RESUMEN
Background: To analyze through finite element analysis the stress distribution in peri-implant bone tissues, implants, and prosthetic components induced by the socket shield (SS) technique in comparison to other techniques used to treat tooth loss. Materials and Methods: A three-dimensional model of a superior central incisor crown supported by implant was modeled and three different placement conditions were simulated: SS - 2.0-mm-thick root dentin fragment positioned between the alveolar buccal wall and implant; heterologous bone graft (HBG) - bovine bone graft positioned the alveolar buccal wall and implant; and control (C) - implant fully placed in bone tissue of a healed alveolus. The model was restricted at the lateral surfaces of the bone tissue and the following loads were simulated: Both oblique (45°) loads of 100 N on the lingual surface of the crown (maximal habitual intercuspation) and 25.5 N on the incisal edge of the crown (tooth contact during mandibular protrusion) were simultaneously applied. Tensile stress, shear stress, compression, and displacement were analyzed in the cortical bone, trabecular bone, dentin root fragment, and bone graft; while equivalent von Mises stresses were quantified in the implant and prosthetic components. Results: Stress values of SS and HBG in the bone tissues were higher than C, while slight differences within models were observed for dentin root fragment, bone graft, implant, and prosthetic components. Conclusions: The SS technique presented the highest stress concentration in the peri-implant tissues.
RESUMEN
OBJECTIVE: To evaluate facial profile changes promoted by polymethyl methacrylate (PMMA) cement graft to reduce excessive gingival display due to hyperactivity of the elevator muscles of the upper lip during smiling. METHODS: Eleven patients (all females, age range: 20 to 43 years) presenting gingival smile that were treated with PMMA cement grafts in a private clinic were selected for this retrospective study. Three angular and ten linear cephalometric facial profile measurements were performed preoperatively (baseline, T1) and at least 6 months postoperatively (T2). Differences between T1 and T2 were verified by Wilcoxon test, and the correlation between the thickness of the graft and facial profile changes was statistically evaluated by Spearman's Coefficient test. The significance level was set at p< 0.05. RESULTS: The nasolabial angle (p= 0.03) and the labial component of the nasolabial angle showed statistically significant differences (p= 0.04), with higher values in T2. No correlations were found between the graft thickness and the statistically significant facial profile changes (p> 0.05). CONCLUSIONS: The PMMA bone cement graft projected the upper lip forward, thereby increasing the nasolabial angle without affecting the nasal component. No correlations between the graft thickness and the facial profile changes were detected.
Asunto(s)
Cementos para Huesos , Sonrisa , Adulto , Cefalometría , Femenino , Encía , Humanos , Labio , Estudios Retrospectivos , Adulto JovenRESUMEN
O sorriso gengival é uma causa comum de insatisfação entre os pacientes. Em alguns casos, o lábio superior pode não ter suporte ósseo adequado na dinâmica do sorriso, encurtando-se ao se alojar em uma depressão óssea no fundo de vestíbulo, em sorrisos mais amplos ou mesmo durante a fala. Este artigo descreve um tratamento inovador, indicado em casos de falta de suporte labial causado por depressão óssea no fundo de vestíbulo: o aumento estético de coroa clínica e reposicionamento labial com cimento ortopédico...
Gingival smile is a common reason of disatisfaction between patients. In some cases, the upper lip may not have adequate bone support when smiling, and gets shrinked as it lodges in the sub-nasal bone depression, whether in an open smile or when the patient is speaking. This paper describes a novel treatment indicated for cases of lacking support of the upper lip caused by a sub-nasal bone depression: clinical crown lengthening associated with lip repositioning using bone cement...
Asunto(s)
Humanos , Femenino , Adulto Joven , Alargamiento de Corona , Estética Dental , Encía , SonrisaRESUMEN
BACKGROUND: Titanium (Ti) is widely proven to enhance bone contact and growth on its surface. It is expected that bone defects could benefit from Ti to promote healing and to increase strength of the implanted area. PURPOSE: The present study aimed at comparing the potential of porous Ti sponge rods with synthetic hydroxyapatite (HA) for the healing of bone defects in a canine model. MATERIAL AND METHODS: Six mongrel dogs were submitted to three trephined osteotomies of 6.0 x 4.0 mm in one humerus and after 2 months another three osteotomies were performed in the contralateral humerus. A total of 36 defects were randomly filled either with Ti foam, particulate HA, or coagulum (control). The six animals were killed 4 months after the first surgery for histological and histometrical analysis. RESULTS: The Ti-foam surface was frequently found in intimate contact with new bone especially at the defect walls. Control sites showed higher amounts of newly formed bone at 2 months - Ti (p = 0.000) and HA (p = 0.009) - and 4 months when compared with Ti (p = 0.001). Differently from HA, the Ti foam was densely distributed across the defect area which rendered less space for bone growth in the latter's sites. The use of Ti foams or HA resulted in similar amounts of bone formation in both time intervals. Nevertheless, the presence of a Ti-foam rod preserved defect's marginal bone height as compared with control groups. Also, the Ti-foam group showed a more mature bone pattern at 4 months than HA sites. CONCLUSION: The Ti foam exhibited good biocompatibility, and its application resulted in improved maintenance of bone height compared with control sites. The Ti foam in a rod design exhibited bone ingrowth properties suitable for further exploration in other experimental situations.
Asunto(s)
Materiales Biocompatibles/química , Sustitutos de Huesos/uso terapéutico , Durapatita/uso terapéutico , Húmero/cirugía , Osteogénesis/fisiología , Osteotomía/métodos , Titanio/química , Animales , Enfermedades Óseas/patología , Enfermedades Óseas/cirugía , Médula Ósea/patología , Colorantes , Modelos Animales de Enfermedad , Perros , Húmero/patología , Masculino , Pironina , Distribución Aleatoria , Factores de Tiempo , Andamios del Tejido , Cloruro de TolonioRESUMEN
Foi avaliada a relação da espessura do enxerto gengival livre com o potencial desta margem gengival migrar em direção coronal (Creeping Attachment) em pacientes com indicação para este tipo de cirurgia, fazendo uma correlação com as distâncias biológicas. As cirurgias de enxerto gengival autógeno livre foram realizadas em 34 pacientes da Universidade Federal de Goiás (num total de 65 dentes), sendo onze do sexo masculino e vinte e três do feminino. As cirurgias foram realizadas sem o objetivo de recobrimento radicular. Na avaliação inicial foram tomadas as medidas pré-operatórias relativas à profundidade do sulco gengival, recessão gengival e quantidade e espessura da gengiva queratinizada e nível de inserção. As mesmas medidas realizadas na avaliação inicial foram repetidas após trinta dias, 3 e 6 meses e 1 ano pós-operatórios. Os resultados mostraram correlação estatísticamente significante entre a espessura do enxerto e o "Creeping Attachment". Esses resultados sugerem que houve influência decisiva da espessura gengival na determinação das características da gengiva queratinizada resultante, com redução da recessão gengival e posicionamento coronal da margem gengival. No entanto, a ocorrência e a quantidade exata de "Creeping Attachment" não é previsível e não são conhecidos todos os fatores envolvidos.
Asunto(s)
Recesión Gingival , Encía/trasplante , TrasplantesRESUMEN
Estudou-se efetividade antimicrobiana, o pH e o teor de cloro de soluções de hipoclorito de sódio de diferentes concentrações (0,5 por cento, 1 por cento e 2 por cento) e procedências (Dakin Sol - 0,5 por cento, líquido de Dakin - 0,5 por cento, Líquido Dakin - 0,5 por cento, Hi-Clor - 1 por cento Milton Sol - 1 por cento Líquido Milton - 1 por cento Soda Clorada - 2 por cento), encontradas no mercado nacional. A efetividade antimicrobiana foi verificada por teste de exposição direta, a análise de pH com peagâmetro e o teste do teor de cloro pelo método da iodometria. A ação antimicrobiana das soluções testes a 1 e 2 por cento, sobre uma cultura mista (Staphylococcus aureus + Enterococcus faecalis + Pseudomonas aeruginosa + Bacillus subtilis + Candida Albicans), mostrou-se efetiva após 3 minutos; enquanto que, nas concentrações de 0,5 por cento, a efetividade ocorreu decorridos 5 minutos. As soluções comerciais (Dakin, Sol, Maza 2000 - 0,5 por cento; Hi-Clor, Halex Istar - 1 por cento; MIlton Sol, Maza 2000 - 1 por cento e Soda Clorada, Biodinâmica - 2 por cento) apresentaram pH acima de 11. O teor de cloro ativo foi mantido nas seguintes soluções experimentais: líquido Dakin Biodinâmica = 0,5 por cento; Hi-Clor, Halex Istar = 1,07 por cento; Milton Sol, Maza 2000 = 1,06 por cento; Soda Clorada, Biodinâmica = 2,51 por cento