Clinical evaluation of a nanofilled composite in posterior teeth: 12-month results

This study compared the clinical performance of a nanofilled resin composite for posterior restorations with 2 microhybrid and 1 packable composite after 12 months of clinical service. Forty-two patients with at least 5 Class I or II restorations under occlusion were enrolled in this study. A total of 148 restorations were placed, 25% for each material (Filtek Supreme, Pyramid, Esthet-X or Tetric Ceram). Two calibrated operators placed all restorations, according to the manufacturers' instructions. One week later, the restorations were finished/polished. Two independent examiners evaluated the restorations at baseline and after 12 months according to the USPHS modified criteria. All patients attended the 12-month recall and 148 restorations were evaluated. Friedman repeated measures analysis of variance by rank and Wilcoxon sign-ranked test for pair-wise comparison was used for data analysis (alpha=0.05). All materials showed only minor modifications, and no differences were detected between their performance at baseline and after 12 months. After 1 year, the nanofilled resin composite showed similar performance to the other packable and microhybrid resin composites.     

Pattern of tooth loss in recipients of free dental treatment at the University Hospital of Amman, Jordan

The aim of this study is to document reasons for tooth loss in disadvantaged Jordanians who seek free dental care at the University Hospital/Dental Clinics. A 4-year (1998-2001) prospective study was undertaken involving 2200 randomly selected patients from this subpopulation. Of their 3069 lost teeth, 46.9% were lost due to caries and its sequel; 18% were lost because of periodontal disease; 8% were lost for a combination of caries and periodontal disease; 19.4% for pre-prosthetic reasons; 4% for orthodontic reasons; 2.8% for eruption problems and 0.7% due to trauma. Logistic regression analysis for reasons of tooth loss in this sector revealed that caries and its sequel was the predominant cause of tooth loss in patients 相似文献   

Effect of bur type on microtensile bond strengths of self-etching systems to human dentin

PURPOSE: To compare the microtensile bond strength (microTBS) of five adhesives to human dentin prepared with 600-grit SiC abrasive paper (SiC), a diamond rotary instrument, or a carbide bur. The null hypothesis was that different cavity preparation instruments do not affect adhesion of resin adhesives. MATERIALS AND METHODS: Human molars (n = 45) were randomly divided into three groups according to surface treatment. Each group was bonded using a total-etch adhesive (Single Bond, 3M ESPE), one of three self-etching primer systems (Clearfil SE Bond or ABF, Kuraray; Imperva Fluorobond, Shofu), or a self-etching adhesive (One-Up Bond F, Tokuyama). A 4-mm composite crown was built over the bonded surface. Specimens were stored in water for 24 h at 37 degrees C. They were sectioned into 0.7-mm-thick slabs, trimmed to a cross-sectional area of 1 mm2, and loaded to failure at a crosshead speed of 1 mm/min using a tabletop tester (EZ-Test, Shimadzu). Microtensile bond strength data were analyzed using analysis of variance and Fisher's PLSD test. RESULTS: Surface preparation using a carbide bur generally yielded higher bond strengths than preparation using either a diamond rotary instrument or SiC abrasive paper. SE Bond had the highest mean microTBS of the five adhesives tested. CONCLUSION: Resin-dentin bond strengths can be affected by the type of instrument used to prepare the tooth. Specifically, higher bond strengths might be achieved by using carbide burs rather than diamond cutting instruments.     

Relationship of subgingival plaque flora to lysosomal and cytoplasmic enzyme activity in gingival crevicular fluid

Examining the relationships among indicators of the acute inflammatory response in gingival crevicular fluid (GCF) and specific bacterial species in subgingival plaque may provide indications of which bacterial species or groups of species may be associated with potentially destructive host-derived processes. Here we report on the relationship of the subgingival plaque flora to the activity of mammalian forms of the enzymes beta-glucuronidase (beta G), lactate dehydrogenase (LDH), and arylsulfatase (AS) in GCF from a total of 54 4-6 mm periodontal sites from 13 periodontitis patients. Sites were scored for probing depth (PD) and bleeding on probing, and GCF was collected using filter paper strips inserted into the sulcus for 30 s, eluted in buffer and assayed for enzyme activity. 1 week later, the patients were again evaluated for PD and bleeding, and subgingival plaque was removed with a curette oriented toward the pocket epithelium. Plaque samples were examined by darkfield microscopy and cultured anaerobically on selective and non-selective media. Various groups of bacteria, including species of black pigmenting Bacteroides (BPB), Fusobacterium sp., Capnocytophaga sp, Streptococcus sanguis, and total facultative organisms were enumerated. Relationships among the enzymes and bacterial groups expressed as colony-forming unit (CFU) counts or as a % of the total cultivable flora were assessed by Spearman correlation analysis. beta G levels were significantly correlated with populations of spirochetes, B. intermedius, B. gingivalis, and total lactose negative BPB's. Correlation between beta G and F. nucleatum sp. or Capnocytophaga sp. approached but did not reach statistically significant levels. In contrast, LDH activity showed a significant positive correlation with levels of B. gingivalis and total lactose negative BPB's. AS levels were significantly correlated only with B. gingivalis. beta G and LDH showed a significant negative correlation with levels of coccoid forms. Thus, beta G, an acid hydrolase which can serve as a marker for primary granule release from polymorphonuclear leukocytes, was most closely correlated with the micro-organisms found in other studies to be associated with chronic adult periodontitis.     

Marginal fracture of posterior composite resins

This study assesses the early cavomarginal breakdown of the newer posterior composite resin restorations compared with that of amalgam restorations. A total of 432 posterior composite restorations and 73 amalgam restorations were examined: 121 composite restorations (28%) and 44 amalgam restorations (60%) clinically showed a marginal crevice at some point on the cavosurface margin of the restoration at 6-month, 1-year, and 2-year recalls. The largest single reason for poor marginal adaptation was marginal fracture. Up to 2 years, the marginal integrity of the studied posterior composites was superior to that of an amalgam alloy. It was determined that smaller cavities, greater bulk of resin at the margin (especially at functional cusp areas), and well-finished margins without overfiling seem to reduce the occurrence of marginal fracture on composite resin restorations.     

Ultrastructural examination of human periodontal pockets following the use of an oral irrigation device in vivo

To date, there are no ultrastructural studies that have examined untreated chronic periodontal pockets immediately following dental debridement with an oral irrigation device. This study used both scanning electron microscopic and transmission electron microscopic methodology to examine previously untreated human periodontal pockets after their exposure to a pulsating oral irrigation with saline solution. A comparison of 16 untreated controls with 16 test specimens revealed qualitative differences in microbial morphotypes at various pocket depths. Control specimens at all pocket depths examined (0-6 mm), exhibited a mixed microbial flora consisting of cocci, short rods, and filamentous organisms. Specifically at 3- to 4-mm and 5- to 6-mm levels in control specimens, spirochetes, fusiforms, and branching organisms were obvious. In contrast, test specimens exhibited a few cocci and short rods at 0- to 2-mm and 3- to 4-mm levels and a mixed flora at the 5- to 6-mm level. There was no observable difference between control and test specimens concerning epithelial topography, cavitations, microulcerations, spatial relationships, and individual cell appearance. Both control and test specimens exhibited a mild spirochete invasion of the epithelial strata. Collectively these observations suggest that pulsating oral irrigation effects a qualitative change on subgingival plaque and is not injurious to the soft tissues.     

The Brisbane Statistical Division Survey of Adult Dental Health 1984. 3. Dental health status and treatment needs

Dental status and treatment requirements were investigated in 1504 subjects. Mean numbers of decayed, missing and filled (DMF) teeth for the various age groups were: 15–19 years, 6.2; 20–24 years, 10.6; 25–29 years, 15.8; 30–34 years, 18.1; 35–44 years, 20.4; 45–54 years, 23.0; 55–64 years, 26.2; and 65 years and older, 28.7. Total tooth loss did not occur in the 15–19 years or 20–24 years groups. In the 25–29 years group 2.6 per cent of subjects had lost all their teeth, 4.2 per cent in the 30–34 year group and 5.0 per cent in the 35–44 year group. The figures for the older age groups rose dramatically with almost 60 per cent of the 65 year and older age group having lost all their natural teeth. Treatment requirements for all age groups were low. In the 15–19 year age group 62.4 per cent of subjects had no treatment requirements. In other age groups the proportion was lower, ranging from 43.2 to 55.9 per cent. The periodontal condition of subjects was relatively good with only 3.3 per cent requiring complex treatment for severe forms of periodontal disease. A high proportion (over 50 per cent in all but the 15–19 year age group) required scaling and improved personal oral hygiene.     

Immunocytochemical examination of immune cells in periapical granulomata and odontogenic cysts

Monoclonal antibodies (mAbs) were used to determine the presence and distribution of immune cells including lymphocytes, macrophages and Langerhans cells, in normal periodontal ligament, periapical granulomata, periapical cysts and dental developmental cysts. Isolated T-lymphocytes, but not B-lymphocytes, were detected in specimens of non-inflamed periodontal ligament. Increased numbers of T and B lymphocytes were found in all of the lesions examined. Monocytes/macrophages were associated with most periapical granulomata, dental developmental cysts and all periapical cysts. Langerhans cells, intraepithelial lymphocytes, and monocytes/macrophages were not detected in the rests of Malassez but were found in some epithelia within periapical granulomata and in most epithelial linings of odontogenic cysts. Increased numbers of immune cells were seen around proliferative epithelia and adjacent to the epithelial linings of cysts. Epithelium, particularly that of odontogenic cysts, showed positive reactions for HLA-Dr, lysozyme and for α-1 antitrypsin. The presence of immune cells in periapical granulomata and odontogenic cysts, suggests that cell-mediated and humoral immunoreactions occur in these lesions and may be associated with the epithelial proliferation within the periapical lesions.     

Radiographic examination of ectopically erupting maxillary canines

This study analyzes the need for and possibility of obtaining further information from different radiographic procedures in 125 children with potential ectopic eruption of the maxillary canines. After clinical examination of 3,000 10 to 15-year-old children, it was found that 7% needed radiographic examinations for determination of the canine position. Eighty-four children (2.8%), with a total of 125 potential ectopically erupting maxillary canines diagnosed clinically and by means of periapical radiographs, were selected and a stepwise extended radiographic diagnostic procedure was used. Most canines in ectopic eruption were positioned palatally; the positions could be assessed with sufficient accuracy from conventional periapical films in 92% of the cases. Only in 37% of the cases, however, could the lateral incisor be projected free from the ectopic canine by the intraoral technique. The lamina dura of the lateral incisor facing the canine was often found to be interrupted. For 29% of the ectopic canines, the lateral incisors could neither be projected free nor judged free from resorptions and a supplementary polytomographic investigation was believed to be necessary. The number of resorbed teeth was doubled by polytomography and altogether 12.5% of the ectopic canines caused resorptions. A stepwise radiographic procedure including polytomography is described and recommended in cases of ectopic eruption of maxillary canines for determining the correct position and ruling out or confirming resorptions on incisors, thereby optimizing the orthodontic treatment planning.