Introduction. Critical review of the available medical scientific sources demonstrates that despite the wide range of advantages, photopolymer composite materials have certain disadvantages. The main of those are contraction during polymerization and incomplete polymerization of the filling volume.
These disadvantages cause the crevice between the direct restoration and the tooth wall, the possible discoloration can reduce tooth hardness.
Some researchers recommend the application of inlays in order to prevent complications while restoring caries cavities in posterior teeth.
Complete polymerization and reliable adjacency to dental tissues ensure sustainability of indirect photopolymer restoration and prevent secondary caries in restored areas.
Objective. The study is aimed at raising the effectiveness of dental treatment by clinical evaluation of the quality of direct and indirect restorations made from composite materials.
Methods and Materials. In order to conduct comparative clinical evaluation 90 patients with defects of coronal part of lateral teeth, aged 19-54 have been examined, who have orthognathic occlusion, don’t have dental and facial malformations or muscular and joint dysfunctions. They underwent 189 restorations of lateral teeth with cavities of O, MO, OD, MOD types due to medium or severe caries or because of dissatisfying condition of the previously inserted fillings.
The patients were divided into two groups according to the method of treatment. The I (basic) group included 42 patients, who underwent 76 indirect restorations for reconstructing the defects of teeth crowns. The II (test) group included 54 patients, who underwent 113 direct restorations for reconstructing the defects of teeth crowns. Each group was subdivided into two subgroups. The patients who underwent 38 indirect restorations with photopolymer composite material Filtek Z 250 (3M ESPE) were placed in the subgroup I A, the patients who underwent 38 indirect restorations with material Charisma (Heraeus Kulzer) were placed in the subgroup I B. The patients who underwent 57 direct restorations with photopolymer composite material Filtek Z 250 (3M ESPE) were placed in the subgroup II A, the patients who underwent 56 direct restorations with material Charisma (Heraeus Kulzer) were placed in the subgroup II B.
Clinical efficiency of both direct and indirect restorations was evaluated immediately after their application and then after 12 and 24 months with the help of visual and instrumental examination. When secondary caries was suspected, the target X-rays were taken with Heliodent Vario (Sirona). The evaluation was conducted according to the Ryge criteria (1998), approved by USPHS (United States Public Health Service). They include the following indicators: anatomic contour, marginal integrity and marginal coloration, secondary caries, surface texture, preservation of the restoration, restoration fracture, crevice at the edge of restoration, restoration abrasion, tooth fracture, no approximal adjacency, overhanging restoration, localized gingivitis.
Results. The comparative analysis of the clinical efficiency of lateral teeth restorations made from photopolymer materials under study revealed significantly higher quality of indirect restorations (composite inlays), which demonstrated good clinical results even in long-term perspective. Only 5,3% of patients with indirect restorations (with both Filtek Z 250 and Charisma) underwent partial restoration in order to prevent further destruction. By contrast, the patients with direct restorations required the partial restoration in 7% with Filtek Z 250 and 8,9% with Charisma and needed immediate replacement of fillings in 10,5% and 17,8% correspondingly.
A Review on a Straight Bevel Gear Made from Composite
