Thesis (M.A.)--University of Tennessee, Knoxville, 2003. / Title from title page screen (viewed Sept. 22, 2003). Thesis advisor: Dr. Richard Jantz. Document formatted into pages (vii, 56 p. : ill.). Vita. Includes bibliographical references (p. 51-55).

Thesis (doctoral)--Ludwig-Maximilians-Universität, Munich, 1932.

Thesis (doctoral)--Ludwig-Maximilians-Universität, Munich, 1932.

The treatment of impacted third molars that have neither symptoms nor disease is controversial. One school of thought is that these teeth should be extracted before they do become symptomatic and/or diseased. A second school of thought advocates retaining these teeth until such time when they show evidence of developing symptoms or disease. The purpose of this review is to present the reasoning behind the two opposing schools of thought. Studies involving both the risks and the benefits of extracting and retaining asymptomatic, disease-free third molars were examined. There are studies to support the proponents of each school of thought. Proponents of removal are of the belief that many asymptomatic and disease-free impacted third molars eventually do become symptomatic and/or diseased, and do so when the patient is older. The morbidity and incidence of complications common to the procedure increase with age, and therefore proponents of removal prefer that surgery be performed at a younger age when the complications are less likely to be as severe or permanent. Those in support of retaining and monitoring these teeth are of the opinion that the status of these asymptomatic and disease-free impacted third molars may never change and therefore never require surgical intervention. They believe the increased complication rate and morbidity experience by some of the older surgical patients do not justify the routine removal of all asymptomatic, disease-free impacted third molars at an early age. Both groups recognize that when surgical intervention is employed, complications such as pain, swelling, alveolar osteitis, periodontal problems, temporomandibular joint disorders, nerve involvement, sinus communication, and financial stress are not uncommon. Ultimately, the clinician must consider the information presented in this review, and combine it with his/her academic knowledge and personal clinical experience to inform the patient of the risks and benefits of both treatment options. That way, the clinician and the patient together can decide the strategy for management of an asymptomatic, disease-free third molar.

O presente trabalho teve como objetivo avaliar a microdureza dentinária da região da furca de molares inferiores, assim como estudar, por meio da MEV, a morfologia da dentina nessa região. Utilizaram-se 10 espécimes, os quais tiveram a coroa seccionada transversalmente ao meio, sendo descartada a porção oclusal. As raízes mesial e distal foram cortadas próximas ao terço cervical, desprezando-se os terços médio e apical. O remanescente dental foi incluído em acrílico de rápida polimerização e cortado longitudinalmente ao meio, obtendo-se duas hemi-secções. Uma foi destinada ao estudo da morfologia, na qual observaram-se as características da dentina e o sentido dos canalículos dentinários. Na outra, realizou-se a análise da microdureza, por meio de aparelho de dureza Knoop, com carga de 10g por 15s. A área de furca foi estabelecida como sendo a região compreendida entre duas retas ortogonais traçadas a partir do ponto de máxima concavidade da superfície externa da bifurcação. A microdureza foi avaliada nas camadas de dentina superficial (próxima ao assoalho), média e interna (mais próxima à concavidade externa da furca), assim como nos três eixos, mesial (paralelo à reta traçada junto à mesial da furca), central (paralela à bissetriz entre as retas) e distal (paralela à reta traçada junto à distal). Realizaram-se cinco medidas para cada eixo, obtendo-se uma média por eixo. As mensurações foram submetidas à análise estatística (oneway ANOVA) ( &alpha;= 0,05). Os resultados mostraram não haver diferença significante (p>0,05) entre a dureza das porções mesial (46,5±6,4), central (47,3±8,1) e distal (49,7±6,5). Em relação às camadas, o teste de Tukey evidenciou diferença significante apenas entre as camadas interna (51,7±2,5) e externa (41,4±2,4) (p<0,05). As imagens da MEV mostraram que os canalículos dentinários assumem trajetória centrípeta em direção à porção interna. Os canalículos dentinários na camada externa apresentam-se amplos e com a luz bastante evidente. Na camada média os canalículos são mais atresiados, ao passo que na interna, a dentina assemelha-se à dentina esclerótica. Conclui-se que a microdureza dentinária na área de furca é uniforme nos 3 eixos. A camada interna é mais dura que a externa. A dentina da região de furca parece ser um tecido bastante mineralizado, tendendo a uma maior calcificação dos canalículos à medida que se aproxima da camada interna. / The aim of this study was to evaluate the dentin microhardness in furcation areas of mandibular molars and to study the dentin morphology in these regions by scanning electron microscopy (SEM). The crows of ten specimens were transversely sectioned and the occlusal portions were discarded. The mesial and distal roots were cut near to the cervical third ignoring the middle and apical thirds. The remaining teeth were included in rapid polymerization acrylic stubs and cut longitudinally resulting in two hemi-sections. One was designed to study the morphology in which was possible to observe characteristics of the dentin and dentinal tubules direction. The other one was used to perform analysis of the microhardness using a Knopp device with load of 10g/15s. The furcation areas were established as the regions between two orthogonal lines drawn from the point of maximum concavity of the outer surface of the bifurcation. Microhardness was measured in the superficial layers of dentin (next to the floor), middle and inner (closest to the concavity of the external furcation), as well as in the three axes: mesial (parallel to the straight line along the mesial furcation), central (parallel to the bisectrix between the lines) and distal (parallel to the line drawn along the distal). Five measurements were performed for each axis yielding an average in each one. The measurements were subjected to statistical analysis (one way - ANOVA) (&alpha; = 0.05). The results showed no significant difference (p> 0,05) between the microhardness of the mesial (46.5±6.4), central (47.3±8.1) and distal portions (49.7±6.5). In relation to the layers, the Tukey test showed significant differences only between the inner (51.7±2.5) and outer (41.4±2.4) layers (p <0.05). The SEM images showed that the dentinal tubules assumes centripetal trajectory toward the inner portion. These ones, in the outer layer, presents larger and more evident. In the middle layer are thinner and in the inner layer the dentin is similar to sclerotic dentin. In this study was possible to observe that the microhardness of dentin in the furcation areas is uniform across to the three axes. The inner layer is harder than the outer. The dentin of the furcation areas appears to be a very mineralized tissue having a bigger calcification as it approaches to the inner layer.

Evidence-based dentistry (EBD), an evolving educational tool that started its rise in the late 1990’s and early 2000’s, is being used more every year in dentistry. EBD combines the most current scientific and clinical evidence with the dentists’ expertise and the patients’ needs and preferences to formulate the best option to treat the patient. Since patients are taking more time to research their oral health issues before seeing their dentists, the dentists and the dental team must be prepared for all types of questions. Having the tools necessary to understand the latest and most significant research allows dental professionals to consistently educate themselves. However, there is no independent committee that handles the current issues facing dentistry. Using the topic of asymptomatic removal of third molars as a framework for EBD education, it can be used to help improve how schools educate their students. It is important that both the dental community and the public understand the scientific literature behind the removal of third molars because the existing practice of removing third molars without adverse symptoms is not statistically supported. Unfortunately, there is not enough evidence in favor of either side of the situation. Major databases, like PubMed, contain very little research on the asymptomatic removal of third molars, and those studies were not done recently. For EBD to be successful in dentistry, it must function in the clinical environment, but initial training in the concepts of EBD must start during pre-doctoral education. The dental practitioner still must rely on his or her own experience, but the patient must also trust his or her dentist. EBD is based on trust because it is based on the trust you have demonstrated through your skills and your usage of all available resources. If the dentist can compile pertinent scientific data and information to share with the patient and make the best decision together, then the use of EBD will be beneficial to the field of dentistry.

published_or_final_version / abstract / Dentistry / Master / Master of Dental Surgery

O presente estudo teve como objetivo analisar, por meio de microtomografia computadorizada, os parâmetros morfológicos das raízes mesiais de molares inferiores, preparados por três sistemas mecanizados: reciprocante (Reciproc - RC), rotatório contínuo (OneShape - OS) e reciprocante/rotatório (Twisted-File Adaptive - TFA), precedidos ou não de pré-alargamento (ProGlider - PG). Foram utilizados trinta molares inferiores, com raiz mesial apresentando ângulo (&ge;25º) e raio de curvatura (&le;2mm) severos e dois canais distintos. Por meio da técnica de amostragem estratificada, os canais foram distribuídos em seis grupos (n=10) conforme protocolo de instrumentação: G1-TFA; G2-RC; G3-OS; G4-PG + TFA; G5 - PG + RC; G6- PG + OS. Após o preparo, foram avaliados os parâmetros bidimensionais (área, perímetro, circularidade, diâmetro maior e menor) nos 5mm apicais e tridimensionais (volume, área de superfície e SMI), bem como o transporte do canal radicular. Os dados obtidos foram analisados estatisticamente por meio do teste ANOVA seguido do complementar de Tukey (&alpha;=0,05). O RC apresentou valores, significantemente, maiores de área, perímetro e diâmetro menor em relação ao TFA (p<0,001), não havendo diferença significante entre os sistemas em relação à circularidade (p=0,056) e diâmetro maior (p=0,477). O aumento do volume do canal proporcionado pelos sistemas RC e OS foram semelhantes entre si (p=0,979) e diferente estatisticamente ao TFA (p<0,001). O aumento da área de superfície promovida pelo RC foi similar ao OS (p=0,254) e diferente estatisticamente ao TFA (p=0,001), não havendo diferença entre os dois últimos sistemas (p=0,075). Os valores de SMI do grupo PG + OS foram significativamente maiores que dos demais grupos (p<0,001). Não houve diferença entre os sistemas em relação ao transporte nos terços apical e médio. Concluiu-se que todos os sistemas avaliados apresentaram alterações morfológicas bi e tridimensionais após o preparo biomecânico. O emprego do sistema ProGlider previamente aos sistemas de instrumentação não influenciou as alterações dos parâmetros avaliados. / The present study aimed to analyze, by computerized microtomography, the morphological parameters of mesial roots of mandibular molars prepared by three mechanized systems: reciprocating (Reciproc - RC), continuous rotating (OneShape - OS) and Twisted - File Adaptive (TFA), preceded or not by pre - enlargement (ProGlider-PG). Thirty teeth were used, with mesial root presenting severe angle (&ge;25º) and a radius of curvature (&le;2mm) and two distinct canals. By means of the stratified sampling technique, the canals were distributed in six groups (n = 10) according to the instrumentation protocol: G1-TFA; G2-RC; G3-OS; G4-PG + TFA; G5 - PG + RC; G6- PG + OS. After preparation, the two-dimensional parameters (area, perimeter, roundness, major and minor diameter) were evaluated in the apical 5mm as well as three-dimensional parameters (volume, surface area and SMI) and root canal transportation. The data were statistically analyzed using the ANOVA test followed by Tukey\'s complement (&alpha; = 0.05). The RC presented significantly larger values of area, perimeter, and minor diameter in relation to the TFA (p<0,001), and there was no significant difference between the systems in relation to the roundness (p=0,056) and major diameter (p=0,477). The increased canal volume provided by the RC and the OS systems were similar to each other (p=0,979) and statistically different from the TFA (p<0,001). The increase of the surface area promoted by the RC was similar to the OS (p=0,254) and statistically different to the TFA (p=0,001), with no difference between the other two systems (p=0,075). The SMI values of the PG + OS group were significantly higher than the other groups (p<0,001). There was no difference between the systems in relation to transport in the apical and middle thirds. It was concluded that all evaluated systems presented bi-dimensional and three-dimensional morphological alterations after biomechanical preparation. The use of the ProGlider system prior to the instrumentation systems did not influence the parameters evaluated.

A odontologia minimamente invasiva sugere que durante a realização de preparos cavitários se remova menor quantidade de substrato dentário sadio associado ao uso de materiais adesivos, com o intuito de oferecer durante o tratamento odontológico menor ansiedade e maior conforto ao paciente. Esse estudo teve por objetivo avaliar os níveis de cortisol salivar da criança durante a remoção seletiva de lesões de cárie utilizando laser de Er:YAG e posterior análise longitudinal das restaurações realizadas. Foram selecionadas crianças entre 7 a 10 anos, que apresentassem duas lesões de cárie ativas em dentina localizadas nas superfícies oclusal e proximal (classe II) de molares decíduos. Os dentes de cada criança foram distribuídos em dois grupos aleatoriamente: 1) Laser de Er:YAG (250mJ/4 Hz) e 2) Método convencional (baixa rotação). A dosagem do hormônio cortisol foi realizada por meio de análise imunoenzimática da saliva em 2 momentos: 7 dias antes dos procedimentos e durante a remoção das lesões de cárie. Foi realizada proteção pulpar indireta utilizando cimento de hidróxido de cálcio e cimento de ionômero de vidro nas cavidades profundas e apenas cimento de ionômero de vidro nas cavidades médias. As cavidades foram preparadas e em seguida restauradas empregando o sistema restaurador Adper Single Bond 2/ Filtek Supreme (3M). Para análise clínica das restaurações, três profissionais calibrados e experientes utilizaram os critérios US Public Health Service modificados e exame fotográfico. Para a análise da réplica da restauração os dentes foram moldados e vazados com resina epóxi. A adaptação marginal foi analisada por MEV. As análises clínica e da réplica foram realizadas nos períodos de 7 dias, 6 e 12 meses após a confecção da restauração. Os dados foram analisados por ANOVA e teste de Tukey (&alpha; = 5%). Os níveis de cortisol foram maiores durante a remoção seletiva de cárie, independentemente do método utilizado (p> 0,05). Após 12 meses, não houve evidência de diferença na retenção, adaptação marginal, descoloração, contorno axial e cárie secundária das restaurações realizadas em cavidades preparadas por ambos os métodos. A análise por MEV revelou que os dentes irradiados com laser apresentaram 10% de fendas na extensão total da restauração. Para os dentes preparados pelo método convencional, 20% das fendas foram encontradas na margem cavosuperfícial. A utilização do laser de Er:YAG não aumentou os níveis de cortisol salivar quando comparado ao método convencional e não influenciou o desempenho clínico de restaurações de classe II, sendo um método alternativo para a remoção de lesões cárie em crianças. / Minimally invasive dentistry suggests that during the preparation of cavity preparations, lesser amount of healthy dental substrate associated with the use of adhesive materials is removed, with the purpose of offering less anxiety and greater patient comfort during dental treatment. This study aimed to evaluate the salivary cortisol levels of the child during the selective removal of cáries lesions using Er:YAG laser and later longitudinal analysis of the restorations performed. Children between 7 and 10 years of age were selected to present two lesions of active cáries in dentin located on the occlusal and proximal surfaces (class II) of decíduous molars. The teeth of each child were distributed in two groups randomly: 1) Er:YAG laser (250mJ / 4 Hz) and 2) Conventional method (low rotation). The dosage of the hormone cortisol was performed by means of immunoenzymatic analysis of the saliva in 2 moments: 7 days before the procedures and during the removal of the cáries lesions. Indirect pulp protection was performed using calcium hydroxide cement and glass ionomer cement in the deep wells and only glass ionomer cement in the medium wells. The wells were prepared and then restored using the Adper Single Bond 2 / Filtek Supreme (3M) restorative system. For clinical analysis of the restorations, three calibrated and experienced professionals used the modified US Public Health Service criteria and photographic examination. For the analysis of the réplica of the restoration the teeth were cast and cast with epoxy resin. The marginal adaptation was analyzed by SEM. Clínical and réplicate analyzes were performed in the 7 day, 6 and 12 month periods after the restoration. Data were analyzed by ANOVA and Tukey\'s test (&alpha; = 5%). Cortisol levels were higher during the selective removal of cáries, regardless of the method used (p> 0.05). After 12 months, there was no evidence of difference in retention, marginal adaptation, discoloration, axial contour and secondary cáries of restorations performed in wells prepared by both methods. SEM analysis revealed that the laser irradiated teeth presented 10% of the total length of the restoration. For teeth prepared by the conventional method, 20% of the slits were found in the cavosuperficial margin. The use of the Er:YAG laser did not increase the levels of salivary cortisol when compared to the conventional method and did not influence the clínical performance of class II restorations, being an alternative method for the removal of cáries lesions in children.

O objetivo deste estudo foi avaliar, por meio de imagens obtidas a partir da microtomografia computadorizada (micro-ct), a morfologia interna de canais radiculares distais de molares inferiores. Cem imagens de raízes distais de primeiros e segundos molares inferiores foram obtidas com os microtomógrafos (Skyscan 1176 e 1174, Bélgica) utilizando uma resolução de 18.1&#x3BC;m. Após, a reconstrução das imagens foram feitos os modelos 3D com ajuda da ferramenta CTan e CTvol para a visualização e padronização segundo a classificação de Vertucci. Os seguintes parâmetros foram estudados: classificação morfológica, prevalência do canal principal e ramificações, classificação e prevalência de istmos, forma dos canais, diâmetro apical por meio das distâncias mesiodistais e vestibulolinguais e avaliação do volume apical. Para a avaliação do número, forma dos canais e a presença de istmos foi feito um registro de 9 cortes de cada imagem desde 1,0 até 5,0 mm apicais, considerando 0,5 mm aquém do comprimento real do canal. Para fazer a mensuração do diâmetro mesiodistal e vestibulolingual foi alinhada cada imagem por meio do programa DataViewer e depois foram feitas as anotações das medidas dos canais nos 5,0 mm apicais. O volume apical foi calculado de acordo com a ferramenta 3D Analysis do software CTan. Os resultados foram submetidos ao análise descritiva com o cálculo da porcentagem de ocorrência. Os resultados mostraram que a morfologia do canal mais prevalente foi a tipo I de Vertucci (76%), seguida do tipo V de Vertucci (11%). A forma do canal mais comum foi a circular de 1,0 a 3,5 mm, seguido pela oval de 4,0 a 5,0 mm. A presença de um canal único foi a mais prevalente nos níveis de 1,0 a 5,0 mm. O istmo mais observado foi o do tipo I de Hsu & Kim (86%) no nivel de 1,0 mm, seguido do tipo 5 (39%) a 5,0 mm. Na mensuração das distâncias, a vestibulolingual foi maior que a mesiodistal e o volume aumentou de apical para cervical. Conclui-se que nos canais distais a classificação de Vertucci mais comum foi a tipo I, seguida do tipo V; a presença de um canal único foi o mais prevalente tanto nos níveis de 1,0 como 5,0 mm; quanto a forma do canal, a circular foi a mais predominante desde 1,0 a 3,5 mm (65%), seguida pela forma oval em 4,0 a 5,0 mm (40%); a forma achatada foi a menos prevalente em todos os níveis. A presença de istmos mais observada foi a do tipo I, nos níveis de 1,0 a 5,0 mm. As medidas das distâncias vestibulo-linguais foram maiores em todos os níveis da raiz comparadas com as medidas mesio-distais, e o volume aumentou de apical para cervical. / The objective of this study to evaluate by means of images obtained from computed microtomography (micro-ct), the morphology of the distal root canals of mandibular molars. One hundred images of distal roots of first and second lower molars were obtained with the microtomography (Skyscan 1176 and 1174, Belgium) using a resolution of 18.1 &#x3BC;m. After the reconstruction of the images were analyzed with CTan and CTvol to viewing and standardization according to the classification of Vertucci. The following parameters were evaluated: morphological classification, prevalence the principal canals and ramifications, classification and prevalence isthmus, shape of the canals, through apical diameter mesio-distal and bucco-lingual interval and apical volume. For evaluation of the number, shape of the canals and the presence of isthmus were searched 9 sections of each image from apical 1.0 to 5.0 mm, 0.5 mm before the canals length. To measure mesio-distal and bucco-lingual diameter each image ranged up through DataViewer and then made notations of measurements of the canals in the apical 5.0 mm. The apical volume was calculated in according to the 3D Analysis. The results were subjected to descriptive analysis with the calculation of the percentage of occurrence. The results showed that the morphology the most prevalent was canal type I the Vertucci (76%), followed by type V the Vertucci (11%). The most common canal shape was circular 1.0 to 3.5 mm, followed by the oval in 4.0 mm to 5.0 mm. The presence of a single canal was the most prevalent in levels of 1.0 to 5.0 mm. The isthmus was the most frequently observed type I of the Hsu & Kim (86%) in the level of 1.0 mm, followed by type V (39%) to 5.0 mm. In the measurements of distances, the bucco-lingual was greater than the mesio- distal and volume increased from apical to cervical. The most common Vertuccis classification of the distal canal was the type I, followed by type V; the presence of a single canal was the most prevalent in the levels of 1.0 to 5.0 mm; in the shape of canal, the circular shape was the most common from 1.0 to 3.5 mm (65%), followed by oval shape at 4.0 to 5.0 mm (40%), the flattened shape was less frequent in all levels. The presence of isthmuses most observed was the type I, at levels of 1.0 to 5.0 mm. The measures of bucco-lingual interval were greater at all levels of the root compared to mesio-distal measures, and the volume increased from apical to cervical.