Quantitative determination of lysophosphatidic acids (LPAs) in human saliva and gingival crevicular fluid (GCF) by LC-MS/MS

Lysophosphatidic acid (LPA) is a phospholipid mediator that plays multiple cellular functions by acting through G protein-coupled LPA receptors. LPAs are known to be key mediators in inflammation, and several lines of evidence suggest a role for LPAs in inflammatory periodontal diseases. A simple and sensitive liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method has been developed and validated to quantify LPA species (LPA 18:0, LPA 16:0, LPA 18:1 and LPA 20:4) in human saliva and gingival crevicular fluid (GCF). LPA 17:0 was used as an internal standard and the LPA species were extracted from saliva by liquid-liquid extraction using butanol. Chromatography was performed using a Macherey-Nagel NUCLEODUR® C8 Gravity Column (125 mm × 2.0 mm ID) with a mixture of methanol/water: 75/25 (v/v) containing 0.5% formic acid and 5 mM ammonium formate (mobile phase A) and methanol/water: 99/0.5 (v/v) containing 0.5% formic acid and 5mM ammonium formate (mobile phase B) at a flow rate of 0.5 mL/min. LPAs were detected by a linear ion trap-triple quadrupole mass spectrometer with a total run time of 8.5 min. The limit of quantification (LOQ) in saliva was 1 ng/mL for all LPA species and the method was validated over the range of 1-200 ng/mL. The method was validated in GCF over the ranges of 10-500 ng/mL for LPA 18:0 and LPA 16:0, and 5-500 ng/mL for LPA 18:1 and LPA 20:4. This sensitive LC-MS/MS assay was successfully applied to obtain quantitative data of individual LPA levels from control subjects and patients with various periodontal diseases. All four LPA species were consistently elevated in samples obtained from periodontal diseases, which supports a role of LPAs in the pathogenesis of periodontal diseases.

Compliance as a prognostic indicator. II. Impact of patient's compliance to the individual tooth survival

BACKGROUND

Existing evidence concerning the validity of an appropriate regular periodontal maintenance (PM) regimen and the role of patient compliance is controversial and inconsistent. The objectives of this study are to identify the impact of patient compliance (complete versus erratic) on alveolar bone loss and tooth survival.

METHODS

A retrospective study was conducted using data from 295 patients with >or=20 years of observation, which included treatment and >or=15 years of maintenance therapy, in a private practice in Yamagata, Japan. Subject-level variables and tooth-level variables were recorded at the initial visit, the reevaluation visit, and the final visit. In total, 7,502 teeth in 295 subjects met inclusion criteria and were divided into two groups: non-molar teeth (n = 5,585) and molar teeth (n = 1,917). A tooth-level multivariate survival model and multiple logistic regression model using the method of generalized estimating equations were constructed to analyze the effects of compliance and periodontal maintenance intervals on tooth loss and alveolar bone loss, respectively.

RESULTS

Of 7,502 teeth, 284 molar teeth and 364 non-molar teeth were lost. Molar teeth had an approximately 30% reduction in risk of tooth loss for complete compliance, with 2-year compliance classification achieving statistical significance (P = 0.033), and 30% compliance classification approaching statistical significance (P = 0.072). Complete compliers under 30% compliance classification showed over 50% reduction in the risk of alveolar bone loss among non-molars (P = 0.015).

CONCLUSION

Complete patient compliance with increased frequency of periodontal maintenance is important for improved dental prognosis through reduction of tooth loss among molars and minimization of alveolar bone loss among non-molars.

Snacking habits and caries in young children

Dental caries is caused by a combination of infection and diet. This disease, if left untreated, may lead to pain, and impair the quality of life, nutritional status and development of young children. The objective was to investigate the association between snacking and caries in a population at high risk of dental caries. American preschool children (n = 1,206) were recruited in the offices of paediatricians. Data on sociodemographic characteristics, oral hygiene, breast-feeding, use of bottle and snacking were collected by questionnaire. Plaque presence, the number of teeth and their caries status (deft) were scored. The children sampled were 61% Black, 27% White and 10% Asian. Of the 1- to 2-, 2- to 3- and 3- to 4-year-old children, 93.8, 82.4 and 77.3% were caries free, and their mean caries scores were 0.16, 0.58 and 0.93, respectively. Multivariate partial least squares (PLS) modelling revealed plaque presence, lowest income, descriptors for tooth exposure time (number of teeth and age) and cariogenic challenge (total intake of sugar-containing snacks and chips/crisps, and chips intake with a sugar-containing drink) to be associated with more caries. These differences were also found in univariate analyses; in addition, children who continued breast-feeding after falling asleep had significantly higher deft values than those who did not. PLS modelling revealed that eating chips clustered with eating many sweet snacks, candies, popcorn and ice cream. We conclude that, in addition to the traditional risk indicators for caries - presence of plaque, sugar intake and socioeconomic status -, consumption of chips was associated with caries in young children.

Oral microbiota of children in a school-based dental clinic

OBJECTIVES

Dental caries disproportionately affects disadvantaged subjects. This study hypothesized that there were greater caries extent and higher levels of caries-associated and anaerobic subgingival bacterial species in oral samples of Hispanic and immigrant children compared with non-Hispanic and US born children.

METHODS

Children from a school-based dental clinic serving a community with a large Hispanic component were examined, and the extent of caries was recorded. Microbial samples were taken from teeth and the tongues of children. Samples were analyzed using DNA probes to 18 oral bacterial species.

RESULTS

Seventy five children were examined. Extent of caries increased with child age in immigrant, but not in US born or Hispanic children. There were no differences in the microbiota based on ethnicity or whether the child was born in US or not. There was a higher species detection frequency from teeth than tongue samples. Levels of Streptococcus mutans and other Streptococcus spp increased with caries extent. Prevotella intermedia, Tannerella forsythia and Selenomonas spp were detected at low levels in these children.

CONCLUSIONS

We conclude that, while there was a high rate of dental caries in disadvantaged school children, there were no differences in the caries-associated microbiota, including S. mutans, based on ethnicity or immigration status. Furthermore, while anaerobic subgingival, periodontal pathogens were also detected in children, there was no difference in species detection based on ethnicity or immigration status. Increased levels of streptococci, including S. mutans, however, were detected with high caries levels. This suggested that while it is beneficial to target preventive and treatment programs to disadvantaged populations, there is likely no additional benefit to focus on subgroups within a population already at high risk for dental disease.

Microbial risk markers for childhood caries in pediatricians' offices

Dental caries in pre-school children has significant public health and health disparity implications. To determine microbial risk markers for this infection, this study aimed to compare the microbiota of children with early childhood caries with that of caries-free children. Plaque samples from incisors, molars, and the tongue from 195 children attending pediatricians' offices were assayed by 74 DNA probes and by PCR to Streptococcus mutans. Caries-associated factors included visible plaque, child age, race, and snacking habits. Species were detected more frequently from tooth than tongue samples. Lactobacillus gasseri (p < 0.01), Lactobacillus fermentum, Lactobacillus vaginalis, and S. mutans with Streptococcus sobrinus (all p < 0.05) were positively associated with caries. By multifactorial analysis, the probiotic Lactobacillus acidophilus was negatively associated with caries. Prevotella nigrescens was the only species (p < 0.05) significantly associated with caries by the 'false discovery' rate. Analysis of the data suggests that selected Lactobacillus species, in addition to mutans streptococci, are risk markers for early childhood caries.

Prevalence of early childhood caries among very young urban Boston children compared with US children

OBJECTIVES

The aims of this study were to compare prevalence of early childhood caries (ECC) in 1- to 3-year-old children seeing primary-care pediatricians at two urban medical centers in Boston to the prevalence of ECC in similarly aged US children surveyed as part of the Third National Health and Nutrition Examination Survey (NHANES III) and to assess risk factors for ECC among this cohort of children compared with risk factors among similarly aged US children.

METHODS

Characteristics of 787 1- to 3-year-old children from two urban Boston medical centers were compared with those of 3,644 similarly aged US children surveyed as part of NHANES III. Demographic and social characteristics and ECC prevalence by putative risk factors were compared. A multiple logistic regression model was fit to assess putative risk factors and difference between groups simultaneously.

RESULTS

Race, age, previous dental visit, parents' education, and household income were significantly associated with ECC prevalence. Parents' place of birth was a significant effect modifier with lower ECC among Boston children of immigrants than among US children of immigrants.

CONCLUSIONS

Lower ECC prevalence among urban Boston children of immigrant parents compared with US children of immigrant parents may reflect changing immigrant composition in the United States since NHANES III or a different immigrant composition in the Boston area compared with the United States. This finding reinforces the need for further research of immigrants in order to understand cultural practices that may affect oral health. Finally, low ECC prevalence among very young children reinforces the importance of early intervention in reducing ECC.

Healthy eating index is a predictor of early childhood caries

Early childhood caries (ECC) is a preventable form of dental caries that affects very young children, particularly among low-income families and certain racial/ethnic minorities. The current study examined the relationship of dietary quality, as measured by the Healthy Eating Index (HEI), to the prevalence of ECC in 2- to 5-year-old children. Data from the Third National Health and Nutrition Examination Survey (NHANES III) were used for the study. We used logistic regression to compute adjusted odds ratios (OR) for ECC and 95% confidence intervals (CI). Children with the best dietary practices (uppermost tertile of the HEI) were 44% less likely to exhibit severe ECC compared with children with the worst dietary practices (lowest tertile of the HEI). A healthy eating pattern geared for promotion of optimal child development and prevention of chronic disease in later life may also reduce the risk of early childhood caries, particularly severe early childhood caries.

A pilot study to evaluate a tissue-engineered bilayered cell therapy as an alternative to tissue from the palate

BACKGROUND

This study evaluated the safety and effectiveness of a tissue-engineered skin product composed of viable neonatal keratinocytes and fibroblasts and compared it to a free gingival graft (FGG) in a procedure to enhance keratinized tissue (KT) and wound healing around teeth that do not require root coverage.

METHODS

Twenty-five subjects were enrolled who had at least two non-adjacent teeth in contralateral quadrants exhibiting an insufficient zone of attached gingiva requiring soft tissue grafting where root coverage was not desired. One tooth was randomized to receive an FGG, and the other was randomized to receive bilayered cell therapy (BCT). The amount of KT was measured at baseline and 3 and 6 months, and the texture and color of the grafted tissue were compared to the surrounding tissue at months 1, 3, and 6. A questionnaire was used to determine subject preference at 6 months. Biopsies and persistence studies were performed on a subset of the subjects.

RESULTS

The FGG generated statistically significantly (P <0.001) more KT than the test device (BCT) (4.5 +/- 0.80 mm versus 2.4 +/- 1.02 mm); no significant difference in recession or clinical attachment level was detected between treatment groups (P = 0.212 and P = 0.448, respectively); and no significant differences were detected at any time point for bleeding on probing (BOP), resistance to muscle pull, or inflammation. The BCT group had significantly better color and texture match with surrounding tissue (P <0.001), and subject preference was significantly greater for the BCT group (P = 0.041). No device-related adverse events or safety issues occurred during the course of the study.

CONCLUSIONS

The tissue-engineered graft BCT was safe and capable of generating de novo KT without the morbidity and potential clinical difficulties associated with donor-site surgery. The amount of KT generated with FGG was greater than generated with BCT; however, 24 of 25 test sites demonstrated an increase in KT at 6 months, with more than three-quarters of the sites yielding > or =2 mm bands of KT.

Efficacy of a new papilla generation technique in implant dentistry: a preliminary study

PURPOSE

To compare the efficacy of a new uncovering technique with that of the conventional uncovering technique for papilla generation.

MATERIALS AND METHODS

Thirty-three patients with 67 implants were enrolled in the study. Patients were randomly assigned to 1 of 2 treatment groups (test and control). Implants of the test group were uncovered by the new technique and implants of the other group uncovered by the conventional technique (simple midcrestal incision). The height of each papilla after uncovering at baseline, 3 months, and 6 months and the thickness of the tissue covering the implant prior the uncovering were measured. PPD, PI, GI, and BOP measurements were made at 0 and 6 months, and standardized radiographs were obtained at 0, 3, and 6 months. Subject means were used for all statistical analyses.

RESULTS

The mean difference between the 2 surgical methods revealed that the new technique provided 1.5 mm greater papilla height (P < .001) at all 3 visits (baseline, 3, and 6 months) for implants adjacent to teeth. An overall significant difference for papilla height between the implants was detected between the 2 groups (P = .02). There was no significant difference between the 2 groups with regard to PPD, PI, GI, BOP, thickness of soft tissue, or overall bone level measurements during the course of the study.

CONCLUSION

Based on this study, it appears that over the course of 6 months, the new surgical approach for uncovering leads to a more favorable soft tissue response.

Salivary lysozyme and prevalent hypertension

Although the etiology of essential hypertension is not clearly understood, endothelial dysfunction from chronic infection and/or impaired glucose metabolism may be involved. We hypothesized that salivary lysozyme, a marker for oral infection and hyperglycemia, might display a significant relationship with hypertension, an early stage of cardiovascular disease. Logistic regression analyses of the Kuopio Oral Health and Heart Study demonstrated that persons with higher lysozyme levels were more likely to have hypertension, after adjustment for age, gender, smoking, BMI, diabetes, the ratio of total cholesterol to HDL cholesterol, and C-reactive protein. The exposure to increasing quartiles of lysozyme was associated with adjusted Odds Ratios for the outcome, hypertension, 1.00 (referent), 1.25, 1.42, and 2.56 (linear trend p < 0.003). When we restricted the sample to the individuals without heart disease (N = 250), we observed a non-significant trend for increasing odds. Our hypothesis--"high salivary lysozyme levels are associated with the odds of hypertension"--was confirmed.

Clinical Evaluation of the Supraosseous Gingivae Before and After Crown Lengthening

BACKGROUND

Despite the broad use of crown-lengthening surgery (CLS), there is no complete agreement as to the desired amount of exposed sound tooth structure needed to accommodate both the restorative needs and the reformation of the supraosseous gingiva (SOG). Classically, it has been proposed that approximately 3 mm of SOG, the amount considered by most to be present before surgery, will be reformed after CLS. The purpose of this study was to test the viability of transsulcular probing (TSP) and to determine whether the SOG that forms after CLS is the same as that measured preoperatively.

METHODS

Nineteen patients underwent CLS with the surgical tooth acting both as the control and the test site. The SOG dimension was measured by TSP before and 6 months after surgery. Stents were used as fixed reference points. Intraclass correlations were calculated to test for the reliability of TSP measurements versus direct-bone-level (DBL) measurements. A Wilcoxon signed-rank test was used to compare the means for the mean buccal, mean lingual, and overall mean SOG dimensions at baseline to corresponding measurements at 6 months.

RESULTS

Intraclass correlation coefficients for TSP measures of SOG to DBL measures of SOG ranged from 83.4% agreement to 91.9% agreement, with all correlations being highly significant (P <0.001), indicating a high degree of agreement between TSP and DBL. The differences in SOG dimensions, 6 months after surgery compared to baseline, were as follows: mean buccal, 0.51 mm; mean lingual/palatal, 0.61 mm; overall mean, 0.56 mm. These differences were significant for all three comparisons (P <0.001, P <0.004, and P <0.001, respectively).

CONCLUSIONS

TSP is an accurate alternative method to DBL in clinically determining SOG dimensions. Six months after CLS, the SOG dimension was reduced by 0.51 to 0.61 mm compared to the presurgical measurement, with these mean differences being statistically significant.

Treatment history of teeth in relation to the longevity of the teeth and their restorations: Outcomes of teeth treated and maintained for 15 years

STATEMENT OF PROBLEM

Limited clinical data exist on the survival of teeth relative to their treatment history.

PURPOSE

This study evaluated failure of teeth relative to their treatment history.

MATERIAL AND METHODS

Longitudinal data were collected for 3071 teeth from 148 fully compliant patients from 1 private practice in Yamagata, Japan. Follow-up times ranged from 15 to 23 years, with a mean of 19.2 years (SD 2.4). In this study, every tooth and its restoration were evaluated by one of the authors at the time of each maintenance visit. Treatment history of the teeth was categorized at baseline as follows: (1) sound, unrestored tooth (SUT); (2) 1-surface restoration (RT1); (3) 2-surface restoration (RT2); (4) 3-surface restoration (RT3); (5) 4+-surface restoration (RT4); (6) complete crown (CCT); (7) abutment for fixed partial dental prosthesis (AFT); (8) abutment for removable partial dental prosthesis (APDT); and (9) root canal treatment (RCT). Three types of failure modes were evaluated in this study: (1) restorative failure (secondary caries and/or fracture), (2) extraction, and (3) any failure (restorative failure or extraction). Multivariate survival analysis was used to determine the impact of the treatment history on failure (alpha=.05).

RESULTS

Teeth with multi-surface restorations experienced the highest incidence of any failure (P<.001). For secondary caries, similar risks were noted for the different treatment histories. For failures resulting in extraction, the only teeth with an increased risk were abutments for removable partial dental prostheses (relative risk=5.5) (P=.008).

CONCLUSIONS

The data demonstrated that restored teeth experienced a higher incidence of failure compared with unrestored teeth. Complete crowns and abutments for fixed partial dental prostheses had fewer restorative failures when compared with teeth with complex multisurface restorations. Removable partial denture abutments experienced the highest failure rate.

A Comparative Study of Root Coverage Using Acellular Dermal Matrix With and Without Enamel Matrix Derivative

BACKGROUND

The aim of this study was to compare root coverage using acellular dermal matrix (ADM) with and without enamel matrix derivative (EMD) on the percentage of root coverage, probing attachment level, and the amount of keratinized tissue in the treatment of localized recession.

METHODS

Eighty-two contralateral sites in 14 patients with >or=2 mm of Miller Class I or III buccal tissue recession were treated. Forty-one test sites were treated with coronally advanced flap (CAF) using ADM in conjunction with EMD, whereas 41 control sites were treated with CAF using ADM alone. A split-mouth design was used for this study with 82 sites. Patients were followed for 3 and 6 months. A paired t test was conducted with the subject as the unit of analysis.

RESULTS

Based on paired t tests, both groups had significant improvement in the percentage of root coverage, probing attachment levels, and increased keratinized tissue. Only keratinized tissue in the test group demonstrated a statistically significant greater increase compared to controls at the 6-month evaluation (P = 0.006).

CONCLUSION

The use of EMD in conjunction with ADM resulted in a statistically significant effect on keratinized tissue increase, but no significant effects on probing attachment level or percentage of root surface coverage.

Gingivitis susceptibility and its relation to periodontitis in men

The objective of this cross-sectional study was to evaluate whether gingivitis susceptibility is associated with periodontitis. We analyzed data of 462 men in the VA Dental Longitudinal Study aged 47 to 92 years who had never smoked or had quit smoking 5+ years previously. Multiple logistic regression models, with tooth-level bleeding on probing at sites with attachment loss<or=2 mm as the dependent variable, were derived with adjustment for plaque, calculus, crown coverage, age, income, education, marital status, body mass index, diabetes, and vitamin C intake, and stratification by age (<65, 65+ years). Periodontitis and mean attachment loss were positively associated with bleeding on probing, with stronger associations among men<65 years old (for periodontitis, OR 2.1; 95% CI 1.5, 3.1) than men 65+ years of age (OR 1.2; 95% CI 0.9, 1.6). Our results suggest that among never and former smokers, gingivitis susceptibility is higher among men with periodontitis compared with that in men without periodontitis.

Cigarette smoking increases the risk of root canal treatment

Few studies have investigated smoking as a risk factor for root canal treatment. We studied the effect of smoking on the incidence of root canal treatment, controlling for recognized risk factors, in 811 dentate male participants in the VA Dental Longitudinal Study. Participants were not VA patients. Follow-up ranged from 2 to 28 years. Root canal treatment was verified on radiographs and evaluated with proportional hazards regression models. Compared with never-smokers, current cigarette smokers were 1.7 times as likely to have root canal treatment (p < 0.001), but cigar and/or pipe use was not significantly associated with root canal treatment. The risk among cigarette smokers increased with more years of exposure and decreased with length of abstinence. These findings suggest that there is a dose-response relationship between cigarette smoking and the risk of root canal treatment.