Effect of short-term increase in occlusal vertical dimension on masticatory muscle electrical activities and pressure-to-pain threshold: A crossover clinical study.

STATEMENT OF PROBLEM: Increasing the occlusal vertical dimension (OVD) is a common procedure in clinical practice. However, few studies have assessed the short-term influence of an increased OVD on the masticatory muscles. PURPOSE: The purpose of this crossover clinical study was to investigate the effect of increased OVD on the electrical activity of masticatory muscles and the pressure-to-pain threshold (PPT) in asymptomatic participants. MATERIAL AND METHODS: Twenty asymptomatic participants (22.7 ±2.39 years of age; 10 men, 10 women) were submitted to an increase in OVD by using interocclusal devices of different thicknesses (3- and 6-mm) for 24 hours. Masticatory muscle activity was assessed with electromyography (EMG), expressed in microvolts (µV), while the participants masticated 2 pieces of latex of different consistency (latex S and H) with and without the device. The PPT was measured with a digital algometer before and after the mastication. The results were assessed by using analysis of variance (ANOVA) and the Tukey honestly significant difference (HSD) test (α=.05). RESULTS: The change of OVD did not significantly affect the electrical activity of the muscles. The latex of hard consistency (latex H) showed higher electrical activity values than the soft texture (latex S). For the working side anterior temporal muscle, a change in the PPT was detected on the day the 6-mm-device was inserted, but for the other muscles, device thickness and latex mastication did not change the PPT. CONCLUSIONS: For a short time, an increase in occlusal vertical dimension did not affect the electrical activity in the masticatory muscles or pressure-to-pain threshold in asymptomatic participants.

Different sealing materials preventing the microbial leakage into the screw-retained implant restorations: an in vitro analysis by DNA checkerboard hybridization.

OBJECTIVES: The aim of this controlled in vitro study was to identify and quantify up to 38 microbial species penetrating through the screw-retained implant prostheses with different sealing materials. MATERIAL AND METHODS: Sixty morse cone implants were restored with single-unit screw-retained prostheses. All the components were randomly divided into five groups (n = 12) according to the proposed materials: (1) polytetrafluoroethylene tape+composite resin; (2) polytetrafluoroethylene tape+gutta-percha; (3) polytetrafluoroethylene tape+light-polymerized provisional composite; (4) cotton pellet+gutta-percha; and (5) cotton pellet+light-polymerized provisional composite. Human saliva was used as contaminant media, and DNA checkerboard hybridization was used to identify and quantify microbial species. RESULTS: Microbial leakage was observed in all groups: M. salivarium, S. pasteuri, P. nigrescens, and P. melaninogenica were the species presenting the highest values of genome count, prevalence, and proportion within the groups. The total microbial mean counts (×105 , ±SD) were as follows: Group 1 (2.81 ± 0.38), Group 2 (3.41 ± 0.38), Group 3 (6.02 ± 1.48), Group 4 (6.40 ± 1.42), and Group 5 (17.45 ± 1.67). Group 5 showed the higher microbial counts (P < 0.001). CONCLUSIONS: Moderate to high counts of pathogenic/nonpathogenic species were detected in the inner parts of implants from all groups. The lowest values of microbial counts were recorded for polytetrafluoroethylene tape associated with composite resin or gutta-percha; cotton pellet associated with light-polymerized provisional composite presented the highest microbial counts.

Microbial diversity of the supra- and subgingival biofilm of healthy individuals after brushing with chlorhexidine- or silver-coated toothbrush bristles.

Nanoparticulate silver has recently been reported as an effective antimicrobial agent. The aim of this clinical study was to investigate the potential changes on the oral microbiota of healthy individuals after controlled brushing with chlorhexidine- or silver-coated toothbrush bristles. Twenty-four healthy participants were enrolled in this investigation and randomly submitted to 3 interventions. All the participants received, in a crossover format, the following toothbrushing interventions: (i) chlorhexidine-coated bristles, (ii) silver-coated bristles, and (iii) conventional toothbrush (Control). All the interventions had a duration of 30 days. The DNA checkerboard hybridization method was used to identify and quantify up to 43 microbial species colonizing the supra- and subgingival biofilm. The supragingival samples presented higher genome counts than the subgingival samples (p < 0.0001). The total genome counts from the Control group showed the highest values, followed by the silver and chlorhexidine groups (p < 0.0001). After 4 weeks of brushing, the silver-coated and chlorhexidine-coated bristles were capable of reducing or maintaining lower levels of the bacterial counts of the putative periodontal pathogens Tanerella forsythia, Treponema denticola, and Porphyromonas gingivalis. Other major periodontal pathogens, such as Prevotella intermedia, Fusobacterium nucleatum, Prevotella nigrescens, and Parvimonas micra, were also detected at lower levels. The toothbrush bristles impregnated with silver nanoparticles reduced the total and individual genome count in the supra- and subgingival biofilm after 4 weeks of brushing. Chlorhexidine was not effective in reducing the total genome counts in both supra- or subgingival biofilm after 4 weeks of brushing. Chlorhexidine reduced the individual genome counts in the supragingival biofilm for most of the target species, including putative periodontal pathogens.

Marginal fit and microbial leakage along the implant-abutment interface of fixed partial prostheses: An in vitro analysis using Checkerboard DNA-DNA hybridization.

STATEMENT OF PROBLEM: Bidirectional leakage through the implant-abutment interface still constitutes a major concern in implant-supported restorations. PURPOSE: The purpose of this in vitro study was to evaluate the marginal fit, before and after loading simulation, of 3-unit fixed partial prostheses supported by external hexagon or Morse cone implants and to identify and quantify up to 43 microbial species penetrating through the implant-abutment interface after loading. MATERIAL AND METHODS: Forty-eight dental implants with external hexagon (EH; n=24) or Morse cone (MC; n=24) connections were investigated. Experimental specimens were made from 2 implants restored with a 3-unit fixed partial prosthesis and divided into 2 groups (n=12) according to platform connection EH or MC. Vertical misfit at the implant-abutment interface was measured before and after loading (150 Ncm during 500,000 cycles at 1.8 Hz). checkerboard DNA-DNA hybridization was used to identify and quantify up to 38 bacterial and 5 Candida species colonizing the internal parts of the implants after loading. Generalized estimating equations were used for statistical analysis (α=.05). RESULTS: The mean values (mm, ±SD) of vertical misfit for EH were 0.0131 ±0.002 before loading and 0.0138 ±0.002 after loading and for MC were 0.0132 ±0.003 before loading and 0.0137 ±0.001 after loading. Twenty-one bacterial species, including periodontal pathogens and C. albicans, were found colonizing the inner surfaces of EH implants after loading. None of the target species were detected in the internal parts of MC implants. CONCLUSIONS: EH implants showed higher microbial counts than MC implants, in which microbial colonization was not found after loading. Detected species included nonpathogens and microorganisms related to periodontal/periimplant diseases. Further studies are needed to evaluate the effect of loading simulation on the marginal misfit of 3-unit fixed partial prostheses supported by EH or MC implants, because no significant differences could be found either before or after loading.

Bacterial adhesion on the titanium and zirconia abutment surfaces.

OBJECTIVE: Microorganisms harboring the oral cavity, mainly those related to periodontal diseases, are the most potential etiologic factor of failure in long-term implant treatment. The material used for abutment components may influence the adhesion and colonization of microbial species. The aim of this in vivo investigation was to evaluate the biofilm formation on machined (MPT) or cast titanium (CPT) and zirconia abutments (Zc). METHODS: Six healthy subjects were enrolled in this randomized crossover clinical investigation. The study was conducted in three phases according to abutment surface evaluated. Each subject used an individual oral splint containing four disks of the same tested substrate, two located in the anterior and two in the posterior region, totalizing 12 specimens for subject. Participants were asked to use the removable intraoral splint during 24 h. DNA checkerboard hybridization method was used to identify and quantify 38 bacterial species colonizing formed biofilm on the abutment substrates. RESULTS: Pathogens and non-pathogens species were found colonizing the three substrates surfaces. Fusobacterium nucleatum, Neisseria mucosa, Porphyromonas aeruginosa, Peptostreptococcus anaerobios, Staphylococcus aureus, Streptococcus gordonii, Streptococcus parasanguinis, and Tanerella forsythia were the only species with no significant differences over the tested materials (P > 0.05). All the other target species presented significant differences sought by Friedman test (P < 0.0001). CONCLUSIONS: There was a significant difference in the total bacterial count between the three groups. CPT presented the higher mean counts, followed by MPT and Zc. CPT group also showed a higher mean incidence of species than MPT and Zc. The anterior or posterior region of disks placement did not show significant differences in relation to bacterial adhesion.

Effectiveness of three antimicrobial mouthrinses on the disinfection of toothbrushes stored in closed containers: a randomized clinical investigation by DNA Checkerboard and Culture.

OBJECTIVES: The aim of this in vivo study was to evaluate the efficacy of three antimicrobial solutions on the disinfection of toothbrushes after storage in closed containers. MATERIALS AND METHODS: Sixteen healthy subjects were enrolled in this randomized cross-over clinical investigation. The study was conducted in four phases, in which mouthrinses (chlorhexidine gluconate-based or cetilpiridinium-based) and sterile tap water (control group) were used to individually store used toothbrushes in closed containers during 7 days of toothbrushing. Five toothbrushes were used as negative control for bacterial colonisation before contact with oral cavity. Conventional culture and DNA Checkerboard hybridization were used to detect bacterial contamination on the toothbrushes. Subsequently, the number of bacterial species on the bristles was estimated by the DNA Checkerboard method. RESULTS: One toothbrush presented bacterial contamination in the negative control test. Both culture and DNA Checkerboard showed positive signals of bacterial contamination in the toothbrushes with no differences in the frequency of detection. The control group showed higher total bacterial counts when compared with the mouthrinse groups. Porphyromonas gingivalis had the highest bacterial count followed by Parvimonas micra. CONCLUSION: Culture and DNA Checkerboard showed positive signals of bacterial contamination. Mouthrinses that contains 0.12% of chlorhexidine gluconate were more effective in reducing bacterial colonisation on the toothbrushes.

Prosthetic platforms in implant dentistry.

The use of implant-supported prosthesis to replace missing teeth became a predictable treatment. Although high success rate has been reported, implant treatment is suitable to complications, failures, and limitations such as peri-implant bone loss after implant loading. Stress evaluation on the bone-abutment-implant interface has been carried out to develop new designs of prosthetic platform and to understand the stress distribution in this interface. Several types of prosthetic platforms are available such as external and internal hexagon, Morse cone connection, and the concept of platform switching. Therefore, this study aimed to critically describe the different options of prosthetic platforms in implant dentistry, by discussing their biomechanical concepts, clinical use, and advantages and disadvantages. It was observed that all types of prosthetic platforms provided high success rate of the implant treatment by following a strict criteria of indication and limitation. In conclusion, a reverse planning of implant treatment is strongly indicated to reduce implant overload, and the use of advanced surgical-prosthetic techniques is required to obtain a long-term success of oral rehabilitations.

Reconstruction of skull defects: currently available materials.

The restoration and recovery of a compromised skull continues to be a challenge to craniofacial surgeons and neurosurgeons. Different operative techniques and implant materials are being used to reconstruct the rigid framework of the skull. However, no currently available materials satisfy all of these criteria. According to this premise, the aim of this study was to report on the currently available materials for the reconstruction of the cranial vault and to describe their main characteristics, advantages, and disadvantages. Although the use of the materials discussed in this study is clearly positive for the reconstruction of skull defects and cranioplasties, there is a need for more complex studies and research into developing these materials to achieve all the ideal prerequisites stipulated by the scientific community and to evaluate their properties and aesthetic and functional results in the long term.

Effect of polymerization methods and thermal cycling on color stability of acrylic resin denture teeth.

STATEMENT OF PROBLEM: Acrylic resin denture teeth are widely used due to the chemical bond to the acrylic resin of the denture base. However, discoloration of acrylic resin denture teeth can be a problem. PURPOSE: The purpose of this study was to investigate the effect of polymerization methods and thermal cycling on the color change of acrylic resin denture teeth. MATERIAL AND METHODS: Ten different brands of acrylic resin denture teeth were evaluated: Art Plus (AP), Biolux (BX), Biotone IPN (BI), Magister (MG), Mondial 6 (MD), Premium 6 (PR), SR Vivodent PE (SR), Trilux (TR), Trubyte Biotone (TB), and Vipi Dent Plus (VP). Each brand was divided into 2 groups (n=12); each group was subjected to 1 of 2 polymerization methods (microwave, 500 W for 3 minutes, or water bath, 74 degrees C for 9 hours). After polymerization, all of the specimens were thermal cycled between 5 degrees C and 55 degrees C with 30-second dwell times for 5000 cycles. The specimen colors were measured with a spectrophotometer, using the CIE L*a*b* system, at baseline (B), after polymerization (P), and after thermal cycling (T). Color differences (DeltaE) were calculated for periods between P and B (PB), T and B (TB), and T and P (TP). A DeltaE of < or =3.3 was considered clinically acceptable. The data were evaluated by 3-way repeated-measures ANOVA and the Tukey HSD test (alpha=.05). RESULTS: The highest DeltaE values were obtained for BI and SR teeth; these were significantly higher than the values obtained for the other brands (P<.05). There was no significant difference between the 2 polymerization methods. There was no significant difference between TB and PB for either polymerization method. CONCLUSIONS: The DeltaE values are within acceptable clinical limits for all brands, for both polymerization methods and different measurement periods.

Effect of occlusion on joint sounds in asymptomatic individuals.

Occlusion is a predisposing factor for Temporomandibular Dysfunctions (TMD) of the joint, whose first sign and/or symptom is usually joint sound. To verify the effect of occlusion on joint sounds, temporomandibular joints (TMJ) were analyzed in 78 asymptomatic individuals with various dental conditions. Electrosonography was used to determine the intensity of the vibration in the temporomandibular joint (TMJ) on opening and closing the mouth. Transducers (piezoelectric accelerometer) were placed on the right and left joints. Results were tabled and analyzed using the Kruskal-Wallis test (a=0.05). It was concluded that TMJ vibration in partly edentulous individuals from Kennedy classes I, II and III is statistically higher than in dentate and fully edentulous subjects.

Microbiome of titanium and zirconia dental implants abutments.

OBJECTIVES: This study employed culture-independent molecular techniques to extend the characterization of the microbial diversity of biofilm associated with either titanium or zirconia implant-abutments, including not-yet-cultivated bacteria species, and to identify and quantify species recovered from peri-implantar/periodontal sulci, supragingival biofilm and the internal parts of implants. Probing depth, clinical attachment level, bleeding on probing, and marginal bone level were also evaluated over time and correlated with biofilm formation. METHODS: Twenty healthy participants were analyzed. DNA-Checkerboard and 16S-rDNA-Pyrosequencing were used to quantify and determine species identity. RESULTS: 161 bacterial taxa representing 12 different phylotypes were found, of which 25% were non-cultivable. Species common to all sites belonged to genera Fusobacterium, Prevotella, Actinomyces, Porphyromonas, Veillonella and Streptococcus. While some species were subject-specific and detected in most sites, other species were site-specific. Moderate to higher levels of unclassified species were found colonizing titanium-related sites. Pathogenic and non-pathogenic species were detected colonizing oral sites in both materials. Titanium-related sites presented the highest total microbial count and higher counts of pathogenic species. CONCLUSIONS: Our results revealed differences regarding microbial diversity and microorganisms counts in oral biofilm associated with titanium or zirconia. The obtained data suggests a possible relation between microbiological findings and clinical outcomes. SIGNIFICANCE: Next-generation methods of detection have provided new insights on complex microbiota colonizing different sites of oral cavity. The present study demonstrates relevant differences in the communities and microbial counts colonizing different tested substrates with consequent significant differences in the clinical-outcomes, suggesting a probably different mechanism for specific bacterial adhesion.

Genomic identification and quantification of microbial species adhering to toothbrush bristles after disinfection: A cross-over study.

PURPOSE: The aim of this clinical investigation was to identify and quantify the microbial species adhering to toothbrush bristles after controlled brushing and storage in different antimicrobial agents. METHODS: Sixteen healthy participants were enrolled in this study and randomly submitted to 4 interventions in a cross-over design: brushing and toothbrush storage in (I) Periogard/(II) Periobio (Chlorhexidine gluconate 0.12%), (III) Cepacol (cetylpyridinium chloride 0.05%) and (IV) distilled water (positive control). Thirty-eight bacterial species including putative pathogens and 5 Candida spp. were assessed by Checkerboard DNA-DNA hybridization. RESULTS: The results of the study have shown a striking reduction of the total microbial counts, including bacteria and Candida spp., on the toothbrush bristles after storage in cetylpyridinium chloride 0.05% (p < 0.0001). Chlorhexidine gluconate 0.12% showed no differences on the total bacterial count when compared to distilled water (p > 0.05). Cetylpyridinium chloride solution also presented the lowest genome counts and frequency of detection for individual target species; distilled water showed the highest individual genome counts (p < 0.05). Potential pathogenic species were recorded in moderate to high levels for chlorhexidine gluconate and distilled water. CONCLUSION: Cetylpyridinium chloride 0.05% was the most effective storage solution in the reduction of total and individual microbial counts, including pathogenic species.

Impact of temperature and time storage on the microbial detection of oral samples by Checkerboard DNA-DNA hybridization method.

PURPOSE: Molecular diagnosis methods have been largely used in epidemiological or clinical studies to detect and quantify microbial species that may colonize the oral cavity in healthy or disease. The preservation of genetic material from samples remains the major challenge to ensure the feasibility of these methodologies. Long-term storage may compromise the final result. The aim of this study was to evaluate the effect of temperature and time storage on the microbial detection of oral samples by Checkerboard DNA-DNA hybridization. METHODS: Saliva and supragingival biofilm were taken from 10 healthy subjects, aliquoted (n=364) and processed according to proposed protocols: immediate processing and processed after 2 or 4 weeks, and 6 or 12 months of storage at 4°C, -20°C and -80°C. RESULTS: Either total or individual microbial counts were recorded in lower values for samples processed after 12 months of storage, irrespective of temperatures tested. Samples stored up to 6 months at cold temperatures showed similar counts to those immediately processed. The microbial incidence was also significantly reduced in samples stored during 12 months in all temperatures. CONCLUSIONS: Temperature and time of oral samples storage have relevant impact in the detection and quantification of bacterial and fungal species by Checkerboard DNA-DNA hybridization method. Samples should be processed immediately after collection or up to 6 months if conserved at cold temperatures to avoid false-negative results.

In vivo evaluation of Candida spp. adhesion on titanium or zirconia abutment surfaces.

OBJECTIVE: Candida spp. have been found colonising implant sites in healthy or diseased subjects. The aim of this in vivo study was to evaluate the Candida spp. adhesion on machined or cast titanium and zirconia (Zc) abutment substrates. DESIGN: Six healthy subjects were enrolled in this randomised crossover clinical investigation. The study was conducted in three phases according to evaluated substratum. Participants were advised to use an intraoral splint containing four discs of the same tested substrate for 24h. Two discs were located in the anterior region and two in the posterior region. DNA checkerboard hybridisation method was used to detect and quantify five different Candida species. Data on the surface roughness and the total area of discs covered by formed biofilm were also provided to correlate the species and biofilm found between different substrates. RESULTS: Zc presented the highest means of surface roughness. Total area of the biofilm covering was not different in the tested groups. Moderate to high levels of target microorganisms were recorded for all the tested substrates. Zc showed the lowest indices, followed by machined pure titanium (MPT) and cast and polished titanium (CPT). Candida albicans and Candida krusei were not detected in the Zc group. The region of disc placement did not show differences in relation to Candida adhesion. CONCLUSIONS: There was a significant difference in the total cell count between the three groups. CPT presented the higher mean counts, followed by MPT and Zc. There was no positive correlation between the cell counts recorded and the surface roughness or total area of formed biofilm.

Oral biofilm formation on the titanium and zirconia substrates.

OBJECTIVE: The aim of this randomized crossover investigation was to assess the biofilm formation on two titanium and one zirconia substrates in relation to the topography and surface roughness of the materials. METHODS: Twenty-four discs specimens for each evaluated material (Machined pure titanium, Cast pure titanium, or Zirconia) were evaluated after oral cavity exposure in six healthy subjects. The study was conducted in 3 phases according to the material evaluated. Each subject was asked to use a removable splint containing 4 disks of the same tested substrate, 2 located in the anterior, and 2 in the posterior region. Participants were asked to use the intraoral splint during 24 h. The total biofilm covering on the discs was evaluated by 1% of neutral red staining. EMV and surface roughness was carried out to correlate with the biofilm found between different substrates. RESULTS: Data showed higher mean roughness values for zirconia (Zc) when compared with titanium specimens (MPT and CPT; P < 0.001). MPT and CPT presented no differences between them (P > 0.05). The mean percentage (%) of covering biofilm on substrates was 84.14 for MPT, 86.22 for CPT and 90.90 for Zc. CONCLUSION: There were no significant differences in the total area of formed biofilm among the tested groups. No correlation was found between surface roughness and the total amount of formed biofilm in the groups.

Effect of occlusal splint thickness on electrical masticatory muscle activity during rest and clenching.

The extent of separation between the maxillary and mandibular teeth in the fabrication of interocclusal splints designed to achieve efficiency and muscle relaxation is controversial and undefined in the literature. Based on this premise, the aim of this study was to evaluate the effect of interocclusal splint thicknesses of 3 and 6 millimeters on the electrical activity of the anterior temporal and masseter muscles during rest and dental clenching. Twenty asymptomatic individuals (10 males and 10 females) were selected using the Research Diagnostic Criteria (RDC). Electromyography (EMG) was performed both with and without the 3- and 6-mm splints using the Bio EMG software package, which recorded values given in microvolts (µV). The results, which were assessed using analysis of variance (ANOVA) to a 5% significance level (p < 0.05), showed increased electrical activity of the masticatory muscles during dental clenching compared with at rest, with greater activity in the masseter muscle. The electrical activity did not differ according to the thickness of the splints or between males and females. We can conclude that both splint thicknesses are effective in treating muscle hyperactivity given their similar clinical behavior for asymptomatic individuals.

Registro do perfil de emergência para mimetização dos dentes naturais na região estética / Emergence profile registration to mimic natural teeth in the esthetic region

Introdução: o tratamento com implantes dentários para a reposição de dentes na região estética exige a utilização de materiais e técncias que permitam o máximo de naturalidade entre a restauração, os dentes vizinhos e to tecido gengival. Dessa forma, torna-se necessário criar o correto perfil de emergência para o dente, assim como a utilização de materiais com alto potencial estético. Objetivo: o objetivo do presente trabalho foi ilustrar, através de um caso clínico, a utilização de moldagem para a correta cópia do perfil de emergência do dente e sua transferência para o modelo de trabalho, tornando possível a confecção de uma restauração totalmente cerâmica, perfeitamente integrada ao tecido gengival. Caso clínico: paciente de 30 anos, procurou a clínica de prótese dentária com desejo de melhorar a estética dos dentes. Após diagnóstico e planejamento, foram confeccionadas 2 coroas totalmente cerâmcias sobre os dentes 12 e 21, e confecção de 1 coroa cerâmica sobre um pilar de zircônia após o estabelecimento e registro do perfil de emrgência do dente 11. Conclusão: após a conclusão do trtamento, observou-se naturalidade, estética e perfeita integração entre as restaurações, os dentes remanescentes e o tecido gengival.

Introduction: The treatment with dental implants for tooth replacement in esthetic regions requires the use of esthetic materials and techniques that allow natural restorations among the neighboring teeth and gingival tissue. Thus, it is necessary to create the proper emergence profile for the tooth, as well as the use of materials with high esthetic potential. Objective: The objective of this study was to illustrate through a clinical case using a impression technique for the correct copy of the emergence profile of the tooth, and its transfer to the working model, making possible the creation of an all-ceramic restoration perfectly integrated with the gingival tissue. Clinical case: The 30 years-old patient went to the dental clinic with the desire to improve the esthetics of her teeth. After diagnosis and planning were made two all-ceramic crowns on right lateral incisor (#12) and left central incisor (#21). Furthermore, it was made a ceramic crown on a zirconia based abutment after the creation and registration of the emergency profile of the right central incisor (#11). Conclusion: After finished the treatment it was observed naturalness, esthetics and seamless integration between the restorations, the remaining teeth and gingival tissue.

Effect of occlusal splint thickness on electrical masticatory muscle activity during rest and clenching

The extent of separation between the maxillary and mandibular teeth in the fabrication of interocclusal splints designed to achieve efficiency and muscle relaxation is controversial and undefined in the literature. Based on this premise, the aim of this study was to evaluate the effect of interocclusal splint thicknesses of 3 and 6 millimeters on the electrical activity of the anterior temporal and masseter muscles during rest and dental clenching. Twenty asymptomatic individuals (10 males and 10 females) were selected using the Research Diagnostic Criteria (RDC). Electromyography (EMG) was performed both with and without the 3- and 6-mm splints using the Bio EMG software package, which recorded values given in microvolts (µV). The results, which were assessed using analysis of variance (ANOVA) to a 5 percent significance level (p < 0.05), showed increased electrical activity of the masticatory muscles during dental clenching compared with at rest, with greater activity in the masseter muscle. The electrical activity did not differ according to the thickness of the splints or between males and females. We can conclude that both splint thicknesses are effective in treating muscle hyperactivity given their similar clinical behavior for asymptomatic individuals.

Sintomas auditivos e desordens temporomandibulares / Hearing symptoms and temporomandibular disorders

Introdução: Uma variedade de hipóteses tem sido propostas para esclarecer a associação entre desordens temporomandibulares e sintomas auditivos, entre elas as múltiplas possibilidades anatômicas e/ou neurológicas que, a partir de uma disfunção muscular ou articular, podem acarretar tais sintomas. Objetivo: O propósito do presente estudo é discutir, através de uma revisão sistemática de literatura, a inter-relação entre os sintomas auditivos e as desordens temporomandibulares. Material e Método: Foram consultados os indexadores Medline/PubMed, ISI e Scielo, no período de 1918 a 2008. Os termos relacionados para a pesquisa foram: “temporomandibular disorders”, “signs and symptoms of temporomandibular disorders”, “otologic symptoms” e “aural symptoms”, onde 19 artigos foram incluídos através dos critérios pré-selecionados para a confecção de uma metaanálise. Resultados: Segundo os dados encontrados, os sintomas auditivos mais frequentemente relacionados com desordens temporomandibulares foram otalgia e zumbido, seguido de vertigem e perda auditiva, respectivamente. Conclusões: Torna-se evidente a correlação entre os sintomas auditivos e as desordens temporomandibulares, entretanto há a necessidade de pesquisas clínico-científicas mais complexas para comprovarem as específicas relações causa-efeito entre ambos

Introduction: A variety of hypotheses have been proposed to explain the association between temporomandibular disorders and hearing symptoms, including the many anatomical and/or neurological ways, as of a muscle or joint dysfunction, can cause such symptoms. Objective: The purpose of this study is to discuss, through a systematic review of literature, the interrelation between hearing symptoms and temporomandibular disorders. Material and Methods: We consulted the Medline/PubMed, ISI and Scielo in the period 1918 to 2008. The terms related to the research were: “temporomandibular disorders”, “signs and symptoms of temporomandibular disorders”, “otologic symptoms” and “aural symptoms”, where 19 papers were included using the pre-selected criteria for the manufacture of a meta-analysis. Results: According to the findings, the hearing symptoms most often associated with temporomandibular disorders were otalgia and tinnitus, followed by vertigo and hearing loss, respectively. Conclusions: It’s clear the correlation between hearing symptoms and temporomandibular disorders, however there is a need clinical and scientific research more complex to prove the specific cause-effect relationships between them

Variação da temperatura superficial dos músculos masseter e temporal anterior durante o apertamento dental voluntário com placas interoclusais maxilares de duas diferentes espessuras / Variation of surface temperature on superficial masseter and anterior temporal muscles during voluntary teeth clenching with maxillary splints of two different thicknesses

A atividade muscular tem sido estudada de maneira indireta pela análise da variação da temperatura superficial cutânea sobre os músculos mastigatórios. Essas mensurações podem representar uma ferramenta valiosa na avaliação clínica da atividade e do progresso das desordens temporomandibulares, bem como no acompanhamento do protocolo terapêutico adotado, justificando sua utilização para verificar alterações patológicas na circulação sanguínea e/ou atividade metabólica nos tecidos abaixo da pele, como os músculos mastigatórios. Em vista disso, o objetivo do presente estudo foi verificar o efeito da espessura da placa interoclusal sobre a variação da temperatura superficial dos músculos temporal anterior e masseter, durante o repouso e o apertamento dental, considerando-se a condição assintomática de 20 indivíduos (10 do gênero masculino e 10 do gênero feminino) selecionados através do questionário Research Diagnostic Criteria (RDC). A temperatura em graus Celsius (ºC) da superfície dos músculos masseter e temporal anterior foi medida com o auxílio de um termômetro digital, com um sistema de leitura por irradiação infravermelha. A temperatura superficial dos músculos temporal anterior e masseter apresentou redução significativa diante do apertamento dental em relação à posição de repouso mandibular. Entretanto, não houve diferenças significantes entre as condições com e sem placa interoclusal, bem como entre as distintas espessuras de placas interoclusais analisadas. Adicionalmente, os músculos mastigatórios apresentaram uma considerável semelhança entre os lados, sem haver também distinções significantes entre o gênero masculino e o feminino.

Muscle activity has been studied indirectly through analyses of temperature variation in skin surface temperature on the masticatory muscles. These procedure may be an important tool for clinical evaluation and assessment of the evolution of temporomandibular disorders, as well as monitoring the adopted protocol. Thus, its utilization for identified pathological alterations on blood circulation and/or on metabolic activity in subcutaneous tissues, such as the masticatory muscles, is justified. The aim of this study was to investigate the effect of occlusal splintsÆ thickness on the variation of surface temperature of the anterior temporal and masseter muscles during rest and clenching. It were analyzed 20 asymptomatic subjects (10 males and 10 females) selected through the Research Diagnostic Criteria (RDC) questionnaire. Temperature expressed in degrees Celsius (ºC) was measured on the surface of both muscles measured with the aid of a digital thermometer with an infrared radiation reading system. The surface temperature of the anterior temporal and masseter muscles presented significant reduction during teeth clenching in relation to the mandibular rest position. However, there were no significant differences between conditions with and without occlusal splint or between the different thicknesses of splints analyzed. Masticatory muscles showed a considerable similar behavior for both sides, and no significant distinctions were observed between male and female patients.