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Optimum gradient material for a functionally graded dental implant using metaheuristic algorithms

Sadollah A, Bahreininejad A

J Mech Behav Biomed Mater, 2011 Oct;4(7):1384-95.
PMID: 21783149 DOI: 10.1016/j.jmbbm.2011.05.009

Despite dental implantation being a great success, one of the key issues facing it is a mismatch of mechanical properties between engineered and native biomaterials, which makes osseointegration and bone remodeling problematical. Functionally graded material (FGM) has been proposed as a potential upgrade to some conventional implant materials such as titanium for selection in prosthetic dentistry. The idea of an FGM dental implant is that the property would vary in a certain pattern to match the biomechanical characteristics required at different regions in the hosting bone. However, matching the properties does not necessarily guarantee the best osseointegration and bone remodeling. Little existing research has been reported on developing an optimal design of an FGM dental implant for promoting long-term success. Based upon remodeling results, metaheuristic algorithms such as the genetic algorithms (GAs) and simulated annealing (SA) have been adopted to develop a multi-objective optimal design for FGM implantation design. The results are compared with those in literature.

Matched MeSH terms: Dental Prosthesis Design/methods*
A denture replication technique following partial maxillectomy: a case report

Haider KG, Lewis GR

Quintessence Int, 1994 Jan;25(1):23-6.
PMID: 8190877

A variety of problems faces the prosthodontist attempting reconstruction of maxillary defects. There are various treatment options for patients requiring a partial maxillectomy and an obturator prosthesis. Reduced adaptability makes it difficult for the patient to learn to use a new appliance, unless existing skills can be employed. It is therefore helpful to reproduce familiar features of a patient's existing obturator, especially if this has been used successfully over a transition period.

Matched MeSH terms: Dental Prosthesis Design/methods*
Effect of CAD-CAM porcelain veneers thickness on their cemented color

Omar H, Atta O, El-Mowafy O, Khan SA

J Dent, 2010;38 Suppl 2:e95-9.
PMID: 20493232 DOI: 10.1016/j.jdent.2010.05.006

To determine the effect of thickness of porcelain veneers constructed from CAD-CAM on their final color when two resin cements were used.

Matched MeSH terms: Dental Prosthesis Design/methods
Finite element analysis of zygomatic implants in intrasinus and extramaxillary approaches for prosthetic rehabilitation in severely atrophic maxillae

Ishak MI, Kadir MR, Sulaiman E, Kasim NH

Int J Oral Maxillofac Implants, 2013 May-Jun;28(3):e151-60.
PMID: 23748334 DOI: 10.11607/jomi.2304

To compare the extramaxillary approach with the widely used intrasinus approach via finite element method.

Matched MeSH terms: Dental Prosthesis Design/methods*
Finite element analysis of different surgical approaches in various occlusal loading locations for zygomatic implant placement for the treatment of atrophic maxillae

Ishak MI, Abdul Kadir MR, Sulaiman E, Abu Kasim NH

Int J Oral Maxillofac Surg, 2012 Sep;41(9):1077-89.
PMID: 22575179 DOI: 10.1016/j.ijom.2012.04.010

The aim of this study was to compare two different types of surgical approaches, intrasinus and extramaxillary, for the placement of zygomatic implants to treat atrophic maxillae. A computational finite element simulation was used to analyze the strength of implant anchorage for both approaches in various occlusal loading locations. Three-dimensional models of the craniofacial structures surrounding a region of interest, soft tissue and framework were developed using computed tomography image datasets. The implants were modelled using computer-aided design software. The bone was assumed to be linear isotropic with a stiffness of 13.4 GPa, and the implants were assumed to be made of titanium with a stiffness of 110 GPa. Masseter forces of 300 N were applied at the zygomatic arch, and occlusal loads of 150 N were applied vertically onto the framework surface at different locations. The intrasinus approach demonstrated more satisfactory results and could be a viable treatment option. The extramaxillary approach could also be recommended as a reasonable treatment option, provided some improvements are made to address the cantilever effects seen with that approach.

Matched MeSH terms: Dental Prosthesis Design/methods*
An In Vitro Study of Retention and Marginal Adaptation of Endocrowns With Different Intracoronal Depths

Tiew EC, Azis N, Teh LA, Shukor S, Goo CL

Oper Dent, 2024 Jul 01;49(4):403-411.
PMID: 38978316 DOI: 10.2341/23-063-L

BACKGROUND: Marginal adaptation and retention of endocrowns are crucial for the success and survival of endocrowns. This study aimed to investigate the effect of different materials and intracoronal depth on the retention and marginal adaptation of CAD/CAM fabricated all-ceramic endocrowns.
METHODS: Thirty-six mandibular premolar teeth with an average surface area of 64.49 mm2 were prepared to receive CAM/CAM fabricated endocrowns. Samples were divided randomly and equally into groups of lithium disilicate with 2 mm intracoronal depth (LD2), lithium disilicate with 4 mm intracoronal depth (LD4), polymer infiltrated ceramic network with 2 mm intracoronal depth (PICN2) and polymer infiltrated ceramic network with 4 mm intracoronal depth (PICN4). All endocrowns were cemented using ParaCore resin cement with 14N pressure and cured for 20 seconds. Fifty measurements of absolute marginal discrepancy (AMD) were done using a stereomicroscope after cementation. After 24 hours, all samples were subjected to thermocycling before the retention test. This involved using a universal testing machine with a crosshead speed of 0.5 mm/min and applying a load of 500N. The maximum force to detach the crown was recorded in newtons and the mode of failure was identified.
RESULTS: Two-way ANOVA revealed that the AMD for PICN was statistically significantly better than lithium disilicate (p=0.01). No statistically significant difference was detected in the AMD between the two intracoronal depths (p=0.72). PICN and endocrowns with 4 mm intracoronal depth had statistically significant better retention (p<0.05). 72.22% of the sample suffered from cohesive failures and 10 LD endocrowns suffered adhesive failures.
CONCLUSIONS: Within the limitations of this study, we found that different materials and intracoronal depths can indeed influence the retention of CAD/CAM fabricated endocrowns. Based on the controlled setting findings, PICN was found to have better retention and better marginal adaptation than similar lithium disilicate premolar endocrowns.

Matched MeSH terms: Dental Prosthesis Design/methods