Posterior teeth

Knight, G. M. (1984). The use of adhesive materials in the conservative restoration of selected posterior teeth. Australian Dental Journal, 29, 324-31. 

R. Hickel, J. Manhart, Longevity of restorations in posterior teeth and reasons for failure, J. Adhes. Dent. 3 (2001) 45-64. 

The primary failure modality identified clinically for restorations in posterior teeth is loss of material through abrasion. The complex nature of this failure mode in composite materials makes it difficult to correlate this phenomenon with any one mechanical property. A number of studies have suggested improvements in the system by using various mechanical properties as evidence. These studies have identified major factors such as ceramic filler loading and type of filler [186-191]. Some effects have been identified related to the... 

Tooth type and position are often noted with a combination of numbers and letters, depending on the species. Each tooth has a lingual side, adjacent to the tongue, and a labial surface, which is closest to the lips (if there are any). The posterior teeth are at the back of the mouth, and the anterior to the front. The occlusal surface is the area where opposing teeth meet during chewing or biting. 

Preliminary nanoindentation results on other teeth (premolars, incisors and canines) indicate variations in mechanical properties as large as those discussed for molars [unpubl. data]. In each case the exact distribution of mechanical properties within the enamel appears to correlate with the extent of mechanical loading experienced by the tooth during mastication. However, there appears to be an increase in the viscoelasticity (loss modulus) for the enamel of anterior teeth when compared to posterior teeth, again this may be related to their function. 

Khera SC, Carpenter CW, Vetter JD, Staley RN Anatomy of cusps of posterior teeth and their fracture potential. J Prosthet Dent 1990 64 139-147. 

Fig. 15.1 Severe, untreated dental caries. Dental caries initially affects the occlusal pits and fissures of posterior teeth. In severe caries, the smooth surfaces, especially the interdental surfaces of all teeth may be involved...

Recently, polyphase acrylic polymers have become increasingly important. They are the preferred materials for restoring anterior teeth where esthetic considerations are paramount. However, they are not satisfactory for the restoration of posterior teeth, especially in load-bearing locations where mechanical properties, such as abrasion resistance, are important (7). These materials are also used to make hip prostheses, and they are finding increasing application in orthopedics (8). 

Numerous thermal analysis studies have been performed by other groups on resin composites, which are used for small anterior restorations that do not experience substantial stress and with caution for posterior teeth because of concern about wear [1-3]. The polymer matrix contains the oligomer bis-GMA (bisphenol A-glycidyl methacrylate) or urethane dimethacrylate, and triethylene glycol dimethacrylate is a diluent. Filler particles are silane-coated for chemical bonding with tire matrix. Free-radical polymerization is carried out by chemical... 

PC teeth were irradiated by an EB accelerator of 2 MeV at 150°C, where the teeth specimens were arranged in the irradiation vessel in the same position as in Figure 12.8. EB penetrates into the anterior teeth, but the penetration to the posterior teeth was about 4 mm from the surface. The radiation-induced improvement of the hardness and wear resistance was the same as with the PC sheet. The coloring of teeth by irradiation up to 10 kGy was not observed. 

Teeth with decayed regions have traditionally been restored with metals such as silver amalgam. Metallic restorations are not considered desirable for anterior teeth for cosmetic reasons. Acrylic resins and sihcate cements had been used for anterior teeth, but their poor material properties led to short service life and clinical failures. Dental composite resins have virtually replaced these materials and are very commonly used to restore posterior teeth as well as anterior teeth [Cannon, 1988]. 

Dental composite resins have become established as restorative materials for both anterior and posterior teeth. The use of these materials is likely to increase as improved compositions are developed and in response to concern over long term toxicity of silver-mercury amalgam fillings. 

S.H. Mahmoud, A.E. El-Embaby, A.M. Abdallah, H.H. Hamama, Two-year clinical evaluation of oimocer, nanohybrid and nanofill composite restorative systems in posterior teeth, J. Adhes. Dent. 10 (2008) 315-322. 

W. Dresch, S. Volpato, J.C. Gomes, N.R. Ribeiro, A. Reis, A.D. Loguercio, Clinical evaluation of a nanofilled composite in posterior teeth 12-month results, Oper. Dent. 31 (2006)409 127. 

Z. Ergiicu, L.S. Ttirkiin, Clinical performance of novel resin composites in posterior teeth 18-month results, J. Adhes. Dent 9 (2007) 209-216. 

The oxirane rings are responsible for the physical properties and the low shrinkage, while the hydrophobic properties of the material are related to the siloxanes [61]. As a consequence, exogenous discolouration and water absorption are reduced. All these reported advantageous characteristics serve to enhance the potential of silorane monomers to be used successfully in dental composite materials. Weinmann et al. [54] observed a low shrinkage rate (<1 %) and seven times more light stability for the silorane in comparison with resin-based methacrylates. The clinical application of siloranes is limited to the posterior teeth because only a few low translucent colours are available. Additionally, due to its hydrophobic properties, a special adhesive system must be used for silorane restorations. 

Pit and fissure sealants (12) used as caries preventive treatment for filling deep fissures in posterior teeth, primarily deciduous molars, are rather popular despite the controversy on the economic efficacy. The sealants now in use are composed of methyl methacrylate, Bis-GMA and/or urethane methacrylate mixtures. They are applied to phosphoric acid-etched occlusal surface in a very fluid state to flow into the surface (Fig. 11), and cured by U.V. or are self curable. They attach to the enamel by mechanical locking into the etched surface rather than by adhesion. 

Providing sensation of individual teeth, e.g. anterior teeth not affecting posterior teeth... 

The wear of dental composite restorative materials observed clinically in anterior and posterior teeth may be caused by abrasion, sliding, chemical erosion, or some combination of these mechanisms. This paper reviews experimental methodology for the study of wear of dental composite materials in vitro and in vivo. 

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