Secondary Caries in situ Models: A Systematic Review.

In situ caries research serves as a bridge between clinical research and laboratory studies. In this kind of research, volunteers wear a removable intraoral splint or prosthesis containing research samples. Many different in situ models exist to investigate secondary caries. This systematic review compared currently existing secondary caries models and their lesion progression per day values. MATERIALS AND METHODS: Three databases (Medline, Embase, and Cochrane) were searched for relevant literature. Bias risk was assessed and model parameters and caries-related outcomes were extracted by 2 independent researchers. Where possible, caries-related outcomes were normalized by estimating lesion progression per day by dividing lesion depth extracted from microradiographic or microhardness data by the number of days the study lasted. RESULTS: The literature search identified 335 articles. After eliminating duplicates and selection, 31 articles were included. The models differed greatly on factors such as sample location, presence of fluoride in the model, and analysis methods. Three main groups could be identified by sample placement; 68% of models placed samples palatally in the upper jaw, and the lower jaw model could be divided into the buccal (26%) and approximal (6%) areas. Average lesion progression in enamel next to composite was 4.3 ± 2.8 µm (range1.1-8.8 µm/day). DISCUSSION: Studies conducted with palatal models showed caries progression rates 2-5 times higher than the estimated clinical progression rates. Lesion progression per day could be a useful tool for future comparison of models and establishing a standardized model.

Validez y confiabilidad en investigación odontológica / Validity and reliability in dental research

El proceso de medición consiste en asignar valores numéricos a características del paciente, un nivel de daño, certeza diagnóstica de la enfermedad, entre otros. Sin embargo, existen fenómenos complejos que incluyen conceptos más amplios que requieren de la creación y validación de instrumentos psicométricos para su registro. El objetivo de esta revisión es presentar los conceptos de validez y confiabilidad de instrumentos de medición aplicados en Odontología. Se expone la definición en salud de variables directas e indirectas, la importancia del uso de instrumentos psicométricos, la definición de Validez y Confiabilidad de un instrumento y sus distintas clasificaciones (validez de contenido, de criterio y de constructo; confiabilidad del instrumento y del observador). Además, se presenta algunos ejemplos del proceso de validación de instrumentos, su metodología y forma de análisis de los resultados. De esta forma, presentamos los tópicos necesarios para comprender el proceso de medición usado en nuestro quehacer clínico o en investigación odontológica, con el fin de identificar los instrumentos adecuados (validos y confiables) para nuestras necesidades

The measurement process consists in assigning numerical values to the patient's characteristics, level of injury, diagnostic certainty of the disease, among others. However, there are complex phenomena that include broader concepts, which require the creation and validation of psychometric instruments for its measurement. The aim of this review is to present the concepts of validity and reliability of the instruments used in Dentistry. It exposes health definition of direct and indirect variables, the importance of using psychometric instruments, the definition of Validity and Reliability of an instrument and its different classifications (content validity, criterion and construct; reliability of the instrument and the observer). Furthermore, it presents some examples of the validation process of an instrument, its methodology and analysis of the results. Thus, we present the topics necessary to understand the measurement process used in our clinical work or dental research in order to identify appropriate instruments, considered valid and reliable for our needs

Different response to amine fluoride by Streptococcus mutans and polymicrobial biofilms in a novel high-throughput active attachment model.

BACKGROUND/AIMS: The antimicrobial resistance of microorganisms in biofilms and the polymicrobial interactions in these biofilms that modulate resistance require novel strategies to evaluate the efficacy of caries-preventive compounds. The current study aimed to evaluate the effects of a caries-preventive agent in Streptococcus mutans and polymicrobial biofilms. METHODS: We developed a novel high-throughput active attachment model. The model consisted of a custom-designed lid containing glass discs that fit on top of standard 24-well plates. Biofilms were formed using either S. mutans C180-2 or saliva. At the end of biofilm formation (up to 96 h) the biofilms were treated with amine fluoride (AmF) solutions. The viability of the biofilms was determined by CFU counts, and metabolic activity was measured via lactate production. RESULTS: The effect of AmF on the viability of the polymicrobial biofilms was significantly less than that on the S. mutans biofilms, indicating a higher resistance in the complex biofilms. Both types of biofilms became more resistant to AmF with age. The higher resistance of the polymicrobial biofilms was not reflected in metabolic activity; in dose-response experiments AmF reduced lactate production in both types of biofilms to the same extent. Moreover, the age-induced increased resistance in the polymicrobial biofilms was less pronounced in terms of the inhibition of metabolic activity. CONCLUSIONS: This study clearly shows that when evaluating the efficacy of caries-preventive compounds it is essential to use appropriate polymicrobial biofilm models, and more importantly that efficacy needs to be judged based on the reduction of acid formation (i.e. cariogenic potential) as well as on bacterial viability.

Maximum occlusal bite forces in Jordanian individuals with different dentofacial vertical skeletal patterns.

This study was carried out to record maximum occlusal bite force (MBF) in Jordanian students with three different facial types: short, average, and long, and to determine the effect of gender, type of functional occlusion, and the presence of premature contacts and parafunctional habits on MBF. Sixty dental students (30 males and 30 females) were divided into three equal groups based on the maxillomandibular planes angle (Max/Mand) and degree of anterior overlap: included short-faced students with a deep anterior overbite (Max/Mand < or = 22 degrees), normal-faced students with a normal overbite that served as the controls (Max/Mand = 27 +/- 5 degrees), and long-faced students with an anterior open bite (Max/Mand > or = 32 degrees). Their age ranged between 20 and 23 years. MBF was measured using a hydraulic occlusal force gauge. Occlusal factors, including the type of functional occlusion, the presence of premature contacts, and parafunctional habits, were recorded. Differences between groups were assessed using a t-test and analysis of variance. The average MBF in Jordanian adults was 573.42 +/- 140.18 N. Those with a short face had the highest MBF (679.60 +/- 117.46 N) while the long-face types had the lowest MBF (453.57 +/- 98.30 N; P < 0.001). The average MBF was 599.02 +/- 145.91 in males and 546.97 +/- 131.18 in females (P = 0.149). No gender differences were observed. The average MBF was higher in patients with premature contacts than those without, while it did not differ in subjects with different types of functional occlusion or in the presence of parafunctional habits.

Próteses obturadoras para pacientes maxilarectomizados: estado atual da tecnologia e necessidades de aprimoramentos / Obturator prostheses for maxillectomized patients: inventory of the existing technology and the need for improvements

Pacientes portadores de comunicação oronasal necessitam de dispositivo protético obturador, para o restabelecimento da sua função, estética e qualidade de vida perdida, devido à remoção ou ausência da maxila. Esta tecnologia reabilitadora vem se desenvolvendo há alguns séculos, com aprimoramentos das técnicas de confecção e materiais odontológicos que auxiliem na elaboração de obturadores cada vez mais eficientes, principalmente no que se refere a sua adaptação. Esta tecnologia é fortemente dependente tanto do domínio das técnicas laboratoriais, quanto de habilidades específicas na arte da reconstrução da face (manuais, sensitivas e tácitas), pois sua confecção é artesanal, personalizada e individualizada, determinando que a disponibilidade e distribuição dos recursos humanos qualificados para a sua elaboração constituam-se em obstáculo significativo para um acesso mais amplo e equânime. O trabalho em tela teve por objetivo examinar o estado da arte relativo às diferentes técnicas de moldagens e confecção das próteses obturadoras utilizadas no cuidado reabilitador de pacientes maxilarectomizados, buscando subsidiar proposições para o seu aprimoramento. Este estudo teórico-exploratório utilizou dois caminhos metodológicos complementares. O primeiro tomou por base uma revisão de literatura científica nacional e internacional e acadêmica, publicada sob a forma de artigos, teses e dissertações, utilizando as bases bibliográficas MEDLINE, BBO, LILACS, SCIELO, Biblioteca Virtual de Saúde e Colaboração Cochrane, e as bases de dissertações e teses da CAPES – Banco de Teses; Base Thesis e Biblioteca Digital de Teses e Dissertações (BDTD), do Instituto Brasileiro de Informação em Ciência e Tecnologia (IBICT)...

Patients with oral-nasal connection due to the absence or extirpation of themaxilla need a prosthetic obturator for esthetical reasons, to restore function, and to partially regain the lost quality of life. This technology has evolved in the course of many centuries in conjunction with the improvement in manufacturing techniques and odontological materials that play a role in the elaboration and design of more efficient obturators, especially regarding their adaptation. This technology is exceedinglydependent on the mastery of laboratorial methods as well as specific skills in the art of facial reconstruction because its confection is artisanal, personalized, and customized. The existence and distribution of suitable human resources are an evident obstacle to the evenly access to this technology. The aim of this work was toscrutinize the “state of the art” regarding different moulding and manufacturing techniques of prosthetic obturators employed in the rehabilitation process of maxillectomized patients, intending to make a contribution for its improvement. This theoretical-exploratory study used two complementary methodological instruments. One was a broad review of the national and international scientific literature published as articles, doctoral thesis and dissertations, utilizing different bibliographical databases: MEDLINE, BBO, LILACS, SCIELO, Biblioteca Virtual de Saúde (Virtual Health Library), and The Cochrane Collaboration, as well as the doctoral thesis and dissertations included in the CAPES database - Base Thesis andDigital Library of thesis and dissertations, from the Brazilian Institute of Information in Science and Technology...

Using tablet PC's in dental practice research: technology, cost savings, and direct data entry "on the go".

Recent technological developments have greatly simplified data collection, recording, and transfer in studies relying on direct observation or survey methodology, reducing both cost of data collection and the time necessary to prepare data for analysis. The purpose of this communication is to describe how tablet PC computers can be used in data collection, thereby eliminating intermediate data collection steps and chances for error, and thus reducing overall cost. The data collection procedure used to illustrate this technology is a direct observation study of the factors associated with the delivery of preventive services by dentists and hygienists in their daily practice.

Substitutes for human cadaveric bone in maxillofacial rigid fixation research.

OBJECTIVE: Various materials have been used as human bone substitutes in rigid fixation research. We hypothesize that these substitutes behave differently than human cadaveric bone in maxillofacial research. STUDY DESIGN: Screw insertion torque and pull-out strength of titanium maxillofacial self-tapping bone screws (1.0 mm and 2.4 mm outer diameter) were measured in cadaveric mandible and in the following materials: bovine rib, porcine rib, photoelastic epoxy, red oak, and 2 types of synthetic mandibles. Results were tested for statistically significant differences (unpaired t test, P <.05) in comparison with human bone. RESULTS: For 1.0-mm screws, statistically significant differences were found for the synthetic mandibles groups and oak groups for insertion torque and porcine rib for pull-out strength. For 2.4-mm screws, statistically significant differences were found for the porcine rib and oak groups for insertion torque and the bovine rib and epoxy groups for pull-out strength. CONCLUSION: The results suggest that human bone can be simulated in fixation studies with bone substitute materials.

The validity of models.

The ubiquity of biofilm and its classification as a microbial aggregate is discussed. Investigations into any microbial ecological problem operate at four levels: (i) in situ investigations, (ii) the use of microcosms, (iii) experimental model systems, and (iv) mathematical models. Each of these is defined and their use in biofilm research illustrated. It is concluded that all these approaches are valid and that scientific research in general and biofilm research in particular must profit by the use widely different methods if a complete understanding of a system is to be achieved.

The application of ESEM in dental materials research.

OBJECTIVES: To describe the use of environmental scanning electron microscopy (ESEM) to investigate acid etching of enamel and to comment on future applications of ESEM in dental materials research. METHODS: The acid etching of axially fractured specimens of human enamel by a 35% (ortho) phosphoric acid etchant was observed using ESEM. RESULTS: Most of the etching action, as evidence by gaseous bubbling in the etchant film, was observed to occur within 10 s of applying the etchant. High magnification examination of the etched areas revealed distinct etching patterns. CONCLUSION: ESEM may play an important role in developing the understanding and existing knowledge pertaining to dynamic chemical and physical interactions between components of restorative systems and tooth tissue substrates.

A modified device for long term sampling of parotid saliva in various experimental conditions.

A parotid cup has been widely used as an intraoral device for the collection of parotid saliva. However, in long duration sampling, the cup tends to disconnect under circumstances such as mastication, sleep or physical exercise. We have designed a modified device of parotid cup for saliva collection to overcome these unfavorable conditions. The parotid cup was modified by fixing it to the bite-plate appliance which was adjusted individually to the occlusal plane in order to avoid disconnection of the cup under varying conditions. Using this device, we could measure salivary flow rate during mastication, sleep or physical exercise. Additional advantages of this device are that it is easy to make with acrylic resin and is inexpensive. The preliminary study using this device showed that flow rates of unstimulated parotid saliva varied from 0.06 +/- 0.04 ml/min. to 0.16 +/- 0.10 ml/min. (mean +/- s.d) from 7 a.m. to 12 p.m. in 7 subjects. In five subjects, the flow rate of parotid saliva during meal (lunch) was much higher than that of resting on a chair, playing table tennis, or sleeping at night for 6-8 hours. This might be considered due to the stimuli of the meal content. Flow rates of saliva were also examined with various stimuli. The results showed that salty pickled plum > sour lemon juice > 10% ascorbic acid > sweet milky candy > 1% ascorbic acid. These data suggest that our modified device is useful for various experiments in salivary research.