David Herrera

This paper presents a model for simulating cultural differences in the conversational behavior of virtual agents. The model provides parameters for differences in proxemics, gaze and overlap in turn taking. We present a review of literature on these factors and show results of a study where native speakers of North American English, Mexican Spanish and Arabic were asked to rate the realism of the simulations generated based on different cultural parameters with respect to their culture.

This paper presents a model for simulating cultural differences in the conversational behavior of virtual agents. The model provides parameters for differences in proxemics, gaze and overlap in turn taking. We present a review of literature on these factors and show results of a study where native speakers of North American English, Mexican Spanish and Arabic were asked to rate the realism of the simulations generated based on different cultural parameters with respect to their culture.

Medline, Embase, The Cochrane Oral Health Group's Trials Register, CENTRAL, UK National Research Register, ISI Proceedings, hand search of relevant journals for 2000-2008. References from selected articles and contact with authors. Randomised controlled trials in any language comparing scaling and root planing (SRP) alone and SRP with PDT in patients with chronic periodontitis, with a mean follow up of at least 12 weeks. The primary outcome measure was the change in clinical attachment loss (CAL). Secondary outcomes were changes in probing depth (PD) and gingival recession (GR). Data were extracted by a single reviewer using a standard extraction form. Quality was assessed using both the Jadad scale and the allocation concealment component of the Cochrane risk of bias tool. Meta-analysis was conducted using the random effects model. Heterogeneity was assessed using the chi-squared-based Q statistic method and Higgins' I(2) test. Four trials with 101 participants were included. The risk of bias of these trials was considered to be moderate. The mean difference in CAL at 12 weeks was 0.29 mm (95% CI 0.08-0.50, p=0.007). Heterogeneity was high using both the Chi(2) and I(2) tests. The review suggests there may be a minor improvement in clinical attachment loss at 12 weeks. It is unclear whether this is a clinically meaningful improvement.

Due to its location and functions, the tongue is one of the most important anatomic structures in the oral cavity. However, knowledge in regards to its role and implications in oral health and disease is scarce. Moreover, although the dorsum of the tongue seems to harbour one of the most complex microbiological niches in human ecology, the knowledge of the role of tongue flora in health and disease is also very limited. Similarly, the nature of the tongue coating and the factors that influence its development and composition are almost unknown. The interest in the study of the tongue niche has increased in recent years due to its association with oral halitosis and to its role as a suitable reservoir for periodontal pathogens. The structure of the tongue favours a unique and complex bacterial biofilm, in which periodontal pathogens are frequently found. However, little is known about how to control this bacterial niche, and factors affecting tongue coating composition and aspect are not fully understood. Studies available on the influence of mechanical or antimicrobial approaches against tongue biofilm are very limited. Mechanical treatments showed a transient reduction in halitosis-related variables but were limited in time. Different antimicrobials agents have been evaluated: chlorhexidine, chlorine dioxide, metal ions, triclosan, formulations containing essential oils , and hydrogen peroxide. However, most studies were designed as short-term models. Some of these studies demonstrated that the reduction in halitosis-related variables was associated with significant changes in the tongue microflora.

Clinical research assessing different therapeutic protocols aimed at treating oral halitosis is scarce. The aim of this study was to evaluate the effects of a combined mechanical and pharmacological approach to treat oral halitosis on clinical and microbiological outcomes on patients followed for 3 months.

AbstractBackground/aims: The periodontal abscess is a frequent periodontal condition in which periodontal tissues may be rapidly destroyed. Its importance is based on the possible need of urgent care, the affectation of tooth prognosis, and the possibility of infection spreading. There is scant information in the scientific literature regarding this condition and most of it has been published as case reports and text books, where conclusions are not evidence-based, but rather empirical observations made by recognised clinicians. The aim of this review was to critically analyse all available information on this subject in the dental and medical literature, including information on its prevalence, proposed etiologies and pathogenesis, diagnosis, microbiology and treatment alternatives.The periodontal abscess is the 3rd most frequent dental emergency, and it is specially prevalent among untreated periodontal patients and periodontal patients during maintenance. Different etiologies have been proposed, and 2 main groups can be distinguished, depending on its relation with periodontal pockets. In the case of a periodontitis-related abscess, the condition may appear as an exacerbation of a non-treated periodontitis or during the course of periodontal therapy. In non-periodontitis related abscesses, impactation of foreign objects, and radicular abnormalities are the 2 main causes. The abscess microflora seems to be similar to that of adult periodontitis, and it is dominated by gram-negative anaerobic rods, including well-known periodontal pathogens. Complications and consequences include tooth loss and the spread of the infection to other body sites. Diagnosis and treatment is mainly based on empiricism, since evidence-based data are not available. The rôle of systemic antibiotics, in the treatment of periodontal abscesses, is especially controversial.

AbstractBackground/aims: The aim of this short-term open parallel longitudinal clinical study was to compare the clinical and microbiological efficacy of 2 different antibiotic regimes in the treatment of acute periodontal abscesses.Method: After patient selection, a clinical examination was carried out recording the following variables: pain, edema, redness, swelling, bleeding on probing, suppuration, tooth mobility, lymphadenopathy, and probing pocket depth. Microbiological samples were taken from the lesion and the patient was randomly assigned to one of two antibiotic regimes: azithromycin or amoxicillin/clavulanate. Clinical variables were recorded, and microbiological samples were taken, at 3–5 days, 10–12 days and 30 days. Additional mechanical treatment (debridement and scaling) was performed in the third visit (10–12 days). Blood and urine samples were collected at baseline and after 10–12 days. Microbiological samples were processed by anaerobic culturing, and isolated periodontal pathogens were tested for antibiotic susceptibility by means of the spiral gradient endpoint methodology.Results: 15 patients took azithromycin, and 14 amoxicillin/clavulanate. Subjective clinical variables demonstrated statistically significant improvements with both antibiotic regimes, which lasted for at least 1 month (p<0.01). Objective clinical variables also showed clear improvements, being statistically significant after 30 days with probing pocket depth in the azithromycin group (p<0.01). Microbiologically, short-term reductions were detected with both antibiotics, however fast recolonization occurred after the third visit. No significant differences were found between both treatment regimes. Antibiotic susceptibilities demonstrated no resistances for amoxicillin/clavulanate, while 2–3 strains of each studied pathogen were resistant to azithromycin.Conclusions: However, both antibiotic regimes were effective in the short-term treatment of periodontal abscesses in periodontitis patients.

AbstractObjectives: The aim was to answer three relevant questions: can systemic antimicrobials be efficacious if the biofilm is not disrupted? Can the type of debridement of the subgingival biofilm impact upon the clinical outcomes of the adjunctive antimicrobial therapy? Is the efficacy of the adjunctive systemic antimicrobial therapy dependent on the quality of the debridement of the subgingival biofilm and the sequence debridement–antibiotic usage?Material and Methods: Relevant papers were searched, critically analysed and their data were extracted.Results: For the first question, studies assessing susceptibility of bacteria in biofilms, and clinical studies evaluating systemic antimicrobials as monotherapy, were reviewed. For the second question, clinical studies comparing systemic antimicrobials as adjuncts to non-surgical debridement or to periodontal surgery and clinical trials using systemic antibiotics with periodontal surgery were evaluated. For the third question, a previous systematic review was updated.Conclusion: If systemic antimicrobials are indicated in periodontal therapy, they should be adjunctive to mechanical debridement. There is not enough evidence to support their use with periodontal surgery. Indirect evidence suggests that antibiotic intake should start on the day of debridement completion, debridement should be completed within a short time (preferably <1 week) and with an adequate quality, to optimize the results.

Countries with a high per capita antibiotic use frequently demonstrate a high level of drug resistance. The aim of this study was to compare the prevalence and levels of beta-lactamase producing bacteria in the subgingival microflora in adult patients with periodontitis in Spain and The Netherlands, and to characterise beta-lactamase producing bacteria in both patient samples. Patients with moderate to severe periodontitis were consecutively selected and asked to report on: current systemic disorders and medications, history of use of antibiotics, and smoking habits. Clinical variables included probing pocket depth, clinical attachment level, plaque, bleeding on probing, and suppuration. Pooled subgingival samples of 4 selected sites were anaerobically cultured in blood agar plates with and without amoxicillin, and amoxicillin/clavulanate. Bacterial colonies growing on amoxicillin plates but not on amoxicillin/clavulanate plates were tested for beta-lactamase production. beta-lactamase producing bacteria were isolated and identified. 31 patients were studied in the Spanish group and 30 in the Dutch group. Comparable mean gender and ages were found. Evaluation of previous antibiotic use revealed that, in the previous 12 months, 54.8% of patients in the Spanish group and 10% in the Dutch group reported antibiotic use (p&amp;lt;0.001). The prevalence of beta-lactamase producing bacteria was 87.1% in the Spanish group and 73.3% in the Dutch group. Total counts of beta-lactamase producing bacteria on amoxicillin plates (p&amp;lt;0.01), the mean number of different beta-lactamase producing colonies per patient (p&amp;lt;0.001), and the number of amoxicillin resistant colonies (p&amp;lt;0.001) were significantly higher in the Spanish group. 74 beta-lactamase producing strains in the Spanish group and 33 in the Dutch group were isolated for identification. 23 out of 35 identified strains in the Spanish group, and 32 out of 33 in the Dutch group belonged to Prevotella genus. A high prevalence of beta-lactamase producing bacteria has been evaluated in two distinct populations, belonging to two European countries with clear differences in antibiotic usage policy. A higher prevalence and a more complex beta-lactamase producing microflora, were found in the Spanish group, associated with a higher antibiotic consumption. This study shows that a higher use of beta-lactam antibiotics is reflected in the % of beta-lactamase producing bacteria in the subgingival microflora of patients with periodontitis. This information may be important in the treatment of severe periodontitis.

Certain specific bacterial species from the subgingival biofilm have demonstrated aetiological relevance in the initiation and progression of periodontitis. Among all the bacteria studied, three have shown the highest association with destructive periodontal diseases: Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg) and Tannerella forsythensis (Tf). Therefore, the relevance of having accurate microbiological diagnostic techniques for their identification and quantification is clearly justified.

AbstractBackground and Aim: Antimicrobial resistance of periodontal pathogens towards currently used antibiotics in periodontics has been investigated in a previous study. Microbial resistance in the periodontal microflora was more frequently observed in Spanish patients in comparison with Dutch patients. The aim of the present study was to compare antimicrobial susceptibility profiles of five periodontal bacteria isolated from periodontitis patients in Spain and in the Netherlands.Material and Methods: Subgingival plaque samples from adult patients with periodontitis were collected and cultured on selective and non-selective plates. Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum and Micromonas micros were isolated and used for minimal inhibitory concentration tests using the Epsilometer (E-test) technique. Eight different antibiotics were tested on all bacterial isolates. MIC50 and MIC90 values for each antibiotic and each species were determined and the percentage of resistant strains was calculated.Results: Significantly higher MIC values were noted in Spanish strains of F. nucleatum for penicillin, ciprofloxacin, of P. intermedia for penicillin, amoxicillin and tetracycline, of M. micros for tetracycline, amoxicillin and azithromycin, and of P. gingivalis for tetracycline and ciprofloxacin. Based on breakpoint concentrations, a higher number of resistant strains in Spain were found in F. nucleatum for penicillin, amoxicillin and metronidazole, in Prevotella intermedia for tetracycline and amoxicillin, and in A. actinomycetemcomitans for amoxicillin and azithromycin. Resistance of P. gingivalis strains was not observed for any of the antibiotics tested both in Spain and the Netherlands.Conclusions: Differences exist in the susceptibility profiles of periodontal pathogens isolated from periodontitis patients in Spain and in the Netherlands. This implicates that antibiotic susceptibility testing is necessary to determine efficacy of antimicrobial agents. Also, clinical studies with antibiotics should take these differences into account. The information from the present study indicates that it may not be possible to develop uniform protocols for usage of antibiotics in the treatment of severe periodontitis in the European Union.

To evaluate the in vitro and in vivo antimicrobial activity of four commercial 0.12% chlorhexidine mouthrinses. The in vitro antimicrobial activity test consisted in a modified contact test where 20 selected bacterial species were tested during 1 min with each test product. After the contact, the inoculum was cultured, and the results were expressed in terms of survival/resistance and the percentage of survival as compared to a saline control. The in vivo test consisted of a double-blind, randomized, crossover salivary bacterial counts study. 10 volunteers rinsed during 1 min with each tested product. Saliva samples were obtained before rinsing, and after 5 min, and 1, 3, 5 and 7 h. These samples were cultured both aerobically and anaerobically. Percentages of survival, in regard to baseline, were calculated for each time point. Comparisons among products were tested using anova and selected paired t-test. The in vitro contact test showed no survival in any tested species with CHX+CPC, while three species (Lactobacillus casei, Streptococcus mitis and Peptostreptococcus micros) were resistant to the other three products. CHX and CHX+NaF demonstrated additional resistant species (three and four species, respectively). The in vivo salivary bacterial counts test showed higher reductions of CHX+CPC and CHX+ALC in aerobic and anaerobic bacteria, lasting for 5 h. Significant differences were detected at multiple time points, when these two products were compared both with the control and the other tested products. Important differences in activity, among 0.12% CHX products, were detected by both in vitro and in vivo tests. The formulation with alcohol was more active than those without alcohol, excepting the formulation with CHX+CPC, in which the reformulation and addition of CPC not only compensate but rather increase the antimicrobial activity.

The aim of this double-blind, parallel study was to test the clinical efficacy of a newly developed mouthrinse in the treatment of oral halitosis in patients without periodontitis. Forty volunteers, recruited in two centers, participated in this study. Patients were selected on the basis of (1) halitosis of oral origin, (2) full-mouth organoleptic score&amp;gt;1, using an arbitrary 0-5 scale, (3) level of volatile sulfur compounds (VSC)&amp;gt;170 parts per billion (ppb) and (4) Winkel tongue coating index (WTCI)&amp;gt;4 (0-12). Intervention included gargling with a mouthrinse containing chlorhexidine (0.05%), cetylpyridinium chloride (0.05%) and zinc-lactate (0.14%) or with a placebo mouthrinse without active ingredients. At days 0 and 14 clinical variables were assessed in order of performance: (1) organoleptic assessments, (2) levels of VSC, and (3) WTCI. Treatment with the active mouthrinse resulted in a significant mean reduction in the organoleptic score from 2.8 to 1.5 (p&amp;lt;0.005). In the placebo group, no significant reduction in the mean organoleptic score occurred. Consequently, this resulted, after 2 weeks, in a greater change of the organoleptic scores in the test group in comparison to the placebo group (p&amp;lt;0.005). The mean VSC scores were reduced from 292 to 172 ppb in the test group (p&amp;lt;0.005), whereas no reduction was observed in the placebo group. At the 2-week examination, the mean change of the VSC scores in the test group was significantly greater than the mean change in the placebo group (p&amp;lt;0.005). Neither in the test nor in the placebo group a significant reduction in tongue coating was observed. In conclusion, the tested mouthrinse is effective in the treatment of oral halitosis.

Scaling and root planing (SRP) are the bases of non-surgical therapy in the treatment of periodontitis. However, results from this therapy are often unpredictable and dependable from many different factors. The aim of this systematic review was to evaluate the effectiveness of the adjunctive use of systemic antimicrobials with scaling and root planing (SRP) vs. SRP alone in the treatment of chronic (CP) or aggressive periodontitis (AgP). Use of computerized databases, namely MEDLINE, the Cochrane Oral Health Group Specialty Trials Register and EMBASE; reference lists from relevant articles were hand-searched; and a hand-search of selected journals until April 2001. Studies were selected if they were designed as controlled clinical trials in which systemically healthy patients with either AgP or CP were treated with SRP plus systemic antimicrobials in comparison with SRP alone or with placebo, for a minimum of 6 months. Main outcome measures were clinical attachment level (CAL) change and probing pocket depth (PPD) change. Two reviewers extracted independently information regarding quality and study characteristics, in duplicate. Kappa scores determined their agreement. Main results were collected and grouped by drug, disease and PPD category. For the quantitative data synthesis, the data was pooled (when mean differences and standard errors were available), and either a Fixed Effects or Random Effects meta-analysis was used for the analysis. After an initial selection, 158 papers were identified by the manual and electronic searches; 25 papers were eligible for inclusion. Their quality assessment showed that randomization and allocation concealment methods were seldom reported and blindness was usually not defined clearly. In general, selected studies showed high variability and lack of relevant information for an adequate assessment. Overall, SRP plus systemic antimicrobial groups demonstrated better results in CAL and PPD change than SRP alone or with placebo groups. Only limited meta-analyses could be performed, due to the difficulties in pooling the studies and the lack of appropriate data. This analysis showed a statistically significant additional benefit for spiramycin (PPD change) and amoxicillin/metronidazole (CAL change) in deep pockets. Systemic antimicrobials in conjunction with SRP, can offer an additional benefit over SRP alone in the treatment of periodontitis, in terms of CAL and PPD change, and reduced risk of additional CAL loss. However, differences in study methodology and lack of data precluded an adequate and complete pooling of data for a more comprehensive analyses. It was difficult to establish definitive conclusions, although patients with deep pockets, progressive or &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;active&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; disease, or specific microbiological profile, can benefit more from this adjunctive therapy.

To evaluate the clinical and microbiological activity of a new mouth rinse formulation, used as an adjunct to oral hygiene, for patients in supportive periodontal care. This was a randomized, placebo-controlled clinical trial with two groups: test group, rinsing twice per day with the test product (with 0.05% chlorhexidine and 0.05% cetylpyridinium chloride); and control group, rinsing with a placebo. Treated chronic periodontitis patients were included, and two visits were rendered, baseline, and after 15 days. Clinical outcome variables included plaque and gingival indices, and probing pocket depth. Subgingival samples were processed by culturing. Patient-based variables and adverse effects were also assessed. Outcome variables were compared by t-test, chi2, and Mann-Whitney test. The results belonged to 33 patients. Plaque and gingival indices, and the log of bacterial total counts were reduced in the test group (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.01), but differences between groups were only statistically significant (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) for plaque and bacterial counts. A significant reduction in the proportions of flora (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) and frequency of detection (p = 0.01) of Porphyromonas gingivalis was observed in the test group. The newly formulated mouth rinse demonstrated short-term plaque-inhibitory activity. This was associated with a reduction in the total load of anaerobic subgingival microflora.

AbstractBackground/aims: Little information is available regarding the diagnosis and microbiology of periodontal abscesses. The aim of this descriptive clinical and microbiological study was to provide more information in order to help in the characterisation of the periodontal abscess associated to periodontitis.Method: 29 consecutive patients with a periodontal abscess were studied by the assessment of clinical variables, including both subjective (pain, edema, redness and swelling) and objective (bleeding on probing, suppuration, probing pocket depth, tooth mobility and cervical lymphadenopathy) parameters. Microbiological samples were taken for anaerobic microbiology and processed by means of culture. Systemic involvement was also studied through the analysis of blood and urine samples using conventional laboratory standards.Results: 62% of the abscesses affected untreated periodontitis patients, and 69% were associated with a molar tooth. More than 75% of the abscesses had moderate-severe scores related to edema, redness and swelling, and 90% of the patients reported pain. Bleeding occurred in all abscesses, while suppuration on sampling was detected in 66%. Mean associated pocket depth was 7.28 mm, and 79% of teeth presented some degree of mobility. Cervical lymphadenopathy was seen in 10% of patients, while elevated leucocyte counts were observed in 31.6%. The absolute number of neutrophils was elevated in 42% of the patients. High prevalences of putative periodontal pathogens were found, including Fusobacterium nucleatum, Peptostreptococcus micros, Porphyromonas gingivalis, Prevotella intermedia and Bacteroides forsythus.Conclusions: The periodontal abscess has clear clinical characteristics and is usually associated with severe periodontal destruction. This condition may cause systemic involvement and the lesion generally has a large bacterial mass with a high prevalence of well-recognised periodontal pathogens.

This study evaluated the microbial effects of a newly formulated mouthwash (Halita) on oral halitosis patients. Forty subjects were included in this dual-centre, double-blind, placebo-controlled parallel study. Inclusion and exclusion criteria were used to select patients. At baseline and at 2 weeks post-treatment, full-mouth organoleptic odor scores, level of volatile sulphur compounds (VSC) and the Winkel Tongue Coating Index were recorded. Standardized samples of tongue coating, saliva and subgingival plaque were microbiologically investigated. Participants were randomly assigned to the test or placebo groups. High prevalences were observed for Fusobacterium nucleatum, Prevotella intermedia and Porphyromonas gingivalis in tongue coating, saliva and subgingival plaque samples. A significant positive correlation between baseline total counts of P. gingivalis in saliva samples and organoleptic and VSC scores was found. Two weeks post-treatment there was a reduction in total anaerobic counts in all samples in the test group. A significant positive correlation was observed between the reduction in total counts in saliva samples and the reduction in organoleptic scores in the test group. Significant reductions in total counts and proportions of F. nucleatum and total counts of P. intermedia in tongue coating samples were observed in the test group. The test mouthwash demonstrated efficacy in reducing the microbiological parameters in three oral niches in moderate to severe halitosis patients without periodontitis, and this was correlated with the improvements in organoleptic and VSC scores but not with the tongue coating scores.