In vitro study of the pulp chamber temperature rise during light-activated bleaching

This study evaluated in vitro the pulp chamber temperature rise induced by the light-activated dental bleaching technique using different light sources. The root portions of 78 extracted sound human mandibular incisors were sectioned approximately 2 mm below the cementoenamel junction. The root cavities of the crowns were enlarged to facilitate the correct placing of the sensor into the pulp chamber. Half of specimens (n=39) was assigned to receive a 35% hydrogen peroxide gel on the buccal surface and the other halt (n=39) not to receive the bleaching agent. Three groups (n=13) were formed for each condition (bleach or no bleach) according to the use of 3 light sources recommended for dental bleaching: a light-emitting diode (LED)laser system, a LED unit and a conventional halogen light. The light sources were positioned perpendicular to the buccal surface at a distance of 5 mm and activated during 30 s. The differences between the initial and the highest temperature readings for each specimen were obtained, and, from the temperature changes, the means for each specimen and each group were calculated. The values of temperature rise were compared using Kruskal-Wallis test at 1% significance level. Temperature rise varied significantly depending on the light-curing unit, with statistically significant differences (p<0.01) among the groups. When the bleaching agent was not applied, the halogen light induced the highest temperature rise (2.38±0.66ºC). The LED unit produced the lowest temperature increase (0.29±0.13ºC); but there was no significant difference between LED unit and LED-laser system (0.35±0.15ºC) (p>0.01). When the bleaching agent was applied, there were significant differences among groups (p<0.01): halogen light induced the highest temperature rise (1.41±0.64ºC), and LED-laser system the lowest (0.33±0.12ºC); however, there was no difference between LED-laser system and LED unit (0.44±0.11ºC). LED and LED-laser system did not differ significantly from each other regardless the temperature rise occurred with or without bleaching agent application. It may be concluded that during light-activated tooth bleaching, with or without the bleaching agent, halogen light promoted higher pulp chamber temperature rise than LED unit and LED-laser system. The tested light-curing units provided increases in the pulp chamber temperature that were compatible with pulpal health

Evaluation of the low intensity laser and ultrasound therapies in the temporomandibular disorder treatment and quality of life

Os objetivos desse estudo foram avaliar a terapia a laser de baixa intensidade (LILT) e o ultrassom, no tratamento da disfunção temporomandibular (DTM) e o impacto da disfunção e das terapias na qualidade de vida dos pacientes. Trinta pacientes foram triados no Serviço de Oclusão e Disfunção da Articulação Temporomandibular da Faculdade de Odontologia de Ribeirão Preto da Universidade de São Paulo (SODAT/FORP-USP) (RDC/DTM). Os pacientes foram pareados quanto ao grau de disfunção e distribuídos aleatoriamente entre três grupos de avaliação: o Grupo I (LILT), o Grupo II (ultrassom) e o Grupo III (não recebeu qualquer terapia). Três pacientes do Grupo III desistiram durante a pesquisa e, portanto, o grupo controle permaneceu com sete pacientes. O LILT (60mW, 60 segundos, 90J/cm²) foi aplicado por ponto da articulação temporomandibular (ATM) de forma pontual e de modo contínuo sobre cinco pontos: lateral da posição condilar (PL), superior da posição condilar (PS), anterior da posição condilar (PA), posterior da posição condilar (PP) e póstero inferior da posição condilar (PI). Com a potência de 60mW foi aplicado por 40 segundos e dose de 60,0 J/cm², por ponto dos músculos masseter superficial (terços superior, médio e inferior) e feixe anterior do músculo temporal. O ultrassom a uma potência de 0,8W/cm² foi aplicado por oito minutos na região da ATM e nos músculos masseter superficial e temporal anterior em movimentos circulares e em modo contínuo. As aplicações foram realizadas duas vezes por semana, no total de oito sessões. As avaliações e mensurações foram realizadas em três tempos; avaliação inicial (pré-tratamento), avaliação pós-terapia e após 30 dias do término das terapias. Os parâmetros de avaliação foram o Índice Craniomandibular (ICM), Índice OHIP-14 para qualidade de vida, dor subjetiva na escala analógica visual (VAS), dor à pressão (algômetro digital), movimentos mandibulares lateralidade esquerda, direita e protrusão (paquímetro digital). Pode-se concluir que as terapias LILT e o ultrassom, foram igualmente eficazes no tratamento da DTM e na melhora da qualidade de vida dos pacientes. A correlação entre DTM e o impacto na qualidade de vida pode ser demonstrada neste estudo.The purpose of this study was to evaluate the low intensity laser therapy (LILT) and ultrasound, in the temporomandibular disorder (TMD) treatment and the TMD and the therapies impacts on quality of life. Thirty patients were selected in the Oclusão e Disfunção da Articulação Temporomandibular service, Faculdade de Odontologia de Ribeirão Preto, Universidade de São Paulo (SODAT/FORP-USP) (RDC/TMD). This study was performed using a random research design. The patients were divided in three groups of evaluation: Group I (LILT), Group II (ultrasound) and Group III (did not receive any therapy). Three patients of Group III had given up during the research and, therefore, the group control remained with seven patients. The LILT (60mW, 60 seconds, 90J/cm²) was applied precisely and continuously into Five points of the temporomandibular joint (TMJ) area: lateral point (PL), superior point (PS), anterior point (PA), posterior point (PP), and posterior-inferior point (PI) of the condylar position. With the power of 60mW it was applied per 40 seconds and 60,0J/cm², per point to masseter (superior, medium and inferior) and anterior temporalis muscles. Ultrasound to a power of 0,8W/cm² was applied per eight minutes in TMJ region and the muscles (masseter and anterior temporalis) with circular movements and continuous way. The applications were performed twice per week, for a total of eight sessions. Data were obtained three times: before treatment, shortly after the eighth session, and 30 days after the therapies. The evaluation parameters had been the Craniomandibular Index (CMI), Index OHIP-14 for quality of life, subjective pain in the visual analogue scale (VAS), mandibular pain to the pressure (digital algometric), movements - left, right and protrusion were employed. It can be concluded that the LILT and ultrasound had been equally efficient in the treatment of the TMD and in the improvement of the quality of life. A correlation between TMD and impact on quality of life was demonstrated

Low Intensity Laser Therapy in Temporomandibular Disorder: a Phase II Double-Blind Study

The purpose of this study was to evaluate the analgesic effect of Low Intensity Laser Therapy (LILT) and its influence on masticatory efficiency in patients with temporomandibular dysfunction (TMD). This study was performed using a random, placebo-controlled, and double-blind research design. Fourteen patients were selected and divided into two groups (active and placebo). Infrared laser (780 nm, 70 mw, 60s, 105J/cm(2)) was applied precisely and continuously into five points of the temporomandibular joint (TMJ) area: lateral point (LP), superior point (SP), anterior point (AP), posterior point (PP), and posterior-inferior point (PIP) of the condylar position. This was performed twice per week, for a total of eight sessions, To ensure a double-blind study, two identical probes supplied by the manufacturer were used: one for the active laser and one for the inactive placebo laser. They were marked with different letters (A and B) by a clinician who did not perform the applications. A Visual Analogue Scale (VAS) and a colorimetric capsule method were employed. Data were obtained three times: before treatment (Ev1), shortly after the eighth session (Ev2), and 30 days after the first application (Ev3). Statistical tests revealed significant differences at one percent (1%) likelihood, which implies that superiority of the active group offered considerable TMJ pain improvement. Both groups presented similar masticatory behavior, and no statistical differences were found. With regard to the evaluation session, Ev2 presented the lowest symptoms and highest masticatory efficiency throughout therapy. Therefore, low intensity laser application is effective in reducing TMD symptoms, and has influence over masticatory efficiency [Ev2 (0.2423) and Ev3 (0.2043), observed in the interaction Evaluations x Probes for effective dosage].CNPq - Conselho Nacional de Desenvolvimento Cientifico e Tecnologico - Brazi

Evaluation of Low Intensity Laser Therapy In Myofascial Pain Syndrome

Limited studies have demonstrated that low intensity laser therapy (LILT) may have a therapeutic effect on the treatment of myofascial pain syndrome (MPS). Sixty (60) patients with MPS and having one active trigger point in the anterior masseter and anterior temporal muscles were selected and assigned randomly to six groups (n=10): Groups I to III were treated with GaAIAS (780 nm) laser, applied in continuous mode and in a meticulous way, twice a week, for four weeks. Energy was set to 25 J/cm(2), 60 J/cm2 and 105 J/cm2, respectively. Groups IV to VI were treated with placebo applications, simulating the same parameters as the treated groups. Pain scores were assessed just before, then immediately after the fourth application, immediately after the eighth application, at 15 days and one month following treatment. A significant pain reduction was observed over time (p<0.001). The analgesic effect of the LILT was similar to the placebo groups. Using the parameters described in this experiment, LILT was effective in reducing pain experienced by patients with myofascial pain syndrome. Thus, it was not possible to establish a treatment protocol. Analyzing the analgesic effect of LILT suggests it as a possible treatment of MPS and may help to establish a clinical protocol for this therapeutic modality

Characteristics of TMD noise analyzed by electrovibratography

Studying joint noise is an important parameter for diagnosing temporomandibular dysfunction. In this study, eight groups (n=9) were formed according to joint dysfunction classification, provided by employing vibration analysis equipment. Parameters for analyzing joint noise were: total vibration energy, peak amplitude, and peak frequency. Mouth opening range was also analyzed. Statistical analysis results for each parameter were significant at 1 %. Each analyzed group presented different noise characteristics. This allowed for inclusion of the groups within a determined value category. The patient group with normal condyle/disk relationship always presented the lowest values. The type of joint noise was characterized by analyzing total integral noise, peak amplitude, peak frequency, and mouth opening. Analyzing joint noise using electrovibratography suggests the type of joint dysfunction and may help to establish a diagnosis, as well as a treatment plan