Affective value, intensity and quality of liquid tastants/food discernment in the human brain: An activation likelihood estimation meta-analysis.

The primary dimensions of taste are affective value, intensity and quality. Numerous studies have reported the role of the insula in evaluating these dimensions of taste; however, the results were inconsistent. Therefore, in the current study, we performed meta-analyses of published data to identify locations consistently activated across studies and evaluate whether different regions of the human brain could be responsible for processing different dimensions of taste. Meta-analyses were performed on 39 experiments, with 846 total healthy subjects (without psychiatric/neurological disorders) in 34 studies reporting whole-brain results. The aim was to establish the activation likelihood estimation (ALE) of taste-mediated regional activation across the whole brain. Apart from one meta-analysis for all studies in general, three analyses were performed to reveal the clusters of activation that were attributable to processing the affective value (data from 323 foci), intensity (data from 43 foci) and quality (data from 45 foci) of taste. The ALE revealed eight clusters of activation outside the insula for processing affective value, covering the middle and posterior cingulate, pre-/post-central gyrus, caudate and thalamus. The affective value had four clusters of activation (two in each hemisphere) in the insula. The intensity and quality activated only the insula, each with one cluster on the right. The concurrence between studies was moderate; at best, 53% of the experiments contributed to the significant clusters attributable to the affective value, 60% to intensity and 50% to quality. The affective value was processed bilaterally in the anterior to middle insula, whereas intensity was processed in the right antero-middle insula, and quality was processed in the right middle insula. The right middle dorsal insula was responsible for processing both the affective value and quality of taste. The exploratory analysis on taste quality did not have a significant result if the studies using liquid food stimuli were excluded. Results from the meta-analyses on studies involving the oral delivery of liquid tastants or liquid food stimuli confirmed that the insula is involved in processing all three dimensions of taste. More experimental studies are required to investigate whether brain activations differ between liquid tastants and food. The coordinates of activated brain areas and brain maps are provided to serve as references for future taste/food studies.

Multilocus Sequence Analysis of Phylogroup 1 and 2 Oral Treponeme Strains.

More than 75 "species-level" phylotypes of spirochete bacteria belonging to the genus Treponema reside within the human oral cavity. The majority of these oral treponeme phylotypes correspond to as-yet-uncultivated taxa or strains of uncertain standing in taxonomy. Here, we analyze phylogenetic and taxonomic relationships between oral treponeme strains using a multilocus sequence analysis (MLSA) scheme based on the highly conserved 16S rRNA, pyrH, recA, and flaA genes. We utilized this MLSA scheme to analyze genetic data from a curated collection of oral treponeme strains (n = 71) of diverse geographical origins. This comprises phylogroup 1 (n = 23) and phylogroup 2 (n = 48) treponeme strains, including all relevant American Type Culture Collection reference strains. The taxonomy of all strains was confirmed or inferred via the analysis of ca. 1,450-bp 16S rRNA gene sequences using a combination of bioinformatic and phylogenetic approaches. Taxonomic and phylogenetic relationships between the respective treponeme strains were further investigated by analyzing individual and concatenated flaA (1,074-nucleotide [nt]), recA (1,377-nt), and pyrH (696-nt) gene sequence data sets. Our data confirmed the species differentiation between Treponema denticola (n = 41) and Treponema putidum (n = 7) strains. Notably, our results clearly supported the differentiation of the 23 phylogroup 1 treponeme strains into five distinct "species-level" phylotypes. These respectively corresponded to "Treponema vincentii" (n = 11), Treponema medium (n = 1), "Treponema sinensis" (Treponema sp. IA; n = 4), Treponema sp. IB (n = 3), and Treponema sp. IC (n = 4). In conclusion, our MLSA-based approach can be used to effectively discriminate oral treponeme taxa, confirm taxonomic assignment, and enable the delineation of species boundaries with high confidence. IMPORTANCE: Periodontal diseases are caused by persistent polymicrobial biofilm infections of the gums and underlying tooth-supporting structures and have a complex and variable etiology. Although Treponema denticola is strongly associated with periodontal diseases, the etiological roles of other treponeme species/phylotypes are less well defined. This is due to a paucity of formal species descriptions and a poor understanding of genetic relationships between oral treponeme taxa. Our study directly addresses these issues. It represents one of the most comprehensive analyses of oral treponeme strains performed to date, including isolates from North America, Europe, and Asia. We envisage that our results will greatly facilitate future metagenomic efforts aimed at characterizing the clinical distributions of oral treponeme species/phylotypes, helping investigators to establish a more detailed understanding of their etiological roles in periodontal diseases and other infectious diseases. Our results are also directly relevant to various polymicrobial tissue infections in animals, which also involve treponeme populations.

Getting to the Root of Fine Motor Skill Performance in Dentistry: Brain Activity During Dental Tasks in a Virtual Reality Haptic Simulation.

BACKGROUND: There is little evidence considering the relationship between movement-specific reinvestment (a dimension of personality which refers to the propensity for individuals to consciously monitor and control their movements) and working memory during motor skill performance. Functional near-infrared spectroscopy (fNIRS) measuring oxyhemoglobin demands in the frontal cortex during performance of virtual reality (VR) psychomotor tasks can be used to examine this research gap. OBJECTIVE: The aim of this study was to determine the potential relationship between the propensity to reinvest and blood flow to the dorsolateral prefrontal cortices of the brain. A secondary aim was to determine the propensity to reinvest and performance during 2 dental tasks carried out using haptic VR simulators. METHODS: We used fNIRS to assess oxygen demands in 24 undergraduate dental students during 2 dental tasks (clinical, nonclinical) on a VR haptic simulator. We used the Movement-Specific Reinvestment Scale questionnaire to assess the students' propensity to reinvest. RESULTS: Students with a high propensity for movement-specific reinvestment displayed significantly greater oxyhemoglobin demands in an area associated with working memory during the nonclinical task (Spearman correlation, rs=.49, P=.03). CONCLUSIONS: This small-scale study suggests that neurophysiological differences are evident between high and low reinvesters during a dental VR task in terms of oxyhemoglobin demands in an area associated with working memory.

In-depth snapshot of the equine subgingival microbiome.

This study explored the range of bacterial taxa present within healthy subgingival (below the gum-line) niches in the horse oral cavity using 16S rRNA gene amplicon pyrosequencing. Pooled subgingival plaque samples were collected from approximately 200 sulcus sites from two horses (EQ1, EQ2) for analysis. A total of 14,260 quality-filtered pyrosequencing reads were obtained, which were assigned to 3875 operational taxonomic units (OTUs; 99% identity cut-off); 1907 OTUs for EQ1 and 2156 OTUs for EQ2. Diverse taxa from 12 phyla were identified, including Actinobacteria (3.17%), Bacteroidetes (25.11%), Chloroflexi (0.04%), Firmicutes (27.57%), Fusobacteria (5.15%), Proteobacteria (37.67%), Spirochaetes (0.15%), Synergistetes (0.22%), Tenericutes (0.16%), GN02 (0.19%), SR1 (0.01%) and TM7 (0.37%). Many OTUs were not closely related to known phylotypes, and may represent 'equine-specific' taxa. Phylotypes corresponding to Gammaproteobacteria were abundant, including Actinobacillus spp. (8.75%), unclassified Pasteurellaceae (9.90%) and Moraxella spp. (9.58%). PCR targeting the Synergistetes and Spirochaetes phyla was performed, and resultant plasmid libraries of 16S rRNA gene amplicons (ca. 1480 bp) were Sanger sequenced. Twenty-six Spirochaetes OTUs, and 16 Synergistetes OTUs were identified (99% identity cut-off). These 'species-level' OTUs were assigned Equine Oral Taxon (EOT) numbers, whose phylogenies and taxonomy were comprehensively investigated, in conjunction with corresponding Synergistetes and Spirochaetes OTUs identified by pyrosequencing. The vast majority of Spirochaetes taxa belonged to the genus Treponema, which corresponded to 7 of the 10 human oral treponeme phylogroups. Other Spirochaetes taxa belonging to the Leptospiraceae family were observed; but many treponemes commonly implicated in animal hoof/foot and non-oral soft tissue infections; e.g. Treponema phagedenis, Treponema pedis, Treponema refringens, Treponema calligyrum; were not identified here. Diverse Synergistetes taxa corresponding to oral clusters A and B were identified, which included Fretibacterium fastidiosum and Pyramidobacter piscolens. Taken together, our data reveals that equine subgingival plaque microbiota shares many similarities with the human, canine and feline oral microbiomes.

Distributions of Synergistetes in clinically-healthy and diseased periodontal and peri-implant niches.

Bacterial taxa belonging to the phylum Synergistetes are commonly detected within diseased periodontal niches, but are rarely found within healthy oral sites. However, as they typically constitute a minor fraction of the oral microbiota, their precise distributions and disease-associations remain to be fully established. Here, we surveyed the Synergistetes taxa present within individual periodontal/subgingival and peri-implant/submucosal sites, within Chinese subjects (n = 18) affected by both peri-implantitis and periodontitis. Four individual, clinically-distinct sites were analyzed in each patient: healthy sulcus; periodontitis lesion; healthy peri-implant space; peri-implantitis lesion. We employed a clone library-based approach, using PCR-primers that specifically amplified ca. 650bp regions of the 16S rRNA gene from oral cluster A and B Synergistetes taxa. Twenty-one of the 72 sites (from 12/18 subjects) yielded Synergistetes 16S rRNA PCR products. Sequencing of cloned amplicon libraries yielded 1338 quality-filtered 16S rRNA sequences, which were assigned to 26 Synergistetes operational taxonomic units (OTUs; oral taxon SH01-SH26) using a 98.5% identity cut-off. We identified 25 Synergistetes oral cluster A OTUs (genus Fretibacterium; corresponding to Human Oral Taxon (HOT) numbers 358, 359, 360, 361, 362, 363, 452, and 453), and one oral cluster B OTU (Pyramidobacter piscolens oral taxon SH04, HOT-357). Three OTUs predominated: Fretibacterium oral taxon SH01 (HOT-360), Fretibacterium oral taxon SH02 (HOT-452), and Fretibacterium fastidiosum oral taxon SH03 (HOT-363). The Synergistetes community compositions within the respective periodontal and peri-implant sites were variable and complex, and no statistically-significant correlations could be established. However, the detection frequency of F. fastidiosum SH03 and Fretibacterium oral taxon SH01 were both positively associated with plaque index at healthy subgingival sites. Taken together, our results show that diverse Synergistetes populations inhabit both diseased and healthy periodontal and peri-implant niches, with considerable site-to-site variations in composition occurring within the same oral cavity.

Perception of Non-surgical Periodontal Treatment in Individuals Receiving or Not Receiving Local Anaesthesia.

PURPOSE: Patients might refuse the offer of local anaesthesia (LA) administration prior to dental treatment. This study investigates subjective discomfort perception during non-surgical mechanical periodontal therapy delivered with or without LA. MATERIALS AND METHODS: Sixty patients with mild to moderate chronic periodontitis and prior periodontal debridement experience were randomly enrolled in nonsurgical therapy of a quadrant with or without LA administration. Patients were free to comply or not with the allocated LA arrangement. Visual analogue scales (VAS) of discomfort perception at various stages of the treatment as well as overall satisfaction were recorded. Demographic, psychosocial and periodontal parameters were recorded. RESULTS: Thirty-one patients undergoing nonsurgical periodontal therapy not receiving (LA-) and 29 participants receiving LA (LA+) were studied. Compared to LA- patients, LA+ individuals perceived less discomfort during treatment and reported less dental anxiety (p<0.05). Lower overall treatment satisfaction was associated with prior unpleasant periodontal experience (p=0.047). Overall, debridement discomfort was associated with not receiving LA, noncompliance with the pain control regimen allocated, longer treatment duration, greater gingival inflammation and a higher percentage sites with probing pocket depths≥5 mm (p<0.05). CONCLUSION: Clinicians should be aware that patients who refuse LA can experience higher dental anxiety and therefore may require various pain control strategies for comfort during nonsurgical periodontal therapy, which, if not employed, can lead to less periodontal treatment satisfaction.

Multilocus sequence analysis of Treponema denticola strains of diverse origin.

BACKGROUND: The oral spirochete bacterium Treponema denticola is associated with both the incidence and severity of periodontal disease. Although the biological or phenotypic properties of a significant number of T. denticola isolates have been reported in the literature, their genetic diversity or phylogeny has never been systematically investigated. Here, we describe a multilocus sequence analysis (MLSA) of 20 of the most highly studied reference strains and clinical isolates of T. denticola; which were originally isolated from subgingival plaque samples taken from subjects from China, Japan, the Netherlands, Canada and the USA. RESULTS: The sequences of the 16S ribosomal RNA gene, and 7 conserved protein-encoding genes (flaA, recA, pyrH, ppnK, dnaN, era and radC) were successfully determined for each strain. Sequence data was analyzed using a variety of bioinformatic and phylogenetic software tools. We found no evidence of positive selection or DNA recombination within the protein-encoding genes, where levels of intraspecific sequence polymorphism varied from 18.8% (flaA) to 8.9% (dnaN). Phylogenetic analysis of the concatenated protein-encoding gene sequence data (ca. 6,513 nucleotides for each strain) using Bayesian and maximum likelihood approaches indicated that the T. denticola strains were monophyletic, and formed 6 well-defined clades. All analyzed T. denticola strains appeared to have a genetic origin distinct from that of 'Treponema vincentii' or Treponema pallidum. No specific geographical relationships could be established; but several strains isolated from different continents appear to be closely related at the genetic level. CONCLUSIONS: Our analyses indicate that previous biological and biophysical investigations have predominantly focused on a subset of T. denticola strains with a relatively narrow range of genetic diversity. Our methodology and results establish a genetic framework for the discrimination and phylogenetic analysis of T. denticola isolates, which will greatly assist future biological and epidemiological investigations involving this putative 'periodontopathogen'.

Comparative analysis of oral treponemes associated with periodontal health and disease.

BACKGROUND: Periodontal diseases, such as periodontitis, are chronic inflammatory infections affecting the gingivae (gums), underlying connective tissues and bone that support the teeth. Oral treponemes (genus Treponema) are widely-considered to play important roles in periodontal disease etiology and pathogenesis; however, precise relationships remain to be fully established. METHODS: A 16S rRNA clone library-based approach was used to comprehensively characterize and compare the diversity of treponeme taxa present in subgingival plaque sampled from periodontitis patients (n = 10) versus periodontitis-free controls (n = 10). 16S rRNA gene sequences were assigned to operational taxonomic units (OTUs) using a 99% identity cut-off A variety of taxonomy (OTU) and phylogeny-based statistical approaches were used to compare populations of treponeme OTUs present in both subject groups. RESULTS: A total of 615 plasmid clones containing ca. 1500 bp Treponema 16S rRNA gene sequences were obtained; 365 from periodontitis subjects, 250 from periodontitis-free controls. These were assigned to 110 treponeme OTUs. 93 OTUs were detected in the periodontitis subjects (mean 9.3 ± 5.2 OTUs per subject; range 9-26), and 43 OTUs were detected in controls (mean 4.3 ± 5.9 OTUs per subject; range 3-20). OTUs belonging to oral treponeme phylogroups 1-7 were detected in both subject sets. Phylogroup 1 treponemes had the highest levels of OTU richness (diversity) and clonal abundance within both subject groups. Levels of OTU richness and clonal abundance of phylogroup 2 treponemes were significantly higher in the periodontitis subjects (Mann Whitney U-test, p < 0.001). Both OTU-based and phylogeny-based analyses clearly indicated that there were significant differences in the composition of treponeme communities present in periodontitis versus control subjects. The detection frequency of five OTUs showed a statistically-significant correlation with disease status. The OTU (8P47) that corresponded to the type strain of Treponema denticola had the strongest association with periodontitis (p < 0.01). CONCLUSIONS: Higher levels of treponeme taxon richness and clonal abundance were associated with periodontitis. However, our results clearly indicated that subjects free from clinical symptoms of periodontal disease also contained highly diverse populations of treponeme bacteria within their subgingival microbiota. Our data supports the hypothesis that specific treponeme taxa are associated with periodontal disease.

Survival of molar teeth after resective periodontal therapy--a retrospective study.

AIM: To study outcomes of molar teeth after resective therapy performed with the intention to prolong the lifespan of teeth having one or more unsaveable roots, and without which tooth extraction would be inevitable. MATERIAL AND METHODS: Clinical records of 149 subjects who had undergone resective therapy were retrieved. Demography and dental history were recorded, and a recall examination was undertaken. Cox regression models were performed. RESULTS: Of the 149 resective therapies, 132 (88.6%) were performed for periodontal reasons. Eighty-nine (59.7%) teeth subjected to resective therapies had been extracted by the time of recall (mean 10 years post-resection). The median survival period was 74 months. Factors significantly associated with shorter survival duration of teeth subjected to resective therapy were: age at resective therapy; pre-operative radiographic bone height of the remaining root(s) <50%; pre-treatment mobility II or above and not being splinted to neighbouring teeth nor incorporated as a bridge abutment. CONCLUSION: There was increased risk of tooth loss with increasing age at resection, grade II mobility or above, and reduced pre-operative radiographic bone heights around roots to remain. Splinting of a resected tooth to neighbouring teeth appeared to confer a protective effect towards its survival.

Oral health of Chinese people with systemic sclerosis.

The aim was to study oral health status, salivary function, and oral features of Chinese people with Systemic Sclerosis (SSc). Chinese people with SSc attending a university specialist clinic were invited for a questionnaire survey and a clinical examination. Ethics approval was sought (UW 08-305). Gender- and age-matched individuals without SSc who attended a university dental hospital were recruited for comparison. Forty-two SSc patients with a mean age of 54.0 ± 12.2 were examined. This study found no Chinese people with systemic sclerosis were periodontally healthy and many (76%) had periodontal pockets despite most of them (93%) practiced daily tooth-brushing. They all had caries experience (DMFT = 10.5) and many (65%) had untreated decay. Mucosal telangiectasia was a common oral feature (80%). They had lower resting salivary flow rates (0.18 ± 0.17 ml/min vs. 0.31 ± 0.21 ml/min; p = 0.003) and pH values (6.90 ± 0.40 vs. 7.28 ± 0.31; p < 0.001) and reduced maximal mouth opening (40.1 ± 6.5 mm vs. 43.6 ± 7.0 mm) than people without SSc.

A bibliometric study of the top cited papers related to periodontal regeneration.

This report identifies the top cited papers in the field of periodontal regeneration since inception of the concept. Using the H-classics approach, 132 papers published between 1970 and 2012 were identified, with 230.0 ± 175.6 (mean ± SD) citations and 10.4 ± 11.5 citations/year. There were 46 clinical reports, 28 animal studies, 23 in vitro studies, 30 reviews, 3 systematic reviews, and 2 combined animal and in vitro studies. Analysis of covariance showed that institution number (≥3, P = 0.011), journal impact factor at publication (>3.0, P = 0.001) and study type (in vitro/reviews vs. clinical trials/animal studies, P = 0.024) were significantly associated with citations/year. This study has characterized the most influential literature in the field of periodontal regeneration and serves as a quick reference resource.

Diversity of Treponema denticola and Other Oral Treponeme Lineages in Subjects with Periodontitis and Gingivitis.

More than 75 species/species-level phylotypes belonging to the genus Treponema inhabit the human oral cavity. Treponema denticola is commonly associated with periodontal disease, but the etiological roles and ecological distributions of other oral treponemes remain more obscure. Here, we compared the clinical distributions of phylogroup 1 and 2 oral treponemes in subgingival plaque sampled from Chinese subjects with periodontitis (n = 10) and gingivitis (n = 8) via sequence analysis of the highly conserved pyrH housekeeping gene. Two PCR primer sets that targeted oral phylogroup 1 and 2 treponeme pyrH genes were used to construct plasmid clone amplicon libraries for each subject, and the libraries were sequenced for bioinformatic analysis. A total of 1,204 quality-filtered, full-length pyrH gene sequences were obtained from the cohort (median number, 61.5 cloned pyrH sequences per subject; range, 59 to 83), which were assigned to 34 pyrH genotypes (designated pyrH001 to pyrH034; 97% sequence identity cutoff). Eighteen pyrH genotypes (536 pyrH sequences) corresponded to phylogroup 1 treponeme taxa (including Treponema vincentii and Treponema medium). Sixteen pyrH genotypes (668 pyrH sequences) corresponded to T. denticola and other phylogroup 2 treponemes. Samples from periodontitis subjects contained a greater diversity of phylogroup 2 pyrH genotypes than did samples from gingivitis subjects (Mann-Whitney U test). One T. denticola pyrH genotype (pyrH001) was highly prevalent, detected in 10/10 periodontitis and 6/8 gingivitis subjects. Several subjects harbored multiple T. denticola pyrH genotypes. Nonmetric multidimensional scaling and permutational multivariate analysis of variance (PERMANOVA) revealed no significant differences in overall pyrH genotype compositions between periodontitis and gingivitis subjects. Taken together, our results show that subjects with periodontitis and gingivitis commonly harbor highly taxonomically diverse communities of oral treponemes. IMPORTANCE Periodontal diseases, such as periodontitis, are highly complex, multifactorial inflammatory infectious diseases affecting the gums and tooth-supporting structures. They are caused by chronic accumulations of dental plaque below the gum line that typically comprise hundreds of different bacterial species. Certain species of spiral-shaped bacteria known as treponemes, most notably Treponema denticola, are proposed to play key roles in the development and progression of periodontal disease. In our study, we characterized the genetic lineages of T. denticola, Treponema vincentii, Treponema medium, and related species of treponeme bacteria that were present in dental plaque samples from Chinese subjects with periodontal disease. Our results revealed that individual subjects commonly harbored multiple genetic lineages (strains) of T. denticola and other species of treponeme bacteria. Taken together, our results indicate that highly diverse and complex populations of oral treponemes may be present in dental plaque, which may potentially play important roles affecting periodontal health status.

Analysing Complex Oral Protein Samples: Complete Workflow and Case Analysis of Salivary Pellicles.

Studies on small quantity, highly complex protein samples, such as salivary pellicle, have been enabled by recent major technological and analytical breakthroughs. Advances in mass spectrometry-based computational proteomics such as Multidimensional Protein Identification Technology have allowed precise identification and quantification of complex protein samples on a proteome-wide scale, which has enabled the determination of corresponding genes and cellular functions at the protein level. The latter was achieved via protein-protein interaction mapping with Gene Ontology annotation. In recent years, the application of these technologies has broken various barriers in small-quantity-complex-protein research such as salivary pellicle. This review provides a concise summary of contemporary proteomic techniques contributing to (1) increased complex protein (up to hundreds) identification using minute sample sizes (µg level), (2) precise protein quantification by advanced stable isotope labelling or label-free approaches and (3) the emerging concepts and techniques regarding computational integration, such as the Gene Ontology Consortium and protein-protein interaction mapping. The latter integrates the structural, genomic, and biological context of proteins and genes to predict protein interactions and functional connections in a given biological context. The same technological breakthroughs and computational integration concepts can also be applied to other low-volume oral protein complexes such as gingival crevicular or peri-implant sulcular fluids.

Expression and localization of cystic fibrosis transmembrane conductance regulator in human gingiva.

CFTR (cystic fibrosis transmembrane conductance regulator) is a cAMP-activated chloride channel that regulates electrolyte and water transport. The present study investigated the expression and localization of CFTR in human gingiva and explored the possible association of CFTR with periodontal conditions. CFTR expression in gingival biopsies from five periodontally healthy subjects and ten subjects with chronic periodontitis and in the RHGE (reconstituted human gingival epithelia) was detected by immunohistochemistry, whereas its expression in gingival biopsies was analysed by immunofluorescence staining. CFTR mRNA was analysed by reverse transcription-PCR. CFTR mRNA was detected in human gingival epithelia and RHGE. CFTR protein was detected in gingival biopsies from both healthy subjects and individuals with periodontitis and in RHGE. In healthy subjects, CFTR expression was mainly confined to the granular and spinous layers of epithelia and localized on the cell membrane. In patients with periodontitis, CFTR was detected in all layers of epithelia and the underlying connective tissues. The mean CFTR expression levels in periodontitis patients were significantly higher than those in healthy subjects. The present study for the first time showed the expression and localization of CFTR in human gingival epithelia. Elevated CFTR expression in periodontitis subjects implies the possible involvement of CFTR in periodontal disease pathogenesis. Further study is warranted to confirm the present findings.

Effects of smoking on healing response to non-surgical periodontal therapy: a multilevel modelling analysis.

AIM: To investigate the factors predicting non-surgical periodontal treatment responses using multilevel multiple regression. MATERIAL AND METHODS: Forty men (mean 45.6 years) were recruited; 20 were smokers. A 12-month reduction in probing pocket depth (PPD) and gain in probing attachment level (PAL) of 5814 sites were analysed, with 594 being initially diseased sites (initial PPD> or =5 mm). RESULTS: Variance Component models showed that site-level variations contributed about 70-90% of the total variance. About a 10% reduction of the total variations of PPD reduction in initially diseased sites was achieved with the inclusion of the 10 predictors in the multilevel multiple regression. Multilevel multiple regression showed that three predictors, subject level: non-smokers; tooth-level: anterior teeth; and site level: sites without plaque at baseline, were significantly associated with a greater reduction in PPD in initially diseased sites over the 12-month study period (p<0.05). No consistent predictor was found for PAL gain. CONCLUSION: Multilevel analysis was applied on periodontal treatment response data. Smokers showed less favourable PPD reduction at deep sites after non-surgical periodontal therapy.

Oral Health and Its Associated Factors Among Older Institutionalized Residents-A Systematic Review.

The oral health of an ageing population, especially that of the institutionalized elderly population, constitutes a significant concern because it is closely linked to general health and the quality of life. Shared common risk factors drive the development and worsening of poor oral health and non-communicable diseases, which eventually lead to self-care inability. Several studies have reported on the poor oral health of the institutionalized elderly population. However, few comprehensive reports exist regarding the relationship between poor oral health, the oral health-related quality of life (OHRQoL) and the associated factors in this specific population. Objective: The objective is to describe recently reported oral health levels, the OHRQoL and the associated factors among older institutional residents. Methods: Studies published between July 2009 and June 2019 in MEDLINE, EMBASE and CINAHL were searched. The population, intervention, comparison and outcome (PICO) strategy was used as a guide. The reported factors related to poor oral health were identified (i.e., age, gender, educational level, acquired systemic conditions or dementia/cognitive impairment). Results: Twenty-five surveys (or study series) from 19 countries were included. The level of evidence reported by these studies was generally moderate to strong. The reported oral cleanliness and health of the surveyed institutionalized elderly were poor (>50% of residents had calculus; denture hygiene index > 80%). Gum (approximately 30% of dentate residents had moderate to severe periodontitis), teeth (decayed, missing or filled teeth >20), mucosa (>10% had mucosal lesions) and denture problems (up to 40%) were prevalent and were associated with a poor OHRQoL, especially in females, socially deprived residents or those with mild or above cognitive impairment. Those with a poor OHRQoL might show signs of poor nutrition. Conclusions: This report reviewed evidence-based knowledge on oral health, the OHRQoL and the associated factors among elderly institutional residents. Further research is needed to confirm these observations. For improved oral health, a better OHRQoL and the general well-being of older residents, clinical trials are needed, targeting modifiable factors, such as social inequality, oral healthcare accessibility, and/or nursing home service quality. The relationship between oral health, the OHRQoL and nutrition in this at-risk population also warrants exploration.

Non-surgical periodontal therapy with adjunctive chlorhexidine use in adults with down syndrome: a prospective case series.

BACKGROUND: Subjects with Down syndrome (DS) experience a high prevalence of periodontal disease, and the management of this disease in subjects with DS is a challenge for oral health care providers. The purpose of this case series was to follow the periodontal healing response changes over a 12-month period after non-surgical mechanical periodontal therapy with the adjunctive use of chlorhexidine and monthly recalls in adults with DS who presented initially with chronic periodontitis. METHODS: Twenty-one subjects with DS (14 males and seven females; 25.3 +/- 5.5 years of age) with reported mild-to-moderate learning disabilities and chronic periodontitis were recruited and treated by non-surgical mechanical periodontal therapy (followed by monthly recalls) and the adjunctive use of chlorhexidine gel for toothbrushing and chlorhexidine mouthwash twice daily. Clinical data were recorded. RESULTS: After 12 months of non-surgical mechanical periodontal therapy, the mean percentage of sites with plaque decreased from 84.1% to 23.6%, and the mean number of sites with bleeding on probing decreased from 82.1% to 29.5%. Mean probing depth decreased from 3.2 to 1.8 mm, with a mean clinical attachment level gain of 0.6 mm. CONCLUSIONS: Satisfactory healing responses were achieved following non-surgical mechanical periodontal therapy with the adjunctive use of chlorhexidine and monthly recalls in adults with DS with chronic periodontitis and mild-to-moderate learning disabilities. Such a treatment regimen seems appropriate and beneficial for adults with DS and chronic periodontitis.

A community study on the relationship of dental anxiety with oral health status and oral health-related quality of life.

OBJECTIVE: To investigate the relationship of dental anxiety with oral health status and oral health-related quality of life (OHQoL) among dentate subjects living in Hong Kong. METHODS: One thousand Hong Kong residents who were aged 25-64 years and predominantly Chinese were asked to complete the Chinese short-forms of the Dental Anxiety Inventory (SDAxI) and Oral Health Impact Profile (OHIP-14S). Dental (DMFT index) and periodontal statuses [full-mouth clinical attachment level (CAL)] were also assessed. RESULTS: Ninety-six (9.6%; mean SDAxI, 9.6), 799 (79.9%; mean SDAxI, 15.0), and 105 (10.5%; mean SDAxI, 27.4) participants had low, average, and high dental anxiety, respectively. The mean DMFT/CAL scores of each SDAxI subgroup were 8.5/1.4, 9.3/1.9, and 9.8/3.6, respectively. The corresponding mean OHIP-14S scores for each SDAxI subgroup were 4.0, 8.1, and 13.2, respectively. Post hoc analysis, adjusted for possible confounding factors, revealed statistically significant differences in DMFT and CAL scores in subjects with low versus high level of SDAxI, and significant differences in OHIP-14S scores between all 3 SDAxI categories. CONCLUSION: The trait disposition of dental anxiety may be a significant risk indicator of poor dental and periodontal status and is associated with a worse OHQoL.