Biomaterial Database

Studies on posterior composite resins with special reference to class II restorations. 1990

S A Lundin

Department of Pedodontics, Faculty of Odontology, University of Göteborg, Sweden.

Longevity, clinical performance and some related factors of posterior composite resin restorations were investigated through clinical follow-up and laboratory studies in vivo and in vitro. Class I and Class II restorations using two experimental posterior composite resin materials were followed clinically for a four-year period. USPHS evaluation criteria were used. Assessments of wear were also made indirectly using the Leinfelder method. Marginal leakage of bacteria (in vivo) and of dye (in vitro) were studied on modified loaded Class II composite resin restorations lined with GlumaR and LifeR. The grade of conversion (cure) of the posterior composite resin material and the colonization of bacteria at proximal tooth surfaces restored with posterior composite resins were evaluated. Seven per cent of the restorations were evaluated as failures and had to be replaced during a 4-year period. The failures were mainly due to fractures and postoperative sensitivity. The calculated occlusal wear rate was 34-40 microns/year. Occlusal loading of Class II restorations in vitro resulted in a higher frequency of restorations with marginal leakage. The marginal leakage for occlusally-loaded Class II restorations in vivo and in vitro could be reduced if dentine bonding was utilized. The grade of conversion (cure) was increased in the in vivo situation compared to the in vitro. Bacterial colonization of strepococcus mutans on the proximal surfaces of posterior composite restorations showed higher frequencies compared to that on sound tooth surfaces. From the results of these studies, it may be concluded that the tested posterior composite resin materials can be used in Class I and II restorations with a good prognosis for at least 4 years. When posterior composite resins are used as restorative for posterior teeth, the following conditions should be considered: The occlusal loading should be minimal, dentin bonding should be used, the increased risk of colonization of streptococcus mutans should be acted on and regular clinical and radiographical follow-up should be performed.

UI	MeSH Term	Description	Entries
D003188	Composite Resins	Synthetic resins, containing an inert filler, that are widely used in dentistry.	Composite Resin,Resin, Composite,Resins, Composite
D003763	Dental Leakage	The seepage of fluids, debris, and micro-organisms between the walls of a prepared dental cavity and the restoration.	Dental Leakages,Leakage, Dental,Leakages, Dental
D003782	Dental Pulp	A richly vascularized and innervated connective tissue of mesodermal origin, contained in the central cavity of a tooth and delimited by the dentin, and having formative, nutritive, sensory, and protective functions. (Jablonski, Dictionary of Dentistry, 1992)	Dental Pulps,Pulp, Dental,Pulps, Dental
D003793	Dental Restoration, Permanent	A restoration designed to remain in service for not less than 20 to 30 years, usually made of gold casting, cohesive gold, or amalgam. (Jablonski, Dictionary of Dentistry, 1992)	Dental Fillings, Permanent,Dental Filling, Permanent,Dental Permanent Filling,Dental Permanent Fillings,Dental Restorations, Permanent,Filling, Dental Permanent,Filling, Permanent Dental,Fillings, Dental Permanent,Fillings, Permanent Dental,Permanent Dental Filling,Permanent Dental Fillings,Permanent Dental Restoration,Permanent Dental Restorations,Permanent Filling, Dental,Permanent Fillings, Dental,Restoration, Permanent Dental,Restorations, Permanent Dental
D003804	Dentin	The hard portion of the tooth surrounding the pulp, covered by enamel on the crown and cementum on the root, which is harder and denser than bone but softer than enamel, and is thus readily abraded when left unprotected. (From Jablonski, Dictionary of Dentistry, 1992)	Dentine,Dentines,Dentins
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001419	Bacteria	One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.	Eubacteria
D013059	Spectrum Analysis, Raman	Analysis of the intensity of Raman scattering of monochromatic light as a function of frequency of the scattered light.	Raman Spectroscopy,Analysis, Raman Spectrum,Raman Optical Activity Spectroscopy,Raman Scattering,Raman Spectrum Analysis,Scattering, Raman,Spectroscopy, Raman
D013314	Stress, Mechanical	A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.	Mechanical Stress,Mechanical Stresses,Stresses, Mechanical
D013499	Surface Properties	Characteristics or attributes of the outer boundaries of objects, including molecules.	Properties, Surface,Property, Surface,Surface Property