teeth as well as describe the case of a patient with an ankylosed primary mandibular left second molar which was surgically extracted and an adjacent primary first molar that was cemented with a distal shoe space maintainer. Aggressive surgical removal of the ankylosed tooth caused damage to the developing crown of the successor. Improper placement of the appliance caused perforation of the developing tooth follicle. Orthodontic therapy and a polycarbonate temporary crown were used to restore occlusion. Nonsurgical extractions and alternative appliances should be considered when treating patients with ankylosed primary second molars.

Assessment of a novel alternative to conventional formocresol-zinc oxide eugenol pulpotomy for the treatment of pulpally involved human primary teeth: diode laser-mineral trioxide aggregate pulpotomy

OBJECTIVE

The purpose of this study was to investigate whether a diode laser pulpotomy with mineral trioxide aggregate (MTA) sealing could be an acceptable alternative to the conventional formocresol pulpotomy and zinc oxide eugenol (ZOE) sealing in human primary teeth.

METHODS

A randomized, single-blind, split-mouth study was used with a sample of 16 children aged from 3 to 8 years (mean age=5.10 years). A total of 26 pairs of teeth from these 16 patients were selected based on clinical and radiographic criteria. One tooth from each pair was randomly assigned to either the laser-MTA pulpotomy group or the formocresol-ZOE pulpotomy group. All teeth were followed up clinically and radiographically at 2.3, 5.2, 9.5 and 15.7 months. All extracted failures were sectioned and photographed to assess possible reasons for this.

RESULTS

A total of seven laser-MTA-treated teeth were deemed to be radiographic failures (mean time until failure=9.1 months) compared to three formocresol-ZOE treated teeth (mean time until failure=12.5 months). These results were not significant using Fisher's exact test (P>0.05). Six of the laser-MTA failures and all three formocresol-ZOE failures exhibited furcal and/or periapical radiolucencies with or without pathologic root resorption. One of the laser-MTA failures displayed premature root resorption and is being observed for exfoliation. Analysis of photographs of teeth available for extraction revealed errors in clinical technique in addition to expected signs of a disease process such as the presence of granulation tissue and areas of pathologic root resorption.

CONCLUSIONS

The laser-MTA pulpotomy showed reduced radiographic success rates compared to the formocresol-ZOE pulpotomy at 15.7 months; however, these results were not statistically significant. Improved success rates among a larger patient sample and a longer follow-up period would be required for the laser-MTA pulpotomy to be considered a routine alternative to the conventional formocresol-ZOE procedure. Meticulous restorative techniques must be followed to ensure the success of laser-MTA pulpotomies.

Promotion of selective cell attachment by the RGD sequence in dentine matrix protein 1

Dentine matrix protein 1 (DMP1) is an important component of the non-collagenous extracellular matrix of developing teeth and bones. Functions of DMP1 other than a putative role in the initiation of mineralization are largely unknown. A first report on the DNA and deduced amino acid sequence showed that DMP1 has a single Arg-Gly-Asp (RGD) sequence. Here, whether the RGD sequence functions as a cell-attachment domain was tested. Using site-directed mutagenesis, two mutant recombinant DMP1 proteins with specific alterations at the RGD site were created. In the first mutant protein the RGD sequence was altered to a RGE (RGE) sequence; in the second the RGD domain was deleted (DEL). Mutated proteins were confirmed to be DMP1 by partial protein sequencing and dot-blot analysis with an anti-DMP1 antibody. Attachment of RPC-C2A (dental pulp cells), MC3T3-E1 (calvarial cells) or CHO (Chinese hamster ovary cells) to non-tissue-culture plastic coated with either DMP1, RGE or DEL proteins was compared. Bovine serum albumin and fibronectin served as negative and positive controls, respectively. The RGD-containing native DMP1 protein effectively allowed cell attachment and spreading. The RGE and DEL proteins with the altered and deleted RGD sites were significantly less effective in promoting cell attachment than the recombinant DMP1. Both RPC-C2A pulp cells and MC3T3-E1 cells showed similar reductions in attachment to mutated proteins. Treatment of RPC-C2A cells with a RGD-containing peptide prior to plating on DMP1-coated chambers abolished DMP1-mediated cell attachment. In contrast to RPC-C2A and MC3T3-E1cells, CHO cells, which normally do not express DMP1, failed to attach to DMP1. These data demonstrate that DMP1 promotes cell attachment through the RGD domain and that the attachment is cell- and tissue-specific. A basis for these observations is proposed using computer-generated models of the polypeptides within the DMP1 protein containing the RGD, RGE or DEL sequences.

Optimization of a procedure for rebonding dislodged orthodontic brackets

The purpose of this study was to compare shear bond strength (SBS) of bonded and rebonded orthodontic brackets following a variety of commonly used conditioning treatments and using both light-cured and self-cured composite resin systems. Brackets debonded during the initial determination of SBS were rebonded after the removal of residual resin from enamel surfaces using five different treatments: (1) Remove residual resin using a tungsten carbide bur, re-etch enamel surface, then bond a new bracket; (2) Remove resin from the base mesh with micro-etching then rebond the same bracket, (3) Remove residual resin from the enamel surface using resin-removing pliers, recondition the enamel with an air-powder polisher, then bond a new bracket; (4) Remove residual resin using a rubber cup and pumice, then bond a new bracket; (5) Remove residual resin using pliers alone, then bond a new bracket. The results revealed that the light-cured system produced higher shear bond strength in the initial bond than the self-cured system (p<0.005). Reconditioning the enamel surfaces using a tungsten carbide bur and acid-etching gave the highest SBS (difference 5.8 MPa; p<0.01) and clinically favorable fracture characteristics. The data suggest that the optimal procedure for rebonding dislodged orthodontic brackets is to resurface the enamel using a tungsten carbide bur, acid-etch the enamel, and use a new or re-use an old bracket after microetching.

Role of mitochondrial membrane potential in concanavalin A-induced apoptosis in human fibroblasts

Lectins induce apoptosis in a wide variety of cell types but the mechanisms of apoptotic induction are unknown. We examined the role of mitochondrial membrane potential (Psi m) in concanavalin A-induced apoptosis in human diploid fibroblasts. Cells were treated with Con A for 0.5, 1, 3, 5, and 24 h. Con A induced a time-dependent increase of the proportion of TUNEL+ ve cells over 24 h. Psi m was examined by staining cells with the mitochondria-specific fluorescent cationic dye JC-1. Comparison of JC-1 fluorescence within mitochondria by flow cytometry showed that after 3 h, Con A reduced Psi m in a subpopulation of apoptotic cells with smaller cell volume and with apoptotic nuclear morphology. In contrast, Psi m was unchanged in a separate population of viable cells with normal volume and normal nuclear morphology. Cyclosporin A protected cells against reduction of Psi m and also against nuclear condensation and morphological apoptosis. Measurement of intracellular calcium ion concentration ([Ca2+]i) by ratio fluorimetry of fura 2-loaded cells showed that Con A did not affect [Ca2+]i in viable cells but induced a progressive depletion of [Ca2+]i with generation of calcium oscillations in apoptotic cells. Assessment of Bcl-2 in Con A-treated cells demonstrated an initially strong increase in Bcl-2 protein and mRNA but the appearance of degraded Bcl-2 protein at 3 and 5 h after treatment, indicating an inadequate protective response to the Con A stimulation. Collectively, these data indicate that lectin-induced apoptosis in fibroblasts is associated with breakdown of Psi m, loss of [Ca2+]i homeostasis, and induced Bcl-2 expression.

The effect of various storage methods and media on shear-bond strengths of dental composite resin to bovine dentine

A variety of media and methods have been used to store teeth used in bond-strength studies of resin restorative materials to dentine. This study examined the effect of 2 months of storage using 11 different methods and media on the shear-bond strength of Z100 resin composite to bovine dentine mediated by Scotchbond Multi Purpose adhesive. Freshly harvested teeth were used as controls. The results showed that 7 of the l1 storage methods or media were similar in shear-bond strengths and bond-failure characteristics. Four of the 11 methods (irradiation, or storage in thymol, methanol, and glutaraldehyde) resulted in significantly lower shear-bond strengths and atypical shear-bond failure, indicating that these are the least desirable methods of tooth storage for studies of this type. This study has further shown that if insufficient numbers of fresh teeth are available for studies of shear-bond strength, then freezing is the preferred method of storage for the registration of high shear-bond strengths. It is also apparent that further investigations are needed to examine what post mortem changes occur in dentine, whether these changes are modified by various storage conditions, and whether they have any significant effect on bonding of resin composites.

Paclitaxel selectively induces mitotic arrest and apoptosis in proliferating bovine synoviocytes

OBJECTIVE

Rheumatoid arthritis (RA) is characterized by chronic progressive destruction of joints involving several disease processes, such as villous hypertrophy, proliferation of synovial lining cells, and infiltration of inflammatory cells. Synovial cell activation and proliferation is thought to be a key step in the destruction of cartilaginous and bony tissues in RA joints. In view of the invasive properties of synoviocytes in RA, we conducted in vitro studies to determine the mechanism of action of paclitaxel (Taxol) on synoviocytes, which may account for the inhibition of joint destruction found when this agent is administered.

METHODS

Cultured synovial cells were treated with various concentrations of paclitaxel and were evaluated by cell viability, fluorescence microscopy, flow cytometry of DAPI-stained cells, and electron microscopy.

RESULTS

The data indicated that paclitaxel inhibited synoviocyte proliferation by a G2/M phase block and was toxic to synoviocytes by inducing apoptosis. Confluent cells such as chondroyctes and synoviocytes were not affected by paclitaxel. Synchronization of synovioyctes at the G1/S boundary effectively abolished paclitaxel-induced apoptosis.

CONCLUSION

The data indicate that induction of apoptosis in synoviocytes might be dependent on transit through the cell cycle, specifically through G2 and mitosis. Further, paclitaxel was selectively toxic to proliferating synoviocytes but spared nonproliferating synoviocytes and chondrocytes. These results demonstrate that paclitaxel can inhibit synovial cell proliferation and pannus formation in RA joints in vivo. We suggest that paclitaxel be considered as a prototypical compound for a new class of potential chondroprotective agents.

Concanavalin A induced apoptosis in fibroblasts: the role of cell surface carbohydrates in lectin mediated cytotoxicity

Cell surface carbohydrates play important regulatory roles during development and in tissue homeostasis by mediating cellular signalling. Concanavalin A (con A) cross links mannose residues on cell surfaces. We used con A to examine the role of cell surface carbohydrates in apoptosis. Balb/c 3T3 (3T3) and diploid human gingival fibroblasts (HGF) incubated with con A (50 micrograms/mL) exhibited rounding, reduction of cell size, loss of cytoskeletal definition, nuclear condensation, and ultrastructural changes consistent with apoptotic cell death. However oligonucleosomal DNA fragmentation was not observed. The sugar methyl-alpha-D-mannopyranoside (MADM) competes for binding sites with con A but failed to induce apoptosis. Cell survival assays after con A treatment demonstrated a concentration dependent (5-500 micrograms/mL) loss of cell viability in 3T3 and HGF cells which was blocked by MADM. The relationship between cell surface binding of con A and cell death was studied in 3T3 cells labelled with varying concentrations of FITC-con A. Flow cytometry and cell survival analyses revealed that smaller cells with lower total cell surface FITC-con A binding sites were approximately 8 times more susceptible to cell death than larger cells with higher number of binding sites. This suggests a positive relationship between cell size, number of con A binding sites, and cell death. Flow cytometric cell cycle analysis of HGF cells showed a 46% reduction in the proportion of G1 phase cells but there was little change in the relative proportions of S and G2+M phase cells. 3H-thymidine labelling of con A treated cells showed a five-fold decrease (chi sq; P < 0.05) in the percentage of labelled cells, indicating blockade of cell cycle transit into S. Thus, cell death occurred predominantly in G1, possibly due to inhibition of protein synthesis which in turn prevented entry of cells into S phase. 35S-methionine uptake in con A treated cells was significantly reduced (approximately 42% con A 50 micrograms/mL; approximately 67% con A 500 micrograms/mL; P < 0.05) compared to untreated controls indicating inhibition of de novo protein synthesis. SDS-PAGE of total cellular proteins confirmed reduction of predominantly lower molecular mass proteins after con A treatment. Con A treatment (50 micrograms/mL) induced a 25% reduction of free intracellular calcium ion concentration over 30 min suggesting that calcium dependent enzymes and translational mechanisms may be inhibited. Collectively, these results indicate that con A binding of cell surface carbohydrates can induce apoptotic cell death in fibroblastic cells due in part to protein synthesis inhibition.

Serum deprivation induces apoptotic cell death in a subset of Balb/c 3T3 fibroblasts

Little is known about the regulation of apoptosis in fibroblasts although several model systems including serum deprivation and treatment with staurosporine or topoisomerase inhibitors have been used to induce apoptosis in vitro. To validate a reproducible in vitro model for the study of apoptosis in fibroblasts, we cultured density-inhibited monolayer cultures of Balb/c 3T3 fibroblasts in Dulbecco's modified essential medium plus 15% fetal calf serum and then withdrew serum. Time-lapse video microscopy demonstrated that within minutes of serum withdrawal, cells lost substrate attachment and floated to the top of the liquid growth medium. There was a time-dependent increase in the number of non-adherent cells. Some of these cells regained attachment and spread momentarily, but they eventually rounded up and lost attachment permanently. In contrast to serum-containing cultures in which similar morphological changes were followed by mitosis, in serum-free cultures repeated attempts at mitosis were followed by permanent attachment loss and presumably cell death. To assess whether all the non-adherent cells were in fact dead, the percentages of cells that continued to proliferate upon return to serum-supplemented conditions was computed. After various periods of serum starvation a decreasing proportion (approx. 75% at 30 minutes; &lt; 2% at 24 hours) of the non-adherent cells could be rescued by addition of serum. Transmission electron microscopy of cells 3 hours after serum withdrawal showed that the majority (approximately 60%) of non-adherent cells exhibited marked intranuclear chromatin condensation but maintained integrity of cell and nuclear membranes and cell organelles, morphological changes consistent with those of apoptotic cell death. Scanning electron microscopy of cultures 3 hours following serum withdrawal showed rounded cells with marked surface blebbing. Fluorescence and confocal microscopy revealed increased intensity of nuclear staining with DAPI while actin filaments became indistinct or collapsed around the nucleus. After cycloheximide treatment to inhibit protein synthesis, there was no reduction of apoptosis. Gel electrophoresis of DNA from both control and 3 hour-serum-deprived cells showed intact DNA with no oligonucleosomal length fragmentation. After serum withdrawal, intracellular calcium was reduced by about 32% over 5 minutes as measured by fura2 ratio fluorimetry in single cells. Serum-starved cells showed a time-dependent shrinkage in mean cell diameter compared to trypsinized, adherent control cells (at 0 hours, mean diameter = 18.0 microns--viable; at 4 hours, mean diameter = 15.5 microns--apoptotic). Flow cytometric analysis showed increased propidium iodide staining and reduced fluorescein diacetate uptake over 3 hours, changes that were contemporaneous with the reduction of cell diameter.(ABSTRACT TRUNCATED AT 400 WORDS)

Proliferative responses of endothelial cell populations to experimentally induced inflammatory lesions of gingival connective tissues in the cynomolgus monkey (Macaca fascicularis)

BACKGROUND

Endothelial cells exhibit heterogeneous and tissue-selective responses to injury and inflammation. The regulation of the size of endothelial populations in specific tissue sites is poorly characterized, particularly in soft connective tissues adjacent to bone. To investigate the effect of a primarily lymphocytic infiltrate on endothelial cell proliferation and growth of blood vessels, a primate model was used that reliably exhibits localized, distinct inflammatory, and destructive lesions in isolated sites of mucosal connective tissues adjacent to bone and epithelium around teeth.

METHODS

Three Cynomolgus monkeys with healthy periodontium and two with spontaneously occurring inflammation or induced connective tissue destruction were pulse labeled with 3H-thymidine. Morphometric analyses of radioautographs from mid-sagittal supra-alveolar gingival connective tissues of incisor teeth were performed in sites subjacent to junctional, sulcular, and oral epithelium, in the body of the lamina propria and just superior to the alveolar bone crest.

RESULTS

Subjacent to the sulcular epithelium there was a statistically significant (P < 0.01) increase in lymphocyte density between health and inflammation. The percentage of endothelial cells incorporating 3H-thymidine label (LI) and the number of blood vessels per unit area were significantly increased in this same site in inflamed samples (P < 0.02) but were not elevated further in lesions in which there was destruction of soft connective tissues. However, there was no increase of the numbers or the cross-sectional areas of blood vessels between samples of inflamed and destroyed tissues.

CONCLUSIONS

1) Experimentally induced inflammation and connective tissue destruction in the gingival connective tissues of Cynomolgus monkeys is associated with site-specific perturbations in the turnover of endothelial cells that is closely linked to lymphocytic infiltration; 2) the vascular response is a generalized increase in endothelial cell proliferation and blood vessel numbers but not lumen size or number of endothelial cells, suggesting the existence of homeostatic controls for preservation of the whole population in a steady state.

Probing velocity: novel approach for assessment of inflamed periodontal attachment

Little is known about the biophysical characteristics of the dento-gingival junction in response to the development or resolution of inflammation. The Toronto automated periodontal probe (TAPP) provides an estimate of the biophysical integrity of the dento-gingival junction by measuring intrapocket probing velocity. Presence or absence of a plateau in displacement versus time plots were used to perform dichotomous analyses as a function of established parameters of inflammation. Plateaus were operationally defined as a 3 standard deviation reduction in the slope of the displacement versus time plot (probing velocity) and hence the plateau represents an increased resistance of the probe tip at the dento-gingival junction. The aim of the study was to measure the relationship between post-treatment reductions of gingival inflammation and the probability of plateau formation as measured by the TAPP. Twenty-nine subjects exhibiting gingival inflammation were provided with periodontal therapy consisting of subgingival scaling and root planing. Over a 2-month sampling period, 6 sites from each subject were monitored and these sites exhibited wide variations of inflammation. Logistic regression revealed a significant relationship between the probability of plateau formation and treatment (P = 0.002), plaque index (P = 0.002), the increased severity levels of gingival index (P > 0.05), or bleeding index (P > 0.05). The probability of plateau formation decreased with higher levels of crevicular fluid flow but there was no dependence of plateau formation on probing depth (P > 0.55). These data indicate a direct relationship between improved measures of clinical health and increased resistance to probe penetration near the base of the pocket.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship of oral malodor to periodontitis: evidence of independence in discrete subpopulations

Associations between oral malodor, measures of periodontal disease, and trypsin-like activity of periodontal pathogens on tongue and teeth were examined in 127 subjects. Volatile sulphur compound (VSC) measurements were made with a portable sulphide monitor; oral malodor was also estimated by organoleptic methods. Measurements repeated one week apart indicated that steady-state VSC levels (r = 0.72; P = 0.0001) and peak VSC levels (r = 0.63; P = 0.0001) were reproducible but these r values were not significantly different (P > 0.1). There was a significant correlation between tongue odor and peak VSC levels (r = 0.40; P = 0.0001) and between tongue odor and whole mouth organoleptic measures (r = 0.55; P = 0.0001). To study the effect of reducing microbial colonization on oral malodor, chlorhexidine gluconate (0.2%) rinsing was prescribed for 7 days. Reductions of VSC levels were significant for both peak (37%) and steady-state (41%) data (P = 0.0001). Anaerobic periodontal pathogens on the tongue estimated by the proportions of positive BANA tests were reduced 19% (P = 0.001) and this was concomitant with a 40% (P = 0.0001) decrease in organoleptic measurement of the tongue dorsum. Mean pH measurements of the tongue dorsum showed large reductions from 6.9 initially to 6.3 post-treatment (P = 0.0001). Subjects were divided into periodontitis/no periodontitis based on periodontal inflammation and probing depth (> or = 5 mm). Of the 37 subjects with periodontitis, 23 had oral malodor whereas 52 out of 90 periodontally healthy subjects exhibited malodor. Chi square analysis comparing halitosis in subjects with and without periodontitis showed no statistically significant association (chi 2 = 0.208; P 0.65) between these two factors although the intensity of malodor as based on VSC concentration in periodontally healthy subjects was 19% less (mean = 111 ppb) than in subjects with periodontitis (mean = 136 ppb). The odds ratio was 1.2, indicating that oral malodor was not associated with periodontitis. These data indicate that a large proportion of individuals with oral malodor are periodontally healthy and that the mucosal surface of the tongue is a major site of oral malodor production.

Fragile X (Martin-Bell) syndrome

Fragile X syndrome is a common condition resulting from a cytogenetic abnormality in the X chromosome. Mental retardation, characteristic facies, and large testes are some of the most important characteristics of the condition. The relatively high incidence of the syndrome--approximately one per thousand--the high incidence of cardiac anomalies in these individuals, the oral and facial features associated with the condition, and the paucity of reported cases in the dental literature make it particularly interesting to dentistry. Here we report the case of a 12-year-old male, including the cytogenetic and cephalometric analyses, presenting with some of the classic features and some features not commonly reported.

Relationship between periodontal probing velocity and gingival inflammation in human subjects

Little is known about the biophysical characteristics of the dentogingival junction in response to the development or resolution of inflammation. The Toronto Automated Periodontal Probe (TAPP) provides an estimate of the integrity of the dentogingival junction by measuring intrapocket probing velocity. The aim of this study was to measure changes of probing velocity in inflamed human periodontium before and after subgingival debridement. 32 subjects exhibiting gingival inflammation were selected; 29 completed the study. Gingival index (GI), plaque index (PLI), bleeding index (BI) and the rate of gingival crevicular fluid flow (CFF) were measured as concomitant variables. The experimental group (N = 16) received scaling, root planing and oral hygiene instruction at baseline. The control group (N = 13) received no treatment until after 28 days. Subjects were seen at baseline, day 14, 21 and 28 for measurement of probing velocity and concomitant variables on 6 index teeth. At day 28, the control group was treated and then reassessed 28 days later. The experimental group showed a reduction of 51.6% for mean crevicular fluid flow (p < 0.0001), 79.7% for mean plaque index (p < 0.0001), 58.0% for mean gingival index (p < 0.0001), and 72.0% for mean bleeding index (p < 0.01) at day 28, confirming that inflammation was reduced compared with baseline. No significant changes were observed in the control group until after treatment. The velocity of probing and the formation of a plateau in the velocity profile were recorded.(ABSTRACT TRUNCATED AT 250 WORDS)

Serial doxycycline and metronidazole in prevention of recurrent periodontitis in high-risk patients

The efficacy of metronidazole and doxycycline in preventing recurrent periodontitis was studied in 23 patients. After treatment in the previous 7 months with either bimonthly scaling and 3 weeks of systemic doxycycline (11 subjects) or scaling and placebo (12 subjects), patients were monitored for recurrent periodontitis and were scaled every 2 months. When either a periodontal abscess or greater than 2 mm loss of gingival attachment was observed, metronidazole was administered (250 mg every 8 hours) for 10 days. In the placebo plus metronidazole group, 5 patients (42%) exhibited recurrent periodontitis after the metronidazole regimen compared with only one (9%) in the doxycycline plus metronidazole group (P less than 0.096). Subgingival plaque samples at study and healthy control sites were screened for the presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Eikenella corrodens, and Fusobacterium nucleatum by immunofluorescence and for spirochetes using Ryu's stain. Presence/absence analysis of the sum of scores of the 6 individual pathogens demonstrated large reductions (P less than 0.005) in the frequency of detection of pathogens in the former doxycycline compared with the placebo plus metronidazole group at both study and control sites before and one month after metronidazole. By 7 months after metronidazole, there was no detectable difference between groups. These results indicate that prevention of recurrent periodontitis with metronidazole may be enhanced by previous treatment with doxycycline.

Reproducibility and sensitivity of oral malodor measurements with a portable sulphide monitor

Forty-one subjects with bad breath were assessed for oral malodor and periodontal status on three occasions, at intervals of approximately one week. Oral malodor was assessed by measurement of peak and steady-state volatile sulphide levels with a portable sulphide monitor and by organoleptic measurement of whole-mouth, tongue dorsum, and interproximal dental odors by two independent judges. Reproducibility of measurements, assessed by paired t tests and Kappa testing, demonstrated no significant differences between any of the test results from the first and second appointments. Steady-state sulphide levels were the most reproducible of all tests. The ability of the tests to detect an expected reduction of malodor following a 0.2% chlorhexidine mouthrinse regimen was investigated by comparison of test values between the second and third appointments. Following the mouthrinsing treatment, 43% reductions of peak, 47% reductions of steady-state volatile sulphide levels, and 15-58% reductions in all other measurement categories were observed. The majority of the participants (22/41) had no pockets greater than 5 mm and exhibited both moderate gingival inflammation (Mean Gingival Index = 1.17) and moderate plaque accumulation (Mean Plaque Index = 1.84). Plaque Index and presence of pockets greater than 7 mm were weakly related to sulphide measurements. Whereas assessment of steady-state sulphide levels by the sulphide monitor does not constitute a direct measure of oral malodor, its relation to organoleptic measurement, superior reproducibility, objectivity, and sensitivity support the use of the sulphide monitor in clinical studies.

A randomized, placebo-controlled trial of doxycycline: effect on the microflora of recurrent periodontitis lesions in high risk patients

Twenty-seven patients with a recent history of periodontal abscesses and/or loss of gingival attachment level (GAL) despite active periodontal therapy were enrolled in a double-blind, randomized, placebo-controlled trial. Clinical measurements and subgingival scaling were performed every 2 months. When a site exhibited greater than or equal to 2 mm loss of GAL or a periodontal abscess, patients were administered either doxycycline at a dosage of 200 mg to start and 100 mg per day for 3 weeks, or a placebo. Clinical measurements of GAL and microbial analysis of subgingival plaque at study and control sites were made at the time of active disease and at intervals of 1 week and 7 months after completion of the drug regime. Plaque samples were screened for the presence of Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Bacteroides intermedius (Bi), Eikenella corrodens (Ec) and Fusobacterium nucleatum (Fn) by indirect immunofluorescence antibody technique and for spirochetes (Sp) using Ryu's stain. Based on presence or absence analysis of the sum scores of the 6 pathogens, both the placebo (n = 10) and the doxycycline groups (n = 17) exhibited similar scores at the time of detection of active disease (mean placebo = 2.38 +/- 0.32; mean doxycycline = 2.95 +/- 0.27; P = 0.18). One week after treatment, the probability of detection was unchanged in the placebo group (mean placebo = 3.14 +/- 0.47), but was significantly reduced in the doxycycline group (mean doxycycline = 1.77 +/- 0.26; P = 0.0002). Study (active) sites exhibited scores 2 to 3 times higher than control (inactive) sites before doxycycline treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

An investigation into the use of restriction endonuclease analysis for the study of transmission of mutans streptococci

Restriction endonuclease analysis (REA) was performed on the total cellular DNA from each of 396 strains of mutans streptococci (1) to determine its potential usefulness for the study of transmission of the organism and (2) to document the proportions and variety of strains harbored by members of a small group of families. The DNA was digested with restriction enzyme EcoRI and/or HindIII, electrophoresed on agarose gels, and the resulting patterns compared. The strains examined included fresh isolates from 58 subjects, including 19 strains from each member of five families. The sensitivity and reproducibility of REA patterns from the mutans streptococci seemed ideal for studies of their epidemiology and transmission. The pattern of each isolate from humans was unique, except for isolates from the same individual or from the same family. REA types from subjects from different families were always heterogeneous. A high frequency of multiple REA types (up to 5) was observed in many subjects. While evidence for intra-familial transmission was obtained, including transmission between spouses, there was also strong evidence of frequent sources of infection outside of the family. Mutations of strains to streptomycin resistance or to lactate dehydrogenase deficiency caused no detectable change in the REA patterns. The lack of plasmids in any of the 57 fresh isolates that were examined for them suggested that they may have contributed little to the heterogeneity of the patterns seen.