Molar Sites Research Articles

Human salivary function in relation to the prevalence of Tannerella forsythensis and other periodontal pathogens in early supragingival biofilm

Objective: Previously, we screened 149 subjects and established four groups high or low for salivary killing of oral bacteria, and for aggregation and live and dead adherence of oral bacteria (as a combined factor). Caries scores were significantly lower in both High Aggregation–Adherence groups. Subsequently, we found that supragingival total biofilm DNA, total streptococci and two major streptococcal rRNA variants also were significantly lower in the High Aggregation–Adherence groups. In this study, we looked at the effects of those differences in salivary function on three periodontal pathogens. Design: Quantitative PCR was used to determine levels of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythensis (formerly Bacteroides forsythus) in stored DNA extracts of overnight supragingival biofilm collected from buccal upper central incisors (UC), lingual lower central incisors (LC) and buccal upper and lower first molars (BM) and lingual upper and lower first molars (LM) of subjects in the four groups. Results: A. actinomycetemcomitans and P. gingivalis were almost completely absent from these samples. T. forsythensis was found in 11 of 35 persons at the buccal molar site. Only two of those subjects were in the High Aggregation–Adherence groups, and that difference was statistically significant. The mean quantity of T. forsythensis also was significantly lower in the High Aggregation–Adherence groups. Conclusions: The difference between the Low and High Aggregation–Adherence groups might reflect direct interactions of salivary proteins with T. forsythensis. Alternatively, the higher levels of total biofilm and total streptococci seen in the Low Aggregation–Adherence groups might create a favourable environment for early secondary colonization of T. forsythensis.

Effects of Drying Time and the Presence of Plaque on the in vitro Performance of Laser Fluorescence in Occlusal Caries of Primary Teeth

The diode laser fluorescence device was introduced to diagnose caries lesions in occlusal and smooth surfaces. Despite promising results, much variation has been found in the protocol of utilization. The goal of this study was to evaluate the influence of dental plaque and drying time on the laser fluorescence (DIAGNOdent) performance in occlusal sites of primary molars. For the drying time study, 63 suspected occlusal sites in primary molars were used. The same sites were evaluated in four different conditions: (1) moist teeth, (2) teeth dried for 3 s with a 3-in-1 syringe, (3) teeth dried for 15 s, and (4) dehydrated teeth. For the plaque experiment, we selected 28 occlusal sites. After the baseline laser fluorescence readings, plaque collected from children was placed on the suspected site. New laser fluorescence measurements were performed. For both studies, we compared the laser fluorescence values, as well as sensitivity, specificity, accuracy, and area under ROC curve. For different drying times, the more dehydrated the teeth, the higher the values. Nevertheless, the performance of the method did not change significantly, except for dehydrated teeth. In the presence of plaque, the laser fluorescence values were reduced, and the evaluated parameters were worse than with no plaque. In conclusion, the hydration state of the teeth did not change the results significantly, but the presence of plaque worsened the performance of the laser fluorescence method.

The high frequency of Porphyromonas gingivalis, Prevotella intermedia, and Prevotella nigrescens in subgingival plaque may be associated with periodontal diseases in subjects aged 30 to 49 years

A total of 299 subjects (156 males, 143 females, aged 6 to 0689 69 years) were randomly chosen from Meikai University Hospital, Saitama, Japan. To be included, subjects had to have at least 20 teeth, including all first molars. Subjects who smoked were excluded, as were those with aggressive periodontitits, periodontitis as a manifestation of systemic diseases, acute necrotizing periodontal diseases, periodontal or antibiotic therapy in previous 5 months, pregnancy, systemic conditions that could influence periodontal status, or problems arising from residential location. Suspected etiology was the occurrence of periodontal 0689 pathogens ( Porphyromonas gingivalis, Prevotella intermedia, P nigrescens ) in subgingival plaque collected from the most inflamed site among 4 mesiobuccal sites of first molars. The presence of these pathogens was detected by immunoslot blot assay (IBA). The reactivity of the assay was classified as positive when the intensity of the bacterial sample was ≥1 × 10 6 cells. Pocket depth.0689 The presence of periodontal pathogens in subgingival 0689 plaque did not affect the mean poeket depths in any age group. In other words, there were no differences in the mean pocket depths between sites with positive and negative reactivity to P gingivalis, P intermedia , or P nigrescens . Mean pocket depth increased with increasing age. The frequency of P gingivalis -positive plaque also appeared to increase with increasing age. The percentages of P gingivalis -positive plaque in subjects aged 30 to 39, 40 to 49, 50 to 59, and 60 to 69 were significantly higher than those in subjects aged 20 to 29 ( P < 0.01 ).

Streptococcal diversity in oral biofilms with respect to salivary function

Objective: In a previous study, we screened 149 subjects and established four groups high or low for salivary killing of oral bacteria, and for aggregation and live and dead adherence of oral bacteria (as a combined factor). Caries scores were significantly lower in both High Aggregation–Adherence groups. In this study we looked at the effects of those differences in salivary function on the quantity and diversity of oral biofilm streptococci. Design: Subjects from those four groups were recalled for collection of overnight oral biofilm from buccal upper central incisors, lingual lower central incisors, buccal upper and lower first molars, and lingual upper and lower first molars. At each site, groups were compared for total biofilm (by DNA concentration), total streptococci (by quantitative PCR), and streptococcal diversity (by Streptococcus-specific denaturing gradient gel electrophoresis). Results: Total biofilm DNA and total streptococci were correlated. Both were highest on buccal molar surfaces and lowest on lingual lower central incisors, and both were significantly lower in the High Aggregation–Adherence groups (particularly at the buccal molar site). Fifty distinct bands were observed in denaturing gradient gels. There was great diversity within and between sites. Three major bands were present in almost every person at every site. Densities for two of those bands were significantly lower in both High Aggregation–Adherence groups. Other less-prevalent bands also showed the same pattern. Conclusion: These findings are consistent with our caries results in suggesting that differences in salivary function can influence the quantity and composition of streptococci in oral biofilms.

Radiographic alveolar bone loss in untreated Taiwan Chinese subjects with adult periodontitis measured by the digital scanning radiographic image analysis method.

To determine differences in radiographic alveolar bone loss (RABL) by age group, gender and tooth type in subjects with adult periodontitis using the digital scanning radiographic image analysis (DSRIA) method. A total of 4262 teeth were examined for RABL in 178 individuals (96 males and 82 females). Mesial and distal sites were determined by the DSRIA method following scanning of periapical radiographs and using the Microstation 95 image software. Linear assessment of RABL using DSRIA revealed the following results. Mean bone loss of maxillary and mandibular anterior teeth was significantly higher (P<0.001 and P<0.01, respectively) in males compared with females using a two-sample t-test. The highest values of mean RABL occurred most commonly in the maxillary first molars (53.8% and 51.4% for females and males, respectively) and the mandibular central incisors (50.4% and 41.5% for males and females, respectively). Mean RABL was greater in males than in females for both the mandibular and maxillary arches, with the exception of molar sites. Maxillary first molars and mandibular incisors are the highest risk sites. Moreover, greater loss occurs at the molar site in females compared with males for untreated periodontitis in Taiwan Chinese people.

An in vitro Comparison of a Combined FOTI/Visual Examination of Occlusal Caries with Other Caries Diagnostic Methods and the Effect of Stain on Their Diagnostic Performance

The aims of this in vitro study were to compare the combination of FOTI and visual inspection to other diagnostic methods for the detection and evaluation of the depth of occlusal caries and assess the effect of stain on diagnostic performance. Five diagnostic methods (combined FOTI/Visual (CFV), Visual, FOTI, DIAGNOdent and Electrical Caries Monitor) were considered. Histological validation was performed in the 152 occlusal molar sites (111 teeth) using 350-µm sections and a stereomicroscope. The rank correlation coefficients with histology ranged from 0.42 (DIAGNOdent) to 0.66 (CFV). The area under the ROC curves (AUC) for enamel lesions ranged from 0.82 (ECM) to 0.88 (CFV) and from 0.81 (DIAGNOdent) to 0.91 (CFV) for dentine lesions. The AUC at the dentine level for CFV and FOTI were similar (p > 0.05), but the AUC for CFV was significantly greater than for visual (p < 0.001), DIAGNOdent (p = 0.005) and the ECM (p = 0.04). FOTI was found to be particularly useful for the detection of dentine lesions. The exclusion of stain and brown spot lesions improved performance for all methods. It is concluded that CFV is useful for the determination of occlusal lesion depth and that in the presence of stain and brown spot lesions different cut-off points may be required for the ECM and DIAGNOdent to identify dentine lesions.

Human mineralized bone in extraction sites before implant placement: Preliminary results

Bone loss after tooth extraction may prevent dental implant placement. Human mineralized bone grafts can be used to restore bone volume and allow for tooth replacement with dental implants. The authors grafted 22 sites in 18 patients with human mineralized bone after tooth extraction. They allowed molar sites 16 weeks for graft healing, placed the implants and restored them with a final crown after a four-month integration period. Single-rooted maxillary sites received implants and immediate placement of provisional crowns or underwent a delayed two-stage restoration approach. The authors used radiographs and clinical examinations to evaluate the results. All of the sites were restored successfully with a single-tooth implant restoration. Periapical radiographs indicated that the crestal bone levels were limited to the first thread of the implants or slightly coronal to the first thread of the implant. Clinical evaluation indicated excellent gingival health around the provisional and final restorations, without obvious gingival migration. The use of human mineralized bone may have significant potential to reconstruct missing bone resulting from tooth extraction and to preserve bone after tooth extraction. In addition, healed bone graft sites seem to be able to support immediate placement of a provisional crown and implant restorations. Patients who are having teeth extracted may become candidates for implant restorations when the sites are appropriately grafted to preserve and reconstruct bone volume, thus allowing for more options for reconstructing the missing tooth site.

Rescue of cleft palate in Msx1-deficient mice by transgenic Bmp4 reveals a network of BMP and Shh signaling in the regulation of mammalian palatogenesis.

Cleft palate, the most frequent congenital craniofacial birth defects in humans, arises from genetic or environmental perturbations in the multi-step process of palate development. Mutations in the MSX1 homeobox gene are associated with non-syndromic cleft palate and tooth agenesis in humans. We have used Msx1-deficient mice as a model system that exhibits severe craniofacial abnormalities, including cleft secondary palate and lack of teeth, to study the genetic regulation of mammalian palatogenesis. We found that Msx1 expression was restricted to the anterior of the first upper molar site in the palatal mesenchyme and that Msx1 was required for the expression of Bmp4 and Bmp2 in the mesenchyme and Shh in the medial edge epithelium (MEE) in the same region of developing palate. In vivo and in vitro analyses indicated that the cleft palate seen in Msx1 mutants resulted from a defect in cell proliferation in the anterior palatal mesenchyme rather than a failure in palatal fusion. Transgenic expression of human Bmp4 driven by the mouse Msx1 promoter in the Msx1(-/-) palatal mesenchyme rescued the cleft palate phenotype and neonatal lethality. Associated with the rescue of the cleft palate was a restoration of Shh and Bmp2 expression, as well as a return of cell proliferation to the normal levels. Ectopic Bmp4 appears to bypass the requirement for Msx1 and functions upstream of Shh and Bmp2 to support palatal development. Further in vitro assays indicated that Shh (normally expressed in the MEE) activates Bmp2 expression in the palatal mesenchyme which in turn acts as a mitogen to stimulate cell division. Msx1 thus controls a genetic hierarchy involving BMP and Shh signals that regulates the growth of the anterior region of palate during mammalian palatogenesis. Our findings provide insights into the cellular and molecular etiology of the non-syndromic clefting associated with Msx1 mutations.

Reduction in the incidence of alveolar osteitis in patients treated with the SaliCept Patch, containing Acemannan Hydrogel

Purpose: In the present study, we compared the incidence of alveolar osteitis (AO) in patients treated with either clindamycin-soaked Gelfoam (Pharmacia and Upjohn Co, Kalamazoo, MI) or SaliCept Patches (Carrington Laboratories, Inc, Irving, TX). The SaliCept Patch is a freeze-dried pledget that contains Acemannan Hydrogel (Carrington Laboratories) obtained from the clear inner gel of Aloe vera L. Patients and Methods: A retrospective evaluation was performed of the records of 587 patients (1,031 sockets) whose extraction sites had been treated with clindamycin-soaked Gelfoam. A prospective trial was conducted in which 607 patients (1,064 sockets) had 2 SaliCept Patches placed immediately after extraction. The same surgeon treated all patients. Results: Analysis restricted to mandibular third molar sites showed that 78 of 975 sites (8.0%) in the Gelfoam group developed AO, whereas only 11 of 958 sites (1.1%) in the SaliCept group developed AO (P <.0001). Further analysis of all extraction sites revealed that the incidence of AO in the Gelfoam group was 7.6% compared with 1.1% in the SaliCept-treated group (P <.0001). Conclusions: The study results suggest that the SaliCept Patch significantly reduces the incidence of AO compared with clindamycin-soaked Gelfoam. © 2002 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 60:374-379, 2002

Changes in Lactate and Other Ions in Plaque and Saliva after a Fluoride Rinse and Subsequent Sucrose Administration

The purpose of this study was to examine plaque and saliva composition after a fluoride rinse and subsequent sucrose application. Fifteen subjects accumulated plaque for 48 h, and then rinsed with a fluoride rinse based on 228 µg/g (ppm) Na₂SiF₆ and some received no rinse. After 60 min, upper and lower buccal molar plaque samples and 1-min saliva samples were collected. The subjects then rinsed with 10% g/g sucrose solution, and 7 and 15 min later, a second and a third set of samples were collected. Plaque fluid and clarified saliva were then recovered from these samples by centrifugation, and the remaining plaque acid extracted. The plaque fluid, centrifuged saliva, and plaque extract samples were then analyzed using micro techniques for pH, free calcium, phosphate, organic acids (plaque fluid and saliva only) and fluoride. Considering both the fluoride rinse and no-rinse groups, the most notable compositional changes in saliva 7 min after the sucrose rinse were pH –0.40 unit, free calcium 0.42 mM, lactate 5.2 mM, phosphate –1.3 mM, and fluoride 2.8 µM; while in plaque fluid, the corresponding changes were pH –1.59 unit, free calcium 1.5 mM, lactate 35 mM, phosphate –1.6 mM and fluoride –26 µM. After sucrose rinsing, undersaturation was found with respect to dicalcium phosphate dihydrate in saliva and plaque fluid and with respect to tooth enamel in some plaque fluid samples. Plaque fluid composition appeared to be strongly influenced by salivary clearance, diffusive loss of ions into the water phase of the rinse, and lower jaw pooling of the sucrose and fluoride components of the rinses. After the experimental rinse, the fluoride concentration in plaque fluid [86 ± 22 mM (upper molar site), 162 ± 150 mM (lower molar site)], saliva (26 ± 18 mM), and whole plaque [99 ± 97 µg/g (upper molar site), 197 ± 412 µg/g (lower molar site)] was comparable to the values in previous studies using this rinse. These very high plaque fluid fluoride concentrations, compared with the ‘no-rinse’ samples, induced an approximately 0.3-unit increase in the plaque fluid pH 7 min after the sucrose rinse, a small decrease (approximately 20%) in lactate production and a modest increase in enamel saturation. Although these changes were all statistically significant, no correlation was found between the decrease in lactate concentration and plaque fluid fluoride, pH or whole plaque fluoride.

GCF IL-1beta profiles in periodontal disease.

Studies suggest a genetic influence on levels of interleukin-1beta (IL-1beta) in gingival crevicular fluid (GCF). Levels of IL-1beta in GCF, however, are also dependent upon the clinical parameters at the site of collection, including probing depth (PD) and level of attachment (AL). To examine this issue, IL-1beta in GCF was evaluated from patients with varying degrees of periodontal disease. The influence of both the status of the patient and the probing depth at the sampled sites were considered in the analysis. GCF IL-1beta was determined by ELISA at 6-8 molar sites from 29 non-smoking adults with mild, moderate, or severe periodontal disease at baseline, 2 weeks, and 24 weeks following scaling and root planing. For later analysis, patients were dichotomized on the basis of disease severity (mild/moderate vs severe). Sampled sites were classified at baseline by PD as, shallow (<4 mm), intermediate (4-6 mm), or deep (>6 mm). PD and AL were each strongly correlated with IL-1beta levels at baseline. However, patients with severe disease had higher levels of IL-1beta in each PD category than those with mild/moderate disease. As compared to patients with mild/moderate disease, IL-1beta levels in shallow sites from patients with severe disease was elevated nearly 2 fold (p<0.001). IL-1beta levels were reduced in all groups at 2 weeks and were still significantly reduced in patients with mild/moderate disease at 24 weeks. At 24 weeks IL-1beta returned to near baseline levels in patients with severe disease. While PD and AL are each associated with increased GCF IL-1beta, patients with severe disease show higher IL-1beta GCF levels in shallow sites, suggesting that high GCF IL-1beta expression is in part a host trait, and not strictly a function of clinical parameters.

Periodontal bone loss in Chinese subjects with untreated early-onset and adult periodontitis: a cross-sectional study using digital scanning radiographic image analysis.

The purpose of this investigation was to evaluate the differences in radiographic alveolar bone loss (RABL) in Taiwanese subjects with early-onset periodontitis (EOP) and adult periodontitis (AP) using the digital scanning radiographic image analysis (DSRIA). A total of 4,262 teeth from 178 individuals (96 males and 82 females) were examined for RABL due to EOP and AP. The subjects with EOP and a comparison group with AP were identified from the Periodontal Clinic population (College of Dental Medicine, Kaohsiung Medical University). The following criteria were used to classify subjects with EOP and AP during the past 20 years. The RABL of teeth were calculated using a computer system equipped with Microstation 95 software, under 10 X magnification of the radiographs. Quantity assessment of RABL using the DSRIA showed that: (1) the means of RABL of maxillary and mandibular anterior teeth in the EOP group were significant greater than those in the AP group when the two sample t-test was used. (2) The greatest values of mean RABL of affected sites in the EOP group occurred most commonly in the first molars and mandibular incisors, whereas, in the AP group, the greatest values of mean RABL of affected sites occurred most commonly in the first and second molars. (3) Molars had the greatest mean RABL followed by incisors, premolars and canines. (4) The mean RABL increased with increasing age. We conclude that the features of naturally progressing alveolar bone loss at the molar and incisor sites in untreated subjects with the EOP and AP revealed that the mean RABL in the EOP group was faster and greater than that in the AP group.

Epidemiology of clinical attachment loss in adolescents.

Relatively little is known about the prevalence, severity, and determinants of clinical attachment loss among adolescents. A multi-stage random sampling procedure was used to obtain a sample of 9,203 high school students aged 12 to 21 years from the Province of Santiago, Chile. All but 41 students were examined for clinical attachment loss in 6 sites of first and second molars and incisors. The students were interviewed with respect to tooth brushing habits, smoking habits, dental visits, and diabetic status. Logistic regression analyses were used to assess the relative strength of the associations between age, gender, smoking, tooth brushing habits, dental attendance patterns, diabetic status, and governmental school support and the occurrence of clinical attachment loss. Overall, clinical attachment loss > or = 1 mm was seen in 69.2% of the students; > or = 2 mm in 16% of the students; and > or = 3 mm in 4.5%. The distribution of clinical attachment loss was markedly skewed, but followed a continuum of disease severity. Logistic regression analyses showed that attachment loss was associated with higher age, female gender, infrequent tooth brushing, infrequent dental visits, and attending a high school receiving governmental support. No sharp distinction exists between periodontal health and disease among Chilean adolescents. Higher age, poor oral hygiene, and a lower socioeconomic background play a role in the occurrence of clinical attachment loss.

PMN responses following use of 2 biodegradable GTR membranes

AbstractObjectives: In the present prospective trial, the PMN response following resorbable GTR barrier placement was evaluated in mandibular class II furcation lesions.Materials and Methods: In 10 patients with treated chronic periodontitis, we randomly selected the 1st molars in the mandible with buccal degree II furcation involvement for either polylactic‐citric‐acid‐ester (PLA) or glycolide‐lactic‐copolymer (PGL) GTR membrane therapy. We examined contralateral healthy molar sites as untreated controls. We then evaluated the PMN‐derived inflammatory tissue response at baseline, weekly up to 6 weeks post‐therapy and at 12 and 24 weeks using GCF myeloperoxidase (MPO), beta‐glucuronidase (βG) and beta‐N‐acetyl‐hexosaminidase (βNAH).Results: The enzyme levels increased from baseline to the 6‐week examination. After the 6‐week reappointment, enzyme levels dropped reaching the baseline scores at both the 12‐ and 24‐week visit. At PGL sites, the enzyme levels decreased earlier. Compared with healthy control sites, the MPO, βNAH and βG tests revealed different maximum levels at week 2 and 3 (PGL) and week 4, 5 and 6 (PLA). For both of the barriers the clinical parameters revealed a sustained improvement following therapy.Conclusion: The release of PMN enzymes following placement of bioabsorbable membranes reflects the early soft tissue healing process. Our results suggest that the PMN response is barrier‐dependent with the maximum response occuring at different times. However, the host response did not measureably affect the course of clinical healing.

Effect of a Water Rinse on ‘Labile’ Fluoride and Other Ions in Plaque and Saliva before and after Conventional and Experimental Fluoride Rinses

Labile reservoirs are important in maintaining ion concentrations in oral fluids, especially after a fluoride dentifrice application, where a persistent increase in fluid fluoride can mitigate or reverse caries progression. In this study, the effect of experimental and conventional fluoride rinses on the in vitro and in vivo water–induced release of fluoride, calcium, phosphate, acetate and hydrogen ions from oral reservoirs was examined. At the start of each experiment, 13 subjects rinsed either with a conventional 228–ppm fluoride NaF rinse, a 228–ppm fluoride controlled–release rinse (CR rinse) or received no rinse. Sixty minutes later upper and lower molar plaque samples and 1–min saliva samples were collected. The subjects then rinsed with deionized water for 1 min, and 7 min later, a second set of samples was collected (in vivo study). Plaque fluid and clarified saliva were then recovered from samples by centrifugation, and the remaining plaque mass was sequentially extracted with water and acid to measure the water–extracted and total whole–plaque fluoride (in vitro study). All the samples were analyzed using microtechniques for pH, free calcium, phosphate, organic acids (plaque fluid) and fluoride (plaque fluid, centrifuged saliva and plaque extracts). Results showed that in vivo water rinsing decreased acetate and phosphate in plaque fluid, and fluoride in plaque fluid and saliva, but had no effect on plaque fluid pH. In vivo water rinsing, however, increased plaque fluid free calcium, apparently due to water–induced loss of calcium–binding ions. Water– or fluoride–rinse–induced changes in plaque fluid concentration were greater at the lower molar site, suggesting that rinse pooling may influence ion distribution. Before the water rinse, plaque fluid, saliva and whole–plaque total fluoride values were 1.7, 2 and 4 times higher after the CR rinse compared to the NaF rinse. Furthermore, the CR rinse deposited approximately 11 times more water–extracted fluoride compared to the NaF rinse, suggesting a ‘more efficient’ precipitation of ‘labile’ or ‘loosely bound fluoride’. The results presented here, and in previous studies, suggest the possibility of formulating effective fluoride dentifrices with a lower fluoride content than is currently in use.

The influence of margins of restorations on the periodontal tissues over 26 years

The purpose of this investigation was to examine the long-term relationship between dental restorations and periodontal health. The data derived from a 26-year longitudinal study of a group of Scandinavian middle-class males characterized by good to moderate oral hygiene and regular dental check-ups. At each of 7 examinations between 1969 and 1995, the mesial and buccal surfaces were scored for dental, restorative and periodontal parameters. The mesial sites of premolars and molars of 160 participants were observed during 26 years (1969-1995). A control group with 615 sound surfaces or filling margins located more than 1 mm from the gingival margin in all 7 surveys was compared with a test cohort with 98 surfaces which were sound or had filling margins located more than 1 mm from the gingival margin at baseline (1969) and had a subgingival filling margin 2 years after (1971). The study confirmed the long held concept that restorations placed below the gingival margin are detrimental to gingival and periodontal health. In addition, this study suggests that the increased loss of attachment found in teeth with subgingival restorations started slowly and could be detected clinically 1 to 3 years after the fabrication and placement of the restorations. A subsequent "burn-out" effect was suggested.

The influence of margins of restorations on the periodontal tissues over 26 years

AbstractAim: The purpose of this investigation was to examine the long‐term relationship between dental restorations and periodontal health.Material and Methods: The data derived from a 26‐year longitudinal study of a group of Scandinavian middle‐class males characterized by good to moderate oral hygiene and regular dental check‐ups. At each of 7 examinations between 1969 and 1995, the mesial and buccal surfaces were scored for dental, restorative and periodontal parameters. The mesial sites of premolars and molars of 160 participants were observed during 26 years (1969–1995). A control group with 615 sound surfaces or filling margins located more than 1 mm from the gingival margin in all 7 surveys was compared with a test cohort with 98 surfaces which were sound or had filling margins located more than 1 mm from the gingival margin at baseline (1969) and had a subgingival filling margin 2 years after (1971).Results and conclusions: The study confirmed the long held concept that restorations placed below the gingival margin are detrimental to gingival and periodontal health. In addition, this study suggests that the increased loss of attachment found in teeth with subgingival restorations started slowly and could be detected clinically 1 to 3 years after the fabrication and placement of the restorations. A subsequent “burn‐out” effect was suggested.

The bio-availability of fluoride from black tea

Objectives: To investigate the oral retention of fluoride from tea and its association with the tooth surface and acquired pellicle. Methods: Oral retention of fluoride after rinsing in vivo was assessed from expectorated samples with an ion specific electrode methodology. Interaction of fluoride with the tooth surface and acquired pellicle was examined in situ with enamel blocks mounted on partial removable appliances. In vitro models were used to examine fluoride binding to enamel particles. Results: Thirty four percent of the fluoride was retained in the oral cavity after rinsing with tea. Differences in retention at the tooth surface in the presence and absence of an acquired pellicle were not statistically significant at incisor or molar sites. Fluoride from tea showed strong binding to enamel particles, which was only partially dissociated by solutions of ionic strength considerably greater than that of saliva. Binding studies demonstrated strong avidity of enamel for tea and salivary pellicle components. Conclusions: This study has demonstrated that tea can provide an effective vehicle for fluoride delivery to the oral cavity where it may interact with the oral tissues and their surface integuments. This may lead to local topical effects of the ingested fluoride as well as systemic effects following oral and gastro-intestinal absorption.

Fluoride in Plaque Fluid, Plaque, and Saliva Measured for 2 hours after a Sodium Fluoride Monofluorophosphate Rinse

Sodium monofluorophosphate (NaMFP) and sodium fluoride (NaF) are the two most common sources of fluoride used in currently marketed fluoride dentifrices. The purpose of this study was to investigate the effect of mouth rinses containing NaF or NaMFP on the concentrations of fluoride, or the MFP ion, in saliva, whole plaque, and plaque fluid. Twelve subjects abstained from tooth brushing for 48 h, fasted overnight, and then rinsed 1 min with 12 mmol/l (228 ppm [μg/g] F) NaF or NaMFP in the morning. Before the rinse and at 30, 60 and 120 min afterwards, upper and lower molar and premolar plaque samples and whole saliva samples were collected. Aliquots of plaque fluid and centrifuged saliva were obtained from these samples, and the whole plaque residue acid extracted. The F and MFP concentrations were then measured in these samples using ultramicro methods. For both rinses, a higher concentration of plaque fluid fluoride was found at lower molar sites while the reverse was true for the whole plaque fluoride. Furthermore, for both rinses, plaque fluid, whole plaque, but not salivary, fluoride concentrations were above baseline at 120 min. Following the NaMFP rinse, a substantial amount of unhydrolyzed MFP was found in plaque fluid and saliva. Although there was a very large range in these measurements, fluoride in plaque fluid (excluding fluoride in unhydrolyzed MFP) and whole plaque were significantly (p<0.05) greater after the NaF rinse at all time periods. In saliva, the NaF rinse produced a statistically significant greater salivary fluoride (excluding fluoride in unhydrolyzed MFP) only at 60 min. The lack of a clear correlation between these measurements and clinical studies suggest a novel mechanism may enhance the effectiveness of NaMFP dentifrices.

Profile of subgingival microbiota in children with primary dentition.

Eruption of primary teeth has a great influence on the oral environment by providing suitable niches for bacterial colonization. The aim of the study was to investigate the composition of the subgingival microbiota of primary incisors, canines and molars in 40 systemically healthy children aged 4-5 yr, chosen randomly. Subgingival plaque samples were taken from the mesiobuccal sites of primary incisors (61, 81), canines (53, 73) and molars (64, 84). The samples were cultured for bacterial isolation anaerobically and in 10% CO2 plus air using selective and non-selective media. Forty-one different microbial species were isolated. Gemella morbillorum and Peptostreptococcus magnus were statistically significantly more frequently detected in incisors while P. micros, Streptococcus intermedius, Bacteroides forsythus, Fusobacterium nucleatum, Prevotella loeschei, P. melaninogenica and Selenomonas sputigena were more frequently detected in molars. The bacterial species S. constellatus, G. morbillorum and P. magnus were isolated in greater numbers in incisors and P. micros, S. intermedius, Campylobacter concisus, Bacteroides egertheii, B. forsythus, P. oralis and S. sputigena were isolated in greater numbers in molars, respectively. Cluster analysis revealed 4 clusters in which 6-7 bacterial species were elevated above mean levels. Cluster I was predominated by S. constellatus, S. mitis, S. sanguis, G. morbillorum, P. melaninogenica and P. oralis; cluster II was predominated by S. sanguis, Actinomyces naeslundii, Capnocytophaga gingivalis, C. ochracea and P. intermedia; cluster III was predominated by S. mitis, C. ochracea, F. nucleatum, P. loeschei, P. melaninogenica and P. oralis; and finally cluster IV was predominated by S. sanguis, C. gingivalis, Veillonella parvula, Campylobacter gracilis, F. nucleatum and P. intermedia. The bacterial species S. constellatus, P. micros, Pseudoramibacter alactolyticus, Eikenella corrodens and F. nucleatum were associated with non-bleeding sites while S. intermedius, C. concisus, P. intermedia and P. loescheii were found more frequently in bleeding sites.