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r e v p o r t e s t o m a t o l m e d d e n t c i r m a x i l o f a c . 2 0 1 5;5 6(1):63-67 Mandible Cuspid Pathology Impacted tooth a b s t r a c tTransmigration is a rare and special phenomenon in that intraosseous tooth migration takes place, through the midsymphyseal or mid palatine suture. Transmigration typically affects the mandibular canines. These teeth usually remain impacted and asymptomatic but in some cases they ectopically erupt in the midline or next to the contralateral side. Transmigrated teeth can cause neurologic symptoms and pressure resorption of the adjacent teeth roots. A 15-year-old girl was referred to our clinic complaining of pain in the inferior incisives. On intraoral examination, right mandibular deciduous canine was seen to be retained. Panoramic radiograph revealed a horizontally impacted right mandibular permanent canine migrated toward the midline and located below the apices of the incisives. The tooth was surgically removed under general anesthesia. The presence of an overretained mandibular deciduous canine should always be investigated radiographically. © 2015 Sociedade Portuguesa de Estomatologia e Medicina Dentária. Published by Elsevier España, S.L.U. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Transmigração de canino mandibular impactado -Caso Clínico Palavras-chave:Erupção dentária ectópica Mandíbula Canino Patologia Dente impactado r e s u m o A transmigração é um fenómeno raro no qual dentes não erupcionados migram através da linha média maxilar ou mandibular. A transmigração, geralmente, afeta os caninos mandibulares. Normalmente estes dentes permanecem impactados e assintomáticos mas em alguns casos podem erupcionar na linha média ou na região do canino contralateral. Os dentes transmigrados podem originar sintomas tais como dor ou reabsorção das raízes dos dentes adjacentes. Uma menina de 15 anos de idade compareceu a nossa consulta referindo dor nos incisivos inferiores. Ao exame clínico foi possível verificar a presença na arcada do canino mandibular direito decíduo. A radiografia panorâmica revelou que o canino permanente mandibular direito se encontrava impactado numa posição horizontal abaixo

Objectives: Commercial photocurable polymers used in dental additive manufacturing still have mechanical limitations. The incorporation of graphene may provide interesting advantages in this field. This study aimed to evaluate in vitro the effect of adding graphene nanoparticles to a 3D-printed polymethylmethacrylate dental resin in terms of surface roughness, flexural properties, and hardness. Methods: A 3D-printed dental resin (Dental Sand, Harz Lab) was loaded with four different graphene nanoplatelet (Graphenest) concentrations: 0.01wt%, 0.1wt%, 0.25wt%, and 0.5wt%. The neat resin was used as the control group. The surface roughness was measured with a contact profilometer using bar-shaped specimens (50x10x4mm). The flexural strength of specimens (80x10x4mm) from each group was calculated using the 3-point bending test in a Universal Test Machine. Hardness shore D was measured using a manual durometer on round-shaped specimens (12x6mm). Data were evaluated using the Kruskall-Wallis test followed by post-hoc Bonferroni corrected pairwise inter-group comparisons. Statistical significance was set at p<0.05. Results: Graphene improved 3D-printed PMMA resin hardness with statistical significance at a concentration of 0.01wt% (p=0.043). Surface roughness increased with graphene concentrations above 0.01wt%, with statistically significant differences at 0.25wt% (p=0.006) and 0.5wt% (p=0.005) concentrations. Flexural properties worsened with increased graphene concentrations, and these differences were significant in the concentrations of 0.25wt% (p=0.028) and 0.5wt% (p=0.006). Conclusions: The use of graphene as a mechanical reinforcement nanomaterial seems to be viable at low concentrations without prejudice to the surface roughness of a 3D-printed polymethylmethacrylate resin.

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