Vertical mammaplasty as secondary surgery after other techniques

The effect of ultrasonic insertion on the filler content and the gap width for two brands of composite resin luting agents, intended for luting with the ultrasonic insertion technique, were studied after MOD ceramic inlays (Cerec) had been placed. In addition, the internal and marginal gap widths were determined after MOD ceramic inlays (Celay) bad been luted on extracted premolars with this technique. No statistically significant differences (P > 0.05) were observed for either brand between the filler content obtained from the internal surfaces, from the excess luting agent, or from the luting agent as delivered. There were no statistically significant differences (P > 0.05) between the final internal and marginal gap widths when the two brands of luting agent were compared with each other. Except for the final occlusal and internal gap widths obtained for the inlays luted with the Sono-Cem luting agent, no statistically significant differences (P > 0.05) were observed between the gap widths at the different locations determined. Thus, the ultrasonic insertion technique used did not significantly influence the filler ratio of the hybrid luting agents studied. Judged by the findings in this study, the properties of luting agents seem to greatly influence the final marginal and internal gap widths.     

In vivo and in vitro evaluation of marginal integrity in ceramic inlays

The marginal integrity is an important factor for the long-term success of ceramic inlays. The long term clinical performance of porcelain inlays depends on a number of factors of which the marginal adaptation is of significant interest. The aim of this study was to determine the margin quality of adhesively luted sintered porcelain inlays both in vivo and in vitro. MOD cavities without bevels were prepared on 10 extracted human mandibular molar teeth. Using the Ducera inlay system, inlays were fired on refractory dies and luted with a dual-curing composite resin. After polishing, each, tooth was sectioned in buccal/lingual and mesial/distal directions and marginal adaptation was assessed microscopically. The mean marginal gap of 78.77 +/- 14.85 microns recorded for occlusal margins was significantly smaller than that of 128.85 +/- 34.34 microns seen at the approximal margins. For in vivo evaluation, 25 fired porcelain inlays, including 7 onlays, were placed in Class II cavities. The assessment of the marginal adaptation of inlays was made according to the scaling system used by Aberg et al. (Acta Odontol Scand 1994; 52:140-149). In 19 of the clinical cases, the restoration was contiguous with the existing anatomic form. Both in vivo and in vitro evaluations showed the margin quality of porcelain inlays to be high.     

Comparison of marginal fit and microleakage of ceramic and composite inlays: an in vitro study

The purpose of this in vitro study was to evaluate the marginal fit and microleakage of four types of ceramic or resin composite inlays. Sixty extracted human third molar teeth were randomly assigned into four groups. MOD cavities without bevels were prepared. The mesiogingival margin was cut in enamel, whereas the distogingival margin was placed below the amelocemental junction. The preparations and inlays were made according to the manufacturers' instructions. After acid-etching and treatment with a dentine bonding agent the inlays were cemented with dual curing CEREC resin composite luting material. After placement and polishing 10 teeth of each group were thermocycled 2500 times between 14 degrees C and 62 degrees C. Each tooth was bisectioned and from each part, one occlusal and three proximal sections of 75-100 microns thickness were cut and ground (EXAKT Cutting and Grinding system). The marginal discrepancy and the thickness of the luting cement were measured microscopically at each section and an average for each tooth was calculated. Considerable variation of marginal fit was seen, within inlays, and among different types of inlays. In general, the Vita Dur N inlays showed the best fit, e.g. the thickness of the luting cement for Vita Dur N was 114 microns occlusally and 119 microns mesiogingivally compared to 199 microns occlusally for CEREC and 219 microns mesiogingivally for Estilux. At enamel margins, a tendency of less microleakage was seen for ceramic inlays compared to composite inlays.     

Resin-modified glass ionomers for luting posterior ceramic restorations

OBJECTIVES: Until recently, esthetic inlay restorations in posterior teeth have been limited to cavities surrounded by enamel. Dentin adhesive systems in combination with luting composites and light-cured resin-modified glass ionomer cements offer a possibility for bonding ceramic inlays to cavities when the cervical margin is in dentin. This study was designed to compare in vitro marginal integrity of ceramic inlays bonded to dentin to restorations placed in cavities with margins located entirely in the enamel. METHODS: In the present in vitro study, the sealing abilities of a dentin bonding agent/luting composite combination (Syntac/Dual Cement, Vivadent) and resin-modified glass ionomers (Photac Fil, Photac Bond, ESPE; Dyract, De Trey Dentsply; Fuji II LC, GC Dental Industrial Corp.; and Vitremer, 3M Dental Products) used as luting agents in cavities extending beyond the cemento-enamel junction, were compared to the sealing abilities of a conventional luting composite (Vita Cerec Duo Cement, Vita) in cavities within sound enamel. SEM analysis and dye penetration were performed to evaluate marginal integrity at the cervical cavity margins. RESULTS: The dentin bonding agent/luting composite combination (Syntac/Dual Cement) rendered a marginal seal within the dentin similar to the quality obtained with the conventional luting procedures within sound enamel. When three out of the five resin-modified glass ionomers were used as luting agents (Dyract, Fuji II LC and Vitremer), the results were comparable to those reported for the dentin bonding agents and the conventional method. SIGNIFICANCE: Light-cured resin-modified glass ionomer cements may be considered as an alternative to dentin bonding agents when the cavity margins of ceramic inlay restorations are within the dentin. However, further studies, e.g., wear resistance, must be performed.     

Wear resistance of four luting agents as a function of marginal gap distance, cement type, and restorative material

This study investigated the effect of marginal gap width, luting cement, and restorative material on the wear resistance of the luting cement in areas where no occlusal contact is present. Three types of resin luting cement and one resin-modified glass-ionomer cement were used with two inlay systems, a resin composite, and an all-ceramic system. Bovine enamel represented tooth structure. Toothbrush abrasion was the wear modality. Three predetermined gap widths were selected: 240 +/- 30 microns, 150 +/- 30 microns, and 60 +/- 30 microns. All specimens were thermocycled. Regardless of the luting cement or the restorative material, there was a significant difference (P < 0.05) in wear resistance of the cement among the three gap distances at both the enamel and restoration interface. Vertical wear of the luting cement at the enamel interface increased linearly with marginal gap distance when all four cements were considered together (r2 > 0.51), regardless of type of restorative material used. The resin-modified glass-ionomer cement showed the least amount of wear for all variables considered. Significant differences in wear were found between the four luting cements at wide gap distances (240 microns) at the enamel interface, regardless of type of restorative material used. No significant differences were found between the two restorative materials at the enamel interface at the three gap distances.     

Evaluating interfacial gaps for esthetic inlays

Because of some inadequacies associated with the direct fill posterior composite resin, the inlay/onlay form of the same material or ceramic agents has been introduced. This clinical investigation measured the wear rate of several types of luting agents with both resin and ceramic restorative systems and identified several factors related to wear of the cementing agent.     

Race, life style and renal disease in South Africa

PURPOSE: Clinical evaluation of repairing old amalgam restorations using composite inlays cemented with two different bonding agents. MATERIALS AND METHODS: Occluso-proximal Class II inlay cavities were prepared in 50 old defective amalgam restorations. Extra oral system (EOS) composite inlays were cemented with two different bonding agents (All-Bond 2 or Geristore). After final finishing and polishing of each restoration, evaluation was carried out at baseline, 6 months, 12 months, and 24 months using US Public Health Service criteria. The data were collected and statistically analyzed using Chi-square test. RESULTS: No significant difference was found between the two bonding materials at any time interval.     

Resin modified glass ionomer cements. In vitro microleakage in direct class V and class II sandwich restorations

Microleakage of conventional chemically cured and resin modified glass ionomer cements (GIC), a compomer and a composite resin was studied in vitro in direct class V and class II GIC/composite sandwich fillings. None of the restorative techniques investigated completely resisted microleakage at both the occlusal and gingival margins. The dentinal gingival margins exhibited the highest leakage pattern. The compomer and the resin modified GIC showed a better seal than the chemically cured GIC's. The use of a liner as separating agent between composite resin and GIC in the class II sandwich fillings did not improve the seal. The results suggest that the initial bond obtained immediately after light curing of the resin modified GIC's is stronger than that for chemically cured GIC's. The contradictory results of dye leakage studies reported in the literature are discussed and in vivo evaluations are suggested necessary to predict clinical performance.     

In vitro evaluation of marginal and internal adaptation of class II resin composite restorations after thermal and occlusal stressing

The aim of this in vitro trial was to evaluate the external and internal adaptation of class II composite restorations to tooth structure by means of replica scanning electron microscope (SEM) observation. Standard MOD preparations were cut in human extracted teeth with margins located above and below the cementoenamel junction. Cavities were restored with either a direct multilayered technique, inlays (using conventional or dual DBA application) or prepolymerized composite inserts, using similar restorative material (Syntac, Variolink and Tetric). Evaluations were performed after mechanical and thermocycling. For the marginal adaptation in enamel, the bevelled margins of the direct group resulted in higher percentages of "continuity" (92.5% mesially and 94.6% distally), while the "marginal tooth fracture" was the most commonly found defect in groups with a butt preparation (up to 29.4%, with inserts). For the marginal adaptation in dentin, "continuity" percentages varied from 59% (inlay) to 87.9% (insert). As regards the internal adaptation, results for the whole dentin interface varied from 43.1% (inlay) to 63.9% (inlay with dual bonding) of "continuity". No regional difference in internal adaptation was found between the different preparation areas, except between gingival dentin and gingival enamel (44.9% vs. 80.7% of continuity, all group pooled data). Debonding occurred only at the dentin-restoration interface and consistently took place at the top of the hybrid layer. In the present experimental conditions, the inlay or insert techniques, which make use of the Dual bonding concept, proved to have the best potential to maintain the integrity of dentin-restoration interface.     

Effect of polymerization mode of a dual-cured resin cement on time-dependent shear bond strength to porcelain

PURPOSE: To evaluate the shear bond strengths to porcelain and setting times of a dual-cured resin cement with light/chemical curing (dual) or chemical only curing versus time. MATERIALS AND METHODS: Variolink resin cement was bonded to specimens of etched, silanated porcelain. Groups of specimens were cured by dual cured or by chemical curing only. Shear bond strengths were recorded at 2, 3, 5, 60 minutes and 24 hours for dual cured and at 10, 20, 40, 50, 60 minutes and 24 hours for chemical-cured only after mixing. Kinetic-temperature profiles of dual and chemical curing modes of cement were calculated. RESULTS: Maximum bond strengths and time to attainment were 17.5 +/- 2.7 MPa at 60 minutes for chemical-cured and 26.1 +/- 2.3 MPa at 5 minutes for dual-cured. The peak in the kinetic-temperature setting profiles were 14.1 +/- 0.9 minutes for chemical curing and 52.2 +/- 5.2 seconds for dual curing. Dual curing provided significantly higher shear bond strengths versus chemical curing at both the 60-minute and 24-hour time periods.     

Benefits and disadvantages of tooth-coloured alternatives to amalgam

OBJECTIVES: To give the practising dentist scientifically based data to assist him/her in the responsible decision-making process necessary to weigh the options available to the patient if she/he prefers not to have an amalgam placed. DATA SOURCES: Based on the literature and on the research work, which was done in the author's department, the indications and limitations of the known alternatives of amalgam were formulated. DESCRIPTION OF ALTERNATIVES TO AMALGAM: With the exception of cast gold restorations, all alternatives require the strict use of adhesive techniques. When compared with similar amalgam restorations, placing composite restorations (if they are indicated) takes approximately 2.5 times longer because complex incremental techniques are needed. Despite all the efforts, direct composite restorations placed in large cavities still show unacceptable amounts of marginal openings. Tooth-coloured inlays are a better alternative for large restorations. These restorations must be inserted with adhesive techniques. With composite inlays it is difficult to achieve a composite-composite bond. Ceramic inlays may be micromechanically bonded to the luting composite. They all show clinically a good marginal behaviour and the use of ultrasonic energy may further simplify the application technique of aesthetic inlays. STUDY SELECTION: Papers describing the different techniques were used as a base for the corresponding chapter. To assess and compare the longevity of the different restoration types, literature data were used. We limited ourselves to papers reporting at least 5-year clinical data. Longitudinal, clinically controlled studies were preferred. However, to be more complete, retrospective, cross sectional studies were also included. LONGEVITY OF POSTERIOR RESTORATIONS: Amalgam shows excellent longevity data with studies up to 20 years. The average annual failure rate is 0.3-6.9%. Posterior composites are in the same range (0.5-6.6%), however, the study times are much shorter (max. 10 years). For tooth-coloured inlays much less data are available. Longevity is reported up to 6 years with annual failure rates of 0.6-5%. CONCLUSIONS: All aesthetic alternatives to amalgam require more complex procedures and more time. If cost benefit considerations are a concern, amalgam is still the most convenient restorative material for posterior teeth.     

The relationship between abutment taper and resistance of cemented crowns to dynamic loading

This study investigated the relationship between abutment total occlusal convergence angle (taper) and the resistance of cemented crowns subjected to dynamic loading. Crown and abutment analogs were placed using zinc-oxide-eugenol, zinc-phosphate, glass-ionomer, or resin composite cement. Total occlusal convergence angles of 2.5, 5, 10, 15, 20, 30, and 40 degrees were used. Dynamic stresses were applied to the luted components until the bond failed or the components reached 10(6) load cycles. The data were analyzed using the staircase technique. The relationship between convergence and resistance was approximately linear for all the cements tested. Crowns luted with resin composite cement were more resistant to dynamic lateral loading than those placed using glass-ionomer or zinc-phosphate cements. Crowns luted with zinc-oxide-eugenol cement presented the least resistance to cyclic lateral stresses.     

Amalgam alternatives--micro-leakage evaluation of clinical procedures. Part I: direct composite/composite inlay/ceramic inlay

This study investigated the degree of dye penetration with three different types of tooth-coloured restorations. Twenty-four intact extracted molars were collected. The teeth were immediately stored in water at room temperature. Class II cavity preparations were prepared and restored with three different types of tooth-coloured restorations: A, composite resin in the incremental technique; B, composite inlay technique; and C, ceramic inlay. Specimens were subjected to 700 cycles of thermal stress. They were than immersed in 2% basic fuchsin dye. The teeth were sectioned in three planes before being ranked as to the amount of dye penetration. The highest score obtained on three plano-parallel sections was adopted as the representative value. The three groups were compared using the Kruskal Wallis non-parametric test. Dye penetration was significantly lower at the enamel margins when using the composite inlay system and the incremental technique compared to the ceramic inlay technique. The restorations placed using the composite inlay technique showed less dye penetration than the incremental technique at the dentine margins (P < 0.017).     

Stability of radicals in cured composite materials

During the radical polymerization of dental composites, the monomers polymerize to form a three-dimensional network containing remaining double bonds and free radicals. At 37 degrees C, these radicals decompose logarithmically with a half-life of 2-5 d. In this study, the half-life of radicals in a light-cured inlay composite was determined at different temperatures, and the influence of different fillers and filler amounts on the stability of these radicals in light-cured experimental composites was investigated. There is a strong logarithmic relationship between the half-life of the radicals and temperature. At a constant temperature, the half-life of radicals depends on the type of filler, the filler fraction, and the filler surface treatment. The stability of radicals determines to a great extend the adhesion of one composite to another, such as the adhesion of a luting cement to an inlay material.     

Serum ferritin determination: is it useful in the early diagnosis of renal carcinoma?

Highly filled luting resins are recommended for bonding porcelain restorations to tooth structure. This in vitro investigation was undertaken to determine the degree of cure of a 82 per cent filled dual-curing luting resin, after it was cured through various thicknesses of Cerec Vita Mark II porcelain. Infrared, as well as micro-Raman spectroscopy were used to determine the degree of cure of the cement at different time intervals after mixing and exposure to the curing light. The results indicated that Cerec porcelain thicknesses greater than 3 mm adversely affected the degree of cure of the luting resin, even at 24 hours after mixing the cement.     

How different curing methods affect the degree of conversion of resin-based inlay/onlay materials

The purpose of this investigation was to measure the conversion of five inlay materials with different curing methods. In particular, the influence of secondary curing in light ovens--that is, additional curing with light and heat simultaneously--was evaluated. The conversion was determined by infrared multiple internal reflection spectroscopy. The inlays were cured with three curing methods (A, B, and C). The conversion was recorded immediately after ended curing and after an additional storage period (postcuring). The mean conversion with method A, using a handheld curing unit, was 42.1% and increased significantly to a mean of 55.4% during the storage period at (37 +/- 1) degrees C. Both curing methods B and C, including the use of light ovens, gave a mean conversion of 65%, which did not increase significantly during the storage period. This investigation demonstrated that the degree of conversion depends on the curing method used.     

In vitro milling accuracy and fit of 'natural inlays'

OBJECTIVE: This study aimed to investigate the milling behaviour of natural inlays (NI) dental restorations constructed from sound extracted teeth. This was done by comparing the milling accuracy and fit of NI to those of industrial porcelain inlays (PI), milled in the same way. METHODS: A calibration pro-inlay was used to mill three NI and three PI. These were cemented in six acrylic cavities reproduced from the calibration mould, using composite luting cement. No etching and bonding were done. After storage for 24 h in water at room temperature the specimens were sliced buccolingually in a standardised way. For each specimen, two sections were photographed under a light-microscope, resulting in enlarged pictures of the sections. An acetate matrix with the measurement points was placed over each picture in a standardised way. The interfaces between inlays and moulds were measured at 13 fixed points per section using computerised image analysis software. The mean vertical- and floor-interfaces were calculated for each picture, and the overall means were found for each group. Confidence intervals were used for comparison of the differences. The profiles of the milled materials were examined using scanning electron microscopy. RESULTS: There were no differences between NI and PI in the mean interfaces (NI, 102 +/- 8 micrometers; PI, 107 +/- 8 micrometers). Electron microscopy revealed no apparent differences in the profiles of the milled surfaces. CONCLUSION: These findings indicate that the milling accuracy and the fit of natural inlays and milled porcelain inlays are comparable.     

Melanoma-associated hypopigmentation: where are the antibodies?

The purpose of this study was to compare the changes in the degree of conversion in the various layers of composites after additional heat curing. Four types of composites and three types of inlay ovens were used in this study. Composite was placed in a 4 mm thick Teflon mold and light cured from the top for 60 seconds. Twenty samples were prepared for each composite; 10 of these were additionally heat cured in an inlay oven as the manufacturer recommended. After light curing or light and heat curing, the samples were sectioned into four parts and assigned to groups A, B, C, or D according to their distance from the light source. These sections were then thinned to 50 to 70 mm, and these wafers were analyzed with a Fourier Transform Infrared spectrometer to determine the degree of conversion. A standard baseline technique was used to calculate the degree of conversion. When the composites were heat cured, significant increases in the degree of conversion were noted throughout the samples, but the amount of increase differed among materials. Thus the clinical performance of a heat-treated composite inlay may be different depending on materials.     

The rate of OH- ion release from lining materials containing calcium hydroxide

Four light-cured calcium hydroxide and three chemically cured resin-based lining materials were compared for hydoxil ion (OH-) release. Results indicated that the chemically cured calcium hydroxide cements were capable of OH- release for a longer period than the light-cured resin bases. Alkaliner (a chemically cured liner) produced and maintained the highest alkaline environment in the long-term, whereas calcium fluoride liner and Basic-L (both resin-based) showed the lowest values of OH- ion release.     

Mycosis fungoides palmaris et plantaris or acral pagetoid reticulosis?

Direct bonding of brackets has become a routine procedure in clinical orthodontics. Many techniques and materials are currently advocated and used, the most recent being light-cured composites. Advantages of the light-cured systems are their relative ease of use, improved bracket placement, and more rapid set of the composite. For a new system to be clinically viable, it must possess properties that are at least as reliable as existing systems. The purpose of this longitudinal clinical study was to evaluate and compare the rate of success and/or failure between a visible light-cured bonding material (Sequence) and a chemically cured bonding material (System 1+), using both systems in every patient. Contralateral quadrants were bonded with each system respectively. A total of 32 patients were followed for a mean period of 11 months (range of 3 to 21 months), with a total of 531 brackets bonded, 265 with visible light-cured and 266 with chemically cured resins. Failures for each system were recorded and failure rates calculated. The failure rate of the visible light-cured composite was 11.3% and that of the chemically cured composite was 12%. A Chi-squared (chi2) test did not reveal any statistically significant differences between the failure rates of the two systems, (chi2 = 0.014, df-1, P > 0.9).