Detection of Frank's sign in the dental setting: A population-based cohort study.

BACKGROUND: In 1973, Saunders T. Frank described the diagonal earlobe crease (DELC) as a potential marker of cardiovascular disease. However, this anatomical finding is not routinely examined. The aim of this study was to assess the presence of this crease in the general population attending a dental setting and describe its anatomical variations to be able to categorize it as a physical sign. METHODOLOGY: A study group of 1050 white adults were selected, as participants in the framework of the "A Estrada Study of Glycation and Inflammation" (AEGIS), a cross-sectional, population-based descriptive study of a representative sample of the general adult population of the municipality of A Estrada (Pontevedra, Spain). Each participant's age, sex, and preferred head position when sleeping were recorded. Both earlobes were visually inspected and the anatomical variables of the crease were recorded (unilateral or bilateral, length, depth, and presence of secondary creases). The relationship between the study variables was analyzed using the chi-squared test, Student's t-test, the analysis of variance (ANOVA), and the nonparametric tests of Mann-Whitney and Kruskal-Wallis. RESULTS: The DELC was observed in 65.2% of the participants. In 71.5% of the cases, the sign was complete (occupying the space from the tragus to the posterior edge of the earlobe); in 56.9% of the cases, the sign was bilateral; in 45.1% of the cases it was deep; and in the 43.6% of the cases, accessory creases were identified. Neither sex nor the habitual head position when sleeping were related to the prevalence or characteristics of the DELC. The prevalence, extent and depth of Frank's sign increased significantly with age (p < .001). CONCLUSION: The prevalence of the DELC increases significantly with age, and its morphological characteristics are accentuated. This finding, therefore, gains special relevance as a marker of potential cardiovascular disease when observed in young adults.

Discrepancy in medications reported by elderly patients in the dental office and in their electronic medical records: A pilot study.

AIMS: This study's main objective was to analyze the discrepancy between the dental medication record (DMR) and the physician-prescribed active medications recorded in the medical medication record (MMR). METHODS: The study group consisted of 100 adults who attended the University Dental Clinic (Santiago de Compostela, Spain) requesting dental care. A dental history was created for all participants that included the DMR. The MMR were compiled from their electronic medical records. RESULTS: About 80% of the patients consumed at least one drug (94.2% of those >65 years) and 19% took more than five drugs (26.4% of those > 65 years). In total, 54% of the patients had some discrepancy between the medications recorded in the DMR and those in the MMR (48.4% for those ≤65 years and 64.7% for those >65 years). The rate of participants who omitted some drugs was higher for those >65 years. The drugs most omitted from the DMR were analgesics/opioids, antihypertensives and anxiolytics/hypnotics/sedatives. CONCLUSIONS: It is imperative to access the MMR of patients requesting dental care because a significant number of medications are not reflected in their DMR. These discrepancies may be particularly common and relevant in elderly patients, in whom multimorbidity and polypharmacy are more frequent.

Dental desensitization by dentists and occupational therapists for autistic adults: A pilot study.

LAY ABSTRACT: Managing patients with autism in the dental clinic often requires resorting to pharmacological behavioral control techniques, including general anesthesia. References in the literature to desensitization programs are scarce and focus on training children with autism to undergo oral examinations and preventive procedures. This study shows that a dental desensitization program implemented by dentists and occupational therapists could help in performing not only oral examinations but also simple dental therapeutic procedures for a considerable percentage of adults with autism, without using a pharmacological intervention (sedation or general anesthesia).

Frank's Sign and Cardiovascular Risk: An Observational Descriptive Study.

PURPOSE: This study was undertaken to analyze the relationship between the diagonal earlobe crease and the main indices of cardiovascular risk, considering the crease's anatomical variations. METHODS: The study group consisted of 1050 adults residing in Spain. Participants underwent the following determinations: age, sex, body mass index, smoking habit, blood pressure, glycemia, glycated hemoglobin, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and cardiovascular events. Cardiovascular risk was calculated applying the Framingham-Anderson equation, the Systematic Coronary Risk Evaluation equation, and the Atherosclerotic Cardiovascular Disease Risk Score calculator. Both earlobes were examined, recording diagonal earlobe crease presence, length and depth, and presence of accessory creases. Results were analyzed by using chi-square test, Student's t test, analysis of variance, and Mann-Whitney or Kruskal-Wallis tests. To extract the functions of cardiovascular risk, a script in R was created (https://cran.r-project.org/). RESULTS: The estimated cardiovascular mortality risk was significantly higher in individuals who presented diagonal earlobe crease (P < .001). The number of individuals with moderate, high, or very high cardiovascular risk increased significantly as the presence of the crease increased (23.8% had no crease, 35.6% had unilateral creases, and 58% had bilateral creases; P < .001). The mean cardiovascular risk estimated was significantly higher for individuals with longest and deepest diagonal earlobe crease (P < .001 and P < .001, respectively), and with accessory creases (P < .001). CONCLUSIONS: The diagonal earlobe crease is independently associated with higher cardiovascular risk scores, especially when the crease is complete, bilateral, deep, and has accessory creases.

Anti-caries Streptococcus spp.: A potential preventive tool for special needs patients.

INTRODUCTION: Probiotics are living microorganisms that act on the host-microbiome interface to restore the microbiota's physiological homeostasis. Numerous probiotics have been marketed with inhibitory activity against Streptococcus mutans and consequently with a potential anti-caries effect, mainly of the genera Lactobacillus and Bifidobacterium, whose main disadvantage is their limited ability to settle in the oral cavity. METHODS: This narrative review describes the main Streptococcus spp. with probiotic anti-Streptococcus mutans activity, whose substantivity is greater than that of Lactobacillus spp. and consequently with anti-caries potentiality. We performed a literature review in the PubMed, Science Direct and Google Scholar databases of articles published in English (without time restriction) related to caries and probiotics. RESULTS: The potential identified anti-caries probiotics included Streptococcus spp. A12, Streptococcus oralis (AJ3), Streptococcus oligofermentans, Streptococcus salivarius (K12, M18, JH, LAB813, 24SMB), Streptococcus spp. with arginolytic activity (S. sanguinis, S. gordonii, S. ratti, S. parasanguinis, S. intermedius, S. australis, and S. cristatus), Streptococcus rattus (JH145), Streptococcus dentisani and Streptococcus downii. CONCLUSIONS: The possibility of using these Streptococcus spp. as probiotics that inhibit the growth of dental plaque and the development of carious lesions represents a potential tool of particular interest for individuals with physical or intellectual disabilities that impede the routine and effective application of mechanical dental plaque removal techniques.

Mechanism of Action of Streptococcus downii, a New Bacterial Species with Probiotic Potential.

Streptococcus downii is a recently reported bacterial species of oral origin, with inhibitory capacity against Streptococcus mutans, Actinomyces naeslundii, Veillonella parvula and Aggregatibacter actinomycetemcomitans, which confers upon it the potential of being an oral probiotic. The aim of the present study was to identify the potential mechanisms by which S. downii exerts its inhibitory effect on S. mutans. To this end, the study assessed the consumption of glucose and proteins available in the culture medium, the modification of the pH, the production of short-chain fatty acids, the changes in the protein panel of the inhibition halo, the production of hydrogen peroxide and the effect of proteinase K. There were no differences in the glucose values or in the protein content of the medium, but there was a reduction in pH (with no effect on the growth of S. mutans). Significant increases were detected in the levels of lactic and formic acid (with no effect on the growth of S. mutans), as well as changes in the peptide panel (with no effect on the growth of S. mutans). The inhibitory effect was maintained in the presence of peroxidase but disappeared after adding proteinase K. Based on these results, it is suggested that the main mechanism of inhibition of S. downii against S. mutans is the production of bacteriocins.

Efficacy of Ciprofloxacin, Metronidazole and Minocycline in Ordered Mesoporous Silica against Enterococcus faecalis for Dental Pulp Revascularization: An In-Vitro Study.

Pulp revascularization of teeth with necrotic pulp has become an alternative treatment in cases with immature apex. Microbial control is essential to achieve a successful outcome and continued root development. Enterococcus faecalis (E. faecalis) is the most frequently isolated bacterial species in root canals of endodontically failed teeth. Our main goal was to compare the in-vitro antimicrobial efficacy of different antibiotic formulations delivered by ordered mesoporous silica (OMS) against E. faecalis. To determine antibiotic susceptibility, we tested OMS and triple antibiotic paste (TAP; ciprofloxacin:metronidazole:minocycline) with different reagents in different concentrations, using the Kirby−Bauer disk diffusion method. OMS and metronidazole showed no antibacterial activity against E. faecalis. Mixtures of OMS and antibiotics in proportions of 2:2:14 and 4:1:7 (mg/L of ciprofloxacin:metronidazole:minocycline, respectively) showed the lowest antibacterial activity. The antibacterial activity of the combined solutions of ciprofloxacin and metronidazole was significantly higher (p < 0.005). Combinations in different concentrations of minocycline, ciprofloxacin, and metronidazole in OMS have shown activity against E. faecalis, although the combined use of ciprofloxacin and metronidazole has shown the most effective results. This study demonstrates the efficacy of intracanal antibiotic combination paste activity against E. faecalis, avoiding the use of minocycline, whose undesirable effect of teeth staining is a common problem for patients and professionals in dental clinic.

Evaluation of Intraligamentous and Intraosseous Computer-Controlled Anesthetic Delivery Systems in Pediatric Dentistry: A Randomized Controlled Trial.

Computer-controlled local anesthetic delivery systems (CDS) represent one of the resources that have progressed the most in recent years, but their efficacy and applicability in pediatric dentistry is still the subject of certain controversies. This randomized, controlled, split-mouth clinical trial assessed two CDS in children (n = 100) with deep caries in the temporary dentition that required invasive therapeutic procedures, using inferior alveolar nerve block as the gold standard. Half of the patients (n = 50) underwent the intraligamentary technique (Wand STA®) on one side of the mouth and conventional inferior alveolar nerve block on the contralateral side, while the other half (n = 50) underwent the intraosseous technique (QuickSleeper®) on one side of the mouth and conventional inferior alveolar nerve block on the contralateral side. The following were considered covariates: age, sex, type of dental procedure and the applied local anesthesia system. The outcome variables were the pain caused by the anesthesia injection, the physical reaction during the anesthesia injection, the need for anesthetic reinforcement, pain during the therapeutic procedure, the overall behavior during the visit, the postoperative morbidity and, lastly, the patient's preference. In conclusion, we confirmed the efficacy of intraligamentary and intraosseous techniques administered using a CDS for conducting invasive dental treatments in children, their advantages compared with inferior alveolar nerve block in terms of less pain generated by the anesthesia injection and less postoperative morbidity, as well as the pediatric patients' preference for CDS versus conventional techniques.

Effect of mesoporous silica and its combination with hydroxyapatite on the regeneration of rabbit's bone defects: A pilot study.

BACKGROUND: Bone volume augmentation is a routine technique used in oral implantology and periodontology. Advances in the surgical techniques and the biomaterials field have allowed a greater accessibility to these treatments. Nevertheless, dehiscence and fenestrations incidence during dental implant procedures are still common in patients with bone loss. OBJECTIVE: The main objective is to evaluate in a pilot experimental study the biological response to mesoporous silica (MS) hybrid scaffolds and its regenerative capacity in different formulations. METHODS: Two defects per rabbit tibia were performed (one for control and other for test) and the biomaterials tested in this study have been used to fill the bone defects, prepared in two different formulations (3D hybrid scaffolds or powdered material, in 100% pure MS form, or 50% MS with 50% hydroxyapatite (HA). Euthanasia was performed 4 months after surgery for bone histopathological study and radiographic images were acquired by computerized microtomography. RESULTS: Results showed that radiographically and histopathologically pure MS formulations lead to a lower biological response, e.g when formulated with HA, the osteogenic response in terms of osteoconduction was greater. CONCLUSIONS: We observed tolerance and lack of toxicity of the MS and HA, without registering any type of local or systemic allergic reaction.

Hybrid mesoporous nanostructured scaffolds as dielectric biosimilar restorative materials.

BACKGROUND: The intricate structure of natural materials is in correspondence with its highly complex functional behaviour. The health of teeth depends, in a complex way, on a heterogeneous arrangement of soft and hard porous tissues that allow for an adequate flow of minerals and oxygen to provide continuous restoration. Although restorative materials, used in clinics, have been evolving from the silver amalgams to actual inorganic fillers, their structural and textural properties are scarcely biomimetic, hindering the functional recovery of the tissue. OBJECTIVE: The objective of this work is to compare and test the hybrid mesoporous silica-based scaffolds as candidates for dentine restoration applications. METHODS: In this work, we present the development and the physical properties study of biocompatible hybrid mesoporous nanostructured scaffolds with a chemically versatile surface and biosimilar architecture. We test their textural (BET) and dielectric permittivity (ac impedance) properties. RESULTS: These materials, with textural and dielectric properties similar to dentine and large availability for the payload of therapeutic agents, are promising candidates as functional restorative materials, suitable for impedance characterization techniques in dental studies. CONCLUSIONS: Structural, textural, morphological characterization and electrical properties of hybrid mesoporous show a large degree of similarity to natural dentin samples.

Analysis of the unpredictable migration of impacted mandibular third molars: A pilot study.

BACKGROUND: Eruption of an impacted mandibular third molar (3MM) is often unpredictable. The objective of this study was to establish the radiographic parameters of migration in patients whose 3MMs evolved unpredictably. MATERIAL AND METHODS: This was a retrospective observational study. Patients with unusual 3MM migration (away from their physiological eruption position with changes in the longitudinal and horizontal axes) and with at least two panoramic radiographs were included. To evaluate the radiographic parameters, images were superimposed, using mandibular angle and ipsilateral condyle as references. RESULTS: Of a total of 2851 patients, four were included in our study. The average age of the patients at the time of the second X-ray was 41.75 (SD=8.42) years. The mean follow-up period was 111 (SD=59.09) months. The migration was caudal in three of the 3MMs (75%) and cranial in one (25%). CONCLUSIONS: Unpredictable 3MM migration is rare, and occurs mostly in the vertical direction with an average angle of 12 degrees. None of these migrations were related to any type of lesion. Our results reveal that, due to its unpredictable behaviour, impacted wisdom teeth have to be periodically radiographically evaluated even if surgical extraction is not indicated. Key words:Tooth migration, third molar, ectopic tooth.

Identification of Prognosis Associated microRNAs in HNSCC Subtypes Based on TCGA Dataset.

Background and Objectives: Head and Neck Squamous Cell Carcinoma (HNSCC) includes cancers from the oral cavity, larynx, and oropharynx and is the sixth-most common cancer worldwide. MicroRNAs are small non-coding RNAs for which altered expression has been demonstrated in pathological processes, such as cancer. The objective of our study was to evaluate the different expression profile in HNSCC subtypes and the prognostic value that one or several miRNAs may have. Materials and Methods: Data from The Cancer Genome Atlas Program-Head and Neck Squamous Cell Carcinoma (TCGA-HNSCC) patients were collected. Differential expression analysis was conducted by edge R-powered TCGAbiolinks R package specific function. Enrichment analysis was developed with Diana Tool miRPath 3.0. Kaplan-Meier survival estimators were used, followed by log-rank tests to compute significance. Results: A total of 127 miRNAs were identified with differential expression level in HNSCC; 48 of them were site-specific and, surprisingly, only miR-383 showed a similar deregulation in all locations studied (tonsil, mouth, floor of mouth, cheek mucosa, lip, tongue, and base of tongue). The most probable affected pathways based on miRNAs interaction levels were protein processing in endoplasmic reticulum, proteoglycans in cancer (p < 0.01), Hippo signaling pathway (p < 0.01), and Transforming growth factor-beta (TGF-beta) signaling pathway (p < 0.01). The survival analysis highlighted 38 differentially expressed miRNAs as prognostic biomarkers. The miRNAs with a greater association between poor prognosis and altered expression (p < 0.001) were miR-137, miR-125b-2, miR-26c, and miR-1304. Conclusions: In this study we have determined miR-137, miR-125b-2, miR-26c, and miR-1304 as novel powerful prognosis biomarkers. Furthermore, we have depicted the miRNAs expression patterns in tumor patients compared with normal subjects using the TCGA-HNSCC cohort.

Assessment of the Economic and Health-Care Impact of COVID-19 (SARS-CoV-2) on Public and Private Dental Surgeries in Spain: A Pilot Study.

OBJECTIVES: The COVID-19 (SARS-CoV-2) pandemic is an ongoing public health challenge, also for the dentistry community. The main objective of this paper was to determine the economic and health-care impact of COVID-19 on dentists in the Autonomous Region of Galicia (Spain). METHODS: This was a descriptive observational study in which the data was collected by means of a self-administered survey (from 1 April 2020 to 30 April 2020). RESULTS: A total of 400 dentists from Galicia responded to the survey. Only 12.3% of the participants could obtain personal protective equipment (PPE) including FFP2 masks. Of the male respondents, 33.1% suffered losses >€15,000 compared to 19.4% of female respondents (OR = 3.121, p < 0.001). Economic losses seem to have contributed to the applications for economic help as 29.5% of the respondents who applied for this measure recorded losses in excess of €15,000 (p = 0.03). Patients complained more about the fact that only emergency care was available during the State of Alarm, in dental surgeries that do not work with insurance companies or franchises. Only 4 professionals tested positive, 50% of whom worked exclusively in private practice and the other 50% who practised in both private and public surgeries. Dentists who practise in the public sector saw more urgent patients per week than those practising in private surgeries (p = 0.013). CONCLUSIONS: The COVID-19 pandemic has had economic repercussions in dentistry as only urgent treatment was available during the State of Alarm. These repercussions seem to be higher in male participants, as the majority of the participants have revealed higher economic losses than females. The level of assistance has also been affected, reducing the number of treated patients, although this quantity has been different in private and public surgeries. By presenting these findings we look to highlight the role that dentists play in society in treating dental emergencies in our surgeries, and this must be recognised and addressed by the relevant authorities, who must provide PPEs as a priority to this group as well as providing special economic aid in accordance with the losses incurred by the sector.

In vitro comparison of passive and continuous ultrasonic irrigation in simulated lateral canals of extracted teeth.

INTRODUCTION: Complete endodontic system disinfection requires the removal of vital and necrotic pulp tissue, microorganisms, and toxins. The purpose of this study was to compare the effects of 2 ultrasonic irrigation techniques on the penetration of sodium hypochlorite into the main canal and simulated lateral canals of extracted teeth. METHODS: Two simulated lateral canals each were created 2, 4, and 6 mm from the working length in 60 single-rooted teeth (6 canals/tooth, n = 360). To resemble the clinical situation, a closed system was created in each tooth. The teeth were randomly assigned to 3 experimental irrigation groups: group 1 (n = 20), positive pressure irrigation (PPI); group 2 (n = 20), passive ultrasonic irrigation (PUI); and group 3 (n = 20), continuous ultrasonic irrigation (CUI). Samples were evaluated by direct observation of still images recorded under a dental operating microscope. To examine irrigating solution penetration, 20% Chinese ink (Sanford Rotring GmbH, Hamburg, Germany) was added to a 5% sodium hypochlorite solution and delivered into the root canals. RESULTS: The results showed a significantly higher (P < .05) penetration of irrigant into the lateral canals in the CUI group. PUI and CUI did not differ significantly in solution penetration into the apical thirds of the main canals. The PPI group showed a significantly lower penetration of sodium hypochlorite into the main and lateral canals compared with the CUI and PUI groups. CONCLUSIONS: CUI as a final rinse significantly increased the penetration of irrigating solution into simulated lateral canals.

Relevancia clínica del cepillado dental y su relación con la caries / Clinical relevance of tooth brushing in relation to dental caries

ObjetivoDeterminar el impacto clínico del cepillado dental en la salud bucodental.DiseñoEstudio de prevalencia.EmplazamientoCentro de Salud Fontiñas (Santiago de Compostela).ParticipantesSe estudiaron 281 niños de 5–14 años.Mediciones principalesExploración odontológica según la metodología de la OMS. Se determina la frecuencia de cepillado dental, ingesta de dulces y prevalencia de caries. Análisis mediante regresión logística y estimación de relevancia clínica con el cálculo de la diferencia relativa de prevalencias (DRP) y el número necesario de pacientes por tratar (NNT) para prevenir un episodio.ResultadosLos niños que no se cepillan nunca los dientes tienen un 40% (intervalo de confianza [IC] del 95%: 24,3–57,8) de cariados temporales y los que lo hacen varias veces al día tienen un 15,3% (IC del 95%: 9,4–23,7). Al ajustar por edad, ingesta de dulces, cepillado dental y visita al dentista, se observa una asociación entre no cepillado dental y caries en la dentición temporal (odds ratio: 2,3; IC del 95%: 1,05–5,3) y definitiva (odds ratio: 3.9; IC del 95%: 1,4–10,3).ResultadosLa DRP es del 62% (IC del 95%: 30–79), es decir, la prevalencia de caries es un 62% menor en niños que se cepillan varias veces al día en relación con los que no lo hacen nunca. El NNT es de 4 (IC del 95%: 2,4–14), es decir, por cada 4 niños que se cepillan varias veces al día hay un caso menos de caries en comparación con los que no se cepillan nunca. El efecto de la intervención disminuye al bajar la frecuencia de cepillado. El mismo efecto se observa en cariados definitivos (DRP=55% [IC del 95%: 16–76]; NNT=5 [IC del 95%: 2,8–53,3]).ConclusionesEl cepillado dental se asocia a la salud bucodental, con un gran impacto clínico. El efecto positivo del cepillado dental fue superior al de una dieta correcta(AU)

AimTo determine the impact and clinical relevance of tooth brushing on oral health.DesignPrevalence study.LocationFontiñas Health Centre. (Santiago de Compostela, Spain). Prevalence study (n=281 children aged 5–14 years.LocationOdontological examination according to WHO methodology, to determine the frequency of tooth brushing, frequency of sweet consumption and their impact on the prevalence of caries.Statistical analysisLogistic regression and estimation of the relative prevalence difference (RPD) and the Number Needed to Treat in order to prevent one additional bad outcome (NNT).ResultsThe children who never brush their teeth have a 40% (95% CI: 24.3&%#x02013;57.8%) of early caries, while those who brush their teeth several times a day have 15.3% (95% CI: 9.4&%#x02013;23.7%). An association between not brushing the teeth and caries in primary teeth (OR=2.3; 95% CI:1.05–5.3) was observed after adjusting for age, sweet consumption and visits to the dentist. The same occurred with final teeth (OR=3.9; 95% CI:1.4–10.3).ResultsThe RPD was 62%(95% CI: 30&%#x02013;79%), meaning that prevalence of caries is 62% lower in children who brush their teeth several times a day as compared to those who never brush their teeth. The NNT is 4 (95% CI: 2.4–14), so for every 4 children who brush their teeth several times a day, there is one less case of caries, compared to those who never brush their teeth. There is a dose-response relationship between prevalence of caries and brushing frequency. The same effect was observed with definitive caries: RPD=55% (95% CI:16&%#x02013;76%), NNT=5 (95% CI:2.8–53.3).ConclusionsTooth brushing is related to oral health, with a major clinical impact. The positive effect of tooth brushing was superior to that of a correct diet(AU)

[Clinical relevance of tooth brushing in relation to dental caries]. / Relevancia clínica del cepillado dental y su relación con la caries.

AIM: To determine the impact and clinical relevance of tooth brushing on oral health. DESIGN: Prevalence study. LOCATION: Fontiñas Health Centre. (Santiago de Compostela, Spain). Prevalence study (n=281 children aged 5-14 years. Odontological examination according to WHO methodology, to determine the frequency of tooth brushing, frequency of sweet consumption and their impact on the prevalence of caries. STATISTICAL ANALYSIS: Logistic regression and estimation of the relative prevalence difference (RPD) and the Number Needed to Treat in order to prevent one additional bad outcome (NNT). RESULTS: The children who never brush their teeth have a 40% (95% CI: 24.3%-57.8%) of early caries, while those who brush their teeth several times a day have 15.3% (95% CI: 9.4%-23.7%). An association between not brushing the teeth and caries in primary teeth (OR=2.3; 95% CI:1.05-5.3) was observed after adjusting for age, sweet consumption and visits to the dentist. The same occurred with final teeth (OR=3.9; 95% CI:1.4-10.3). The RPD was 62%(95% CI: 30%-79%), meaning that prevalence of caries is 62% lower in children who brush their teeth several times a day as compared to those who never brush their teeth. The NNT is 4 (95% CI: 2.4-14), so for every 4 children who brush their teeth several times a day, there is one less case of caries, compared to those who never brush their teeth. There is a dose-response relationship between prevalence of caries and brushing frequency. The same effect was observed with definitive caries: RPD=55% (95% CI:16%-76%), NNT=5 (95% CI:2.8-53.3). CONCLUSIONS: Tooth brushing is related to oral health, with a major clinical impact. The positive effect of tooth brushing was superior to that of a correct diet.

Alternating versus continuous rotation: a comparative study of the effect on instrument life.

INTRODUCTION: Rotary nickel-titanium instruments have multiple advantages but with the risk of more fractures because of flexure or torsion. Alternating rotation appears to be an alternative to continuous rotary movement. The objective of this study was to determine the influence of the type of instrument rotation on the frequency of fractures or deformation. METHODS: Instrumentation was performed on 120 molar root canals with an angle of curvature greater than 30 degrees using alternating rotation (group A: 60 degrees clockwise, 45 degrees counterclockwise) and continuous rotation (group B). RESULTS: The results indicate that instruments used with alternating rotation have a higher mean number of uses (13.0) compared with the continuous rotation group (10.05); this difference was statistically significant (p < 0.05). CONCLUSIONS: The ProTaper shaping instruments (S1 and S2) are those that achieved the greatest difference in use with alternating rotation, with S2 being the most resistant to fracture or deformation with the two types of movement used.