Influence of dental crown topography on fracture resistance of premolars with MOD preparation and subjected to different restorative protocols.

To evaluate whether dental crown topography influences the fracture resistance of premolars treated endodontically and with MOD preparation subjected to different restorative protocols. Sixty-four human premolars with one or two roots in equal numerical proportions (n) were selected and randomly divided into four groups (n = 8): (S = single-rooted; D = double-rooted) SS: sound single-rooted; SNR: endodontics (E) + MOD cavity preparation; SR: E + MOD + resin restoration (RS); SP: E + MOD + RS + horizontal zirconia post (ZP); DS: sound double-rooted; DNR: E + MOD; DR: E + MOD + RS; and DP: E + MOD + RS + ZP. After allocation to the groups, the samples were thermocycled and then subjected to the fracture resistance test. Failures after the fracture test were classified as irreparable (with pulp floor fracture) or reparable (without pulp floor fracture). Data were analysed using one-way anova and the Tukey test (α = 0.05). Single-rooted premolars were more resistant to fracture than double-rooted premolars. The restorative treatment using a horizontally transfixed zirconia post improved fracture resistance, resembling that of a healthy tooth.

Análise da eficácia de dentifrícios clareadores e seus efeitos na superfície dental: um estudo in vitro / Analysis of the effectiveness of whitening dentifrices and their effects on the dental surface: an in vitro study

O clareamento dos dentes pode ser realizado de várias maneiras, em consultório, no âmbito caseiro ou com a utilização de produtos OTC (Over-the-Counter). Dentre esses produtos, existem os dentifrícios clareadores que prometem clarear e prevenir o manchamento dentário. Objetivos: (1) Investigar o potencial clareador e abrasivo de diferentes dentifrícios no esmalte; e (2) avaliar o efeito do dentifrício Oral-B 3D White Perfection® (Oral-B) na prevenção do escurecimento. Materiais e Métodos: Amostras de esmalte bovino foram pigmentadas e escovadas por 14 dias com água (controle negativo) ou com diferentes produtos: Colgate Total 12® (controle), Oral-B, Sensodyne Branqueador Extra Fresh® (Sensodyne) ou Colgate Luminous White Advanced® (Colgate). Oral-B foi testado antes e após pigmentação. As amostras foram avaliadas quanto à cor (espectrofotômetro) e rugosidade superficial (rugosímetro). Para cálculo de alteração de cor (ΔDE00) se utilizou o sistema CIEDE2000. Os dados foram analisados com os testes Kruskal-Wallis, SNK e Mann-Whitney (α=5%). Resultados: O controle negativo apresentou a menor ΔE00 (p<0,05) e o grupo tratado com Sensodyne resultou nos maiores valores (p<0,05). Quanto à rugosidade superficial, não houve diferença significativa entre os grupos avaliados. O dentifrício Oral-B demonstrou efeito protetivo ao manchamento, resultando em menor alteração de cor (p=0,002). Conclusão: Somente o dentifrício Sensodyne apresentou potencial clareador maior que o dentifrício convencional. A escovação prévia com Oral-B reduziu o manchamento dental, embora não tenha prevenido este totalmente de acontecer. Não foram observadas alterações significativas na rugosidade dos dentes após aplicação dos tratamentos, quando comparado ao controle.

Tooth whitening can be performed at the dental office, at-home or upon the use of OTC (Over-the-Counter) pro-ducts. Among the latter, there are whitening toothpastes that promise to bleach and to prevent tooth staining. Objectives: (1) To investigate the bleaching and abrasive potential of different whitening dentifrices to enamel; and (2) to evaluate the effect of Oral-B 3D White Perfection®(Oral-B) toothpaste in preventing staining. Materials and Methods: Bovine enamel samples were stained and brushed for 14 days with water (negative control) or with different products: Colgate Total 12® (control), Oral-B, Sensodyne Branqueador Extra Fresh® (Sensodyne), and Colgate Luminous White Advanced® (Colgate). Oral-B was also tested before and after staining. The samples were tested by their color (spectrophotometer) and surface roughness (profilometer). Color change (ΔDE00) was cal-culated using the CIEDE2000 color system. The data were analyzed using Kruskal-Wallis, SNK, and Mann-Whitney tests (α=5%). Results: The negative control showed the lowest ΔE00 (p<0.05), whereas the group treated with Sensodyne resulted in the greatest color change (p<0.05). For surface roughness, there was not any significant difference among the groups. The Oral-B toothpaste showed a protective effect against staining, resulting in the lowest color change (p=0,002). Conclusion: Only Sensodyne toothpaste showed higher whitening potential than the conventional toothpaste. By using Oral-B prior staining reduced significantly the intensity of staining, although without the complete prevention of this event. Significant differences were not observed after treatment concerning roughness in comparison to the control.

Fracture resistance of endodontically treated molars restored with horizontal fiberglass posts or indirect techniques.

BACKGROUND: Because of the many possibilities for endodontically restoring the posterior teeth and the high prevalence of restoration failures, this topic continues to be of major concern. A composite resin (CR) restoration reinforced by a horizontal fiberglass post may improve the fracture resistance of endodontically treated teeth. The authors investigated this possibility by comparing the fracture resistance of molars restored with direct techniques with that of molars restored with indirect techniques. METHODS: The authors divided 50 extracted sound third molars into 5 groups: sound teeth, onlay (ON), inlay (IN), direct CR, and transfixed fiberglass post (TFP) plus direct CR. The authors performed standardized mesio-occlusodistal cavity preparations and endodontic treatments. The authors cemented indirect restorations of Lava Ultimate (3M ESPE) adhesively in the ON and IN groups. The authors restored CR group teeth directly with Filtek Z230 XT (3M ESPE). In the TFP group, the authors transfixed 2 fiberglass posts horizontally and restored the teeth directly with CR. Thereafter, the authors submitted the teeth to cyclic fatigue loading with 500,000 cycles at 200 newtons. The authors tested fracture resistance in newtons in a universal testing machine. The authors analyzed data with 1-way analysis of variance and a Tukey test (P < .05). RESULTS: Sound teeth had the highest fracture resistance. ON had the highest recovery of resistance, followed by TFP. CR had the lowest recovery, which was similar to that of IN. CONCLUSIONS: Endodontically treated molars restored with TFP plus CR had fracture resistance similar to those restored with ON, which was higher than that for IN or CR only. PRACTICAL IMPLICATIONS: Horizontal TFPs placed inside a composite restoration had the same performance as did ON restorations.

Clareamento de dentes tratados endodonticamente: uma revisão da literatura / Bleaching of root-filled teeth: a literature review

Na Odontologia contemporânea, a estética sofreu uma valorizaçãosignificativa, ganhando destaque e importância. Nesse contexto, a belezaé influenciada pelo contorno, forma, simetria, alinhamento e,principalmente, pela cor dos dentes. O clareamento de dentes anterioresdesvitalizados escurecidos tem se tornado uma terapia muito requisitada,uma vez que o escurecimento dos dentes é motivo de grande insatisfaçãopor parte dos pacientes. Esta revisão de literatura tem como objetivoanalisar os dados disponíveis na literatura sobre este assunto, uma vezque a associação entre o clareamento interno e a reabsorção radicularexterna cervical é uma questão que ainda gera dúvidas na práticaodontológica. O clareamento interno apresenta resultados esteticamentesatisfatórios, no entanto, apresenta como possível efeito colateral areabsorção radicular cervical externa, que prejudica ou até mesmoinviabiliza a permanência do elemento dental na cavidade bucal. Aetiologia da reabsorção radicular externa relacionada ao clareamento écomplexa, no entanto acredita-se que o agente clareador alcance ostecidos periodontais através dos túbulos dentinários, desnature a dentina,que passa a ser considerada um tecido imunologicamente diferente,sendo reconhecida como um corpo estranho e inicia uma reaçãoinflamatória que resulta na perda localizada de tecido dental. Outralimitação do clareamento de dentes tratados endodonticamente é arecidiva da cor, ainda pouco compreendida. Apesar do clareamento dedentes desvitalizados ter um alto índice de sucesso e de sua naturezaminimamente invasiva, os possíveis efeitos colaterais, tais como areabsorção cervical externa e a recidiva de cor devem ser levados emconsideração no momento de sua indicação.

In modern Dentistry, the smile aesthetics is more valuable every day,gaining importance and prominence. In this context, the beauty isinfluenced by contour, shape, alignment, symmetry and, specially, thecolor of the teeth. The bleaching of anterior endodontically treateddarkened teeth has become a therapy very requested in the clinicalpractice of Dentistry, because stained teeth is of great concern forpatients. This literature review has as objective to analyze the availabledata on this subject, since the association between internal bleaching andexternal cervical root resorption is an issue that still raises questions indental practice. The internal bleaching has aesthetic success, however,this procedure is associated with a risk of external root resorption, whichhinders or even makes impossible the maintenance of the tooth in the oralcavity. The etiology of the external root resorption related to the internalbleaching is complex, however it’s believed that the bleaching chemicalsdiffuse from the pulp chamber through patent dentinal tubules to thesurrounding periodontal tissues, denatures dentin, which starts to beconsidered as a tissue with immunological differences, starting, then, to berecognized as a strange body, resulting in an inflammatory reaction whichresults, then, in the located loss of tissue. Another limitation of the internalbleaching of root-filled teeth is the discoloration. In spite of this procedure’shigh success rate, the results are different from those seen at long-termfollow-up, that is, the color regression is a fact that must be studied andbetter understood.

Reabilitação estética e funcional associada à erosão dentária: relato de caso clínico / Aesthetic and functional rehabilitation of dental erosion: case report

Lesões dentárias não cariosas, como as associadas à erosão ácida, por exemplo, podem provocar prejuízos significativos para a estrutura dentária, gerando hipersensibilidade dentinária, desgaste do esmalte, danos estéticos e perda de dimensão vertical de oclusão. O presente trabalho consiste na apresentação de um caso clínico de reabilitação estética e funcional de uma paciente portadora de erosão dentária, evidenciando uma abordagem clínica integrada, inter-relacionando cirurgia estética periodontal, restabelecimento de dimensão vertical de oclusão, restaurações indiretas de porcelana e restaurações diretas de resina composta. Com o tratamento executado, obteve-se o equilíbrio oclusal desejado, conforto para a paciente e um resultado estético plenamente satisfatório