Influence of diameter in the stress distribution of extra-short dental implants under axial and oblique load: a finite element analysis

Aim: This study evaluated the influence of a wide diameter on extra-short dental implant stress distribution as a retainer for single implant-supported crowns in the atrophic mandible posterior region under axial and oblique load. Methods: Four 3D digital casts of an atrophic mandible, with a single implant-retained crown with a 3:1 crown-to-implant ratio, were created for finite element analysis. The implant diameter used was either 4 mm (regular) or 6 mm (wide), both with 5 mm length. A 200 N axial or 30º oblique load was applied to the mandibular right first molar occlusal surface. The equivalent von Mises stress was recorded for the abutment and implant, minimum principal stress, and maximum shear stress for cortical and cancellous bone. Results: Oblique load increased the stress in all components when compared to axial load. Wide diameter implants showed a decrease of von Mises stress around 40% in both load directions at the implant, and an increase of at least 3.6% at the abutment. Wide diameter implants exhibited better results for cancellous bone in both angulations. However, in the cortical bone, the minimum principal stress was at least 66% greater for wide than regular diameter implants, and the maximum shear stress was more than 100% greater. Conclusion: Extra-short dental implants with wide diameter result in better biomechanical behavior for the implant, but the implications of a potential risk of overloading the cortical bone and bone loss over time, mainly under oblique load, should be investigated

Zygomatic implants in intra-sinus versus extra-maxillary approaches for prosthetic rehabilitation in severely atrophic maxillae: finite element analysis / Implantes cigomáticos en abordajes intra sinusal versus extra maxilar para rehabilitación protésica en maxilares severamente atróficos: análisis de elementos finitos

Objetive: To compare the stresses and deformations generated on the surrounding bone of the zygomatic implants when using an intra sinusal and extra-maxillary approach, through the finite element method. Material and Methods: Computer aided designs (CADs) were constructed using SolidWorks Software of a skull with bone resorption to be rehabilitated through a fixed hybrid prosthesis using two zygomatic and two conventional straight implants. For the boundary conditions (load conditions), symmetry in the sagittal plane was assumed and that all the materials were isotropic, homogeneous and linearly elastic. Two zygomatic implantation techniques were simulated: intra sinusal (Is) and extra maxillary (Em). Vertical and lateral loads of 150 N and 50 N were applied to the finite element models to obtain Von Mises equivalent stress and strain (displacement). Results: The average measurement of the Von Mises stress (MPa) recorded were as follows: Approach of the implant body (Is: 0.24- Em: 0.28,) effort of implant body with vertical load: Is: 0.69 - Em: 0.96; effort of peri-implant surface under horizontal load: Is: 2.11 - Em: 0.94. Average displacement under vertical load of peri-implant surface Is: 0.35 - Em: 0.40, and of implant body Is: 1.34 - Em: 2.04. Average total deformation in approach Is: 2.23 mm - Em: 0.80mm, and average total deformation in the implant body under horizontal load was Is: 0.14 - Em: 0.21. Conclusion: The results of this study indicate that despite the differences that occurred in both stress and strain (displacement) between the intra-sinus and extra-maxillary approaches, the static strength of the bone, which is approximately 150 MPa in tension and 250 MPa in compression was not exceeded. Considering the limitations of finite element analysis, there seems to be no biomechanical reason to choose one approach over the other.

Objetivo: Comparar por el método de elementos finitos los esfuerzos y deformaciones generados sobre el hueso circundante de implantes cigomáticos tratados con un abordaje intra sinusal y extra maxilar. Material y Métodos: Se construyeron los diseños asistidos por computadora (CAD) utilizando el Software SolidWorks de un cráneo con una reabsorción ósea para ser rehabilitado, a través de una prótesis híbrida fija, mediante dos implantes cigomáticos y dos rectos convencionales. Para las condiciones de frontera (condiciones de carga) se asumió simetría en el plano sagital y que todos los materiales eran isotrópicos, homogéneos y linealmente elásticos. Se simularon dos técnicas de implantación cigomática: una intra sinusal (Is) y otra extra maxilar (Em). Se aplicaron cargas verticales y laterales de 150 N y 50 N a los modelos de elementos finitos para obtener el esfuerzo equivalente de Von mises y la deformación (desplazamiento). Resultados: La medición promedio del esfuerzo de Von Mises (MPa) registró: abordaje del cuerpo de implante (Is: 0.24-Em: 0.28) esfuerzo del cuerpo de implante con carga vertical: (Is:0.69 ­ Em: 0.96); esfuerzo de la superficie peri implantar ante carga horizontal (lateral):( Is:2.11 ­ Em:0.94). Desplazamiento promedio ante carga vertical de la superficie peri implantar (Is:0.35 ­ Em:0.40) y del cuerpo del implante (Is:1.34 ­ Em:2.04). Deformación total promedio en mm en abordaje (Is: 2.23 ­ Em:0.80) y deformación total promedio en el cuerpo del implante ante carga horizontal (Is:0.14 ­ Em:0.21). Conclusión: Los resultados de este estudio indican que a pesar de las diferencias que se presentaron tanto en el esfuerzo como en la deformación (desplazamiento) entre los abordajes intra sinusal y extra maxilar, la resistencia estática del hueso, que es de aproximadamente 150 MPa en tensión y 250 MPa en compresión no se superó. Considerando las limitaciones de los AEF, parece no haber razones biomecánicas para elegir uno u otro enfoque.

Rehabilitation of atrophic posterior partial edentulous maxilla with TTPHIL ALL TILT® technique: 3 year follow-up case report / Reabilitação de maxila atrófica posterior parcialmente desdentada com técnica TTPHIL ALL TILT®: relato de caso de acompanhamento de 3 anos

Maxillary sinus pneumatisation pose a grave clinical challenge for implant fixed rehabilitation in posterior maxilla owing to diminished bone volume. This necessitates sinus lift and grafting which increase the duration and cost and possible surgical complications. Pterygoid implant has a greater short term osseointegration and is a proven treatment method for rehabilitation of highly resorbed posterior maxilla. To overcome the limitations of sinus grafting techniques, the current case report describes the use of flapless, tilted and pterygoid implant for restoration of partially edentulous atrophic maxilla eliminating grafting (AU).

A pneumatização do seio maxilar representa um grande desafio clínico para a reabilitação fixa por implante na região posterior da maxila devido ao volume ósseo diminuído. Isso requer elevação do seio e enxerto, fatores que aumentam a duração, o custo e as possíveis complicações cirúrgicas. O implante pterigóide tem uma osseointegração maior em curto prazo e é um método de tratamento comprovado para reabilitação de maxila posterior altamente reabsorvida. Para superar as limitações das técnicas de enxerto de seio, o relato de caso atual descreve o uso de implante sem retalho, inclinado e pterigóide para restauração de maxila atrófica parcialmente edêntula eliminando o enxerto.(AU)

Comportamiento de las enfermedades bucodentales en el Hospital Referal Maliana de Timor Leste / Behavior of oral and dental diseases at Referal Maliana Hospital, Timor Leste

RESUMEN Introducción: la salud bucodental es un indicador clave de salud, bienestar y calidad de vida. Las enfermedades bucodentales como caries, periodontopatías, cáncer bucal pueden prevenirse y tratarse en sus etapas iniciales. Objetivo: determinar el comportamiento de las enfermedades bucodentales en la población que asistió a la consulta de estomatología del Hospital Referal Maliana, distrito Bobonaro, Timor Leste durante 2017-2018. Métodos: estudio observacional descriptivo de corte transversal en 480 pacientes afectados con alguna patología bucodentaria, seleccionados por muestreo intencional no probabilístico. Resultados: predominó el sexo masculino (51,9 %), el grupo de edad más afectado fue 10-19 años (40,4 %), las patologías más diagnosticadas fueron las caries (79,1 %) en edades entre 0 y 39 años, gingivitis (58,6 %) en jóvenes, y desdentamiento parcial (49,4 %) en todas las edades. Prevaleció la higiene bucal deficiente (83,8 %) en ambos sexos y consumo de mama malus (64,8 %) más observado en mujeres. Conclusiones: la población timorense estudiada es mayormente masculina, predominó el grupo de edad de 10 a 19 años; las enfermedades bucodentales más frecuentes fueron las caries en menores de 40 años, gingivitis en jóvenes, y edentulismo parcial en todas las edades. Los principales factores de riesgo asociados fueron la higiene bucal deficiente para ambos sexos y masticación de la mama malus (nuez de Areca o de betel) en las féminas, lo que evidencia una alta probabilidad de que incremente y confirma la severidad de las enfermedades bucodentales como problema de salud en esta población.

ABSTRACT Introduction: oral-dental health is a key indicator of wellbeing and quality of life. Oral-dental diseases as caries, periodontopathies and oral cancer can be prevented and treated at early stages. Objective: to determine the behavior of oral-dental diseases in the population attending the dentistry office at Referal Maliana Hospital, Bobonaro district, Timor Leste during 2017-2018. Methods: observational, descriptive and cross-sectional study in 480 patients who suffered from some of the oral-dental pathologies chosen by non-probabilistic intentional sampling. Results: male sex prevailed (51,9 %), the age bracket most affected was 10-19 years old (40,4 %), dental caries was the pathology having the highest diagnosis (79,1 %) between 0 and 39 years old, gingivitis (58,6 %) in young patients and partially-toothless patients in all ages. Deficient oral hygiene prevailed in both sexes (83,8 %) and mama malus consumption (64,8 %) more observed in women. Conclusions: the East Timorese population studied was mainly male, the predominant age group was 10-19 years; the most frequent oral-dental diseases were caries in younger than 40 years old, gingivitis in young population and partial edentulous in all ages. The main risk factors associated were deficient oral-dental hygiene for both sexes and the mastication of mama malus (Areca Nut or Betel Quid) in female population, which evidences a high probability of a continuous increasing and confirms the severity of the oral-dental diseases as a health problem in this population.

An assessment of accuracy of half-guided implant surgery using implant surgical guide: A case report / 대한치과보철학회지

Nowadays, dental implant is one of the widely used treatment options for edentulous patients. Recently, a method of improving the accuracy of implant surgery using an implant surgical guide has been introduced and widely used in order to accurately place the implant in a proper position. Full-guided and half-guided implant surgery can be distinguished according to the level of surgical guide application during the implant surgery. It is true that full-guided implant surgery exhibits higher accuracy, but half-guided implant surgery is often performed in a clinical situation due to the factors such as the circumstances of the operation. A partially edentulous patient who lost teeth due to tooth fracture and periodontal disease was treated using implant and fixed prosthesis. Half-guided implant surgery was performed using an implant surgical guide during implant surgery, the accuracy of implant placement was analyzed.

Can implant surfaces affect implant stability during osseointegration? A randomized clinical trial

Abstract This randomized clinical trial evaluated the insertion torque (IT), primary, and secondary stability of dental implants with different surface treatments during the osseointegration period. Nineteen patients with bilateral partial edentulism in the posterior mandibular region were randomly allocated to two implant brand groups and received implants with different surface treatments in the opposite site of the arch: Osseotite and Nanotite or SLA and SLActive. During implant placement, the maximum IT was recorded using a surgical motor equipped with a graphical user interface. The implant stability quotient (ISQ) was assessed immediately after the IT, and was measured weekly via resonance frequency analysis during 3 months. The data were analyzed by a one-way ANOVA, the Bonferroni test, paired t tests and Pearson's correlation coefficient. The IT values were similar (p > 0.05) for all implant types ranging from 43.82 ± 6.50 to 46.84 ± 5.06. All implant types behaved similarly until the 28th day (p > 0.05). Between 35 and 56 days, Osseotite and SLActive showed lower ISQ values (p < 0.001) compared to Nanotite and SLA implants. After 56 days, only Osseotite maintained significantly lower ISQ values than the other implants (p < 0.05). After 91 days the ISQ values were significantly higher than the baseline for all four implant types (p < 0.001). The ISQ and IT values were significantly correlated at the baseline and at the final evaluation for Osseotite, Nanotite, and SLActive implants (p < 0.001). After 91 days, ISQ and IT values were only significantly correlated for the Osseotite implants (p < 0.05). All implants types exhibited acceptable primary and secondary stability.