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The ultimate esthetic dentistry takes into account the conservation of healthy tooth structure integrated with biologic and long-term functional requirements. Materials and techniques that address these inseparable issues are necessary for true excellence. One such material has been presented for the fabrication of porcelain veneers without the need for overt tooth destruction to create masking ability and without an unsightly opaque appearance.
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UNLABELLED: The use of composite resin restorations in posterior teeth has increased considerably in the past few years. Specific composite resins for posterior teeth, as well as new operative techniques, have been developed to overcome some clinical difficulties. The present article describes a new technique to reconstitute the interproximal contour and contact of Class II restorations using a packable composite resin. Two lower first molars from the same patient are reported in detail, illustrating the technique step by step. The technique indicates the use of a metallic matrix band and wood wedges to provide an interproximal contour and contact with the adjacent tooth as well as to provide an adequate cervical adaptation. The first increment of the packable composite resin is applied on the gingival wall of the proximal box, packed cervically near the axial wall and, automatically, the resin climbs up in contact with the inner surface of the matrix band. This increment is sculpted and light-cured and the metallic matrix band is removed. Thus, the Class II cavities are transformed into Class I, with free access for light-curing. Small incremental layers of composite fill the remaining cavities. This technique is faster than conventional techniques and permits appropriate embrasure, better contour, and contact points. CLINICAL SIGNIFICANCE: Packable composite resins present primarily new handling characteristics that permit the development of novel filling techniques. The technique proposed in this article allows easier Class II buildup, with proper proximal contact and proximal smooth surfaces, once there are no irregularities among the composite increments. Another advantage is that there is adequate light exposure for polymerization, because the metal matrix can be removed during the restorative procedure.
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An increasing number of patients with complete dentures are requesting improvements in the aesthetics of their dentures. This paper considers methods of improving aesthetics, using the information available from the existing complete dentures, pre-extraction records and resin stains.
The problem of toothwear appears to be increasing in both children and adults. Recent developments in bonding and aesthetic restorations have added to the dentist's armamentarium for restoring worn teeth. Bonded ceramic and composite restorations offer the possibility of conservative restoration of teeth already damaged by toothwear. Despite this, concern still remains regarding the durability and clinical performance of these restorations. This paper reviews the currently available techniques for providing tooth-coloured restorations in toothwear cases.
A number of techniques involving the use of various instruments, brushes and devices have been described for the removal of excess luting material and subsequent finishing around the margins of indirect tooth-coloured restorations. There is little information available on the clinical techniques employed by UK dental practitioners in the placement of these restorations, or on the effectiveness of these techniques. A questionnaire was designed to elicit such information. This was distributed to 500 UK-based dental practitioners. A total of 301 practitioners returned completed questionnaires, giving a response rate of 60%. The results indicated that 88% of the respondents routinely provided porcelain veneers for their patients, with 94% of these respondents indicating that they routinely prepared teeth during the provision of such restorations. A light-cured resin composite luting material was used by 29% of the respondents in placement of veneers, while 69% used a dual cured composite. Excess uncured luting material was removed by a number of methods and a variety of methods were used by respondents to finish the margins of the veneers after placement. Of the respondents 68% indicated that they routinely provided tooth-coloured inlays and onlays, with 89% indicating that they routinely used a dentine bonding system when luting their indirect tooth-coloured restorations. It is concluded that a high proportion of the practitioners surveyed were providing porcelain veneers and tooth-coloured inlays and that a wide variety of materials and finishing techniques were being used.
Compomers, resin-modified glass ionomers, were developed to improve the physical properties and clinical handling of glass ionomers. Compomers can be designed to be light-activated and used as restoratives or liners. This article reports data collected up to 12 months after placement of both compomer restorations and liners and is part of an ongoing study evaluating the performance of this material. Based on this data, the authors conclude that this new generation of light-activated glass-ionomer restoratives provides clinical results comparable to those recorded for composite resins at 12 months.
BACKGROUND: Prosthodontics is the dental specialty responsible for diagnosis, rehabilitation and maintenance of patients with complex clinical conditions involving missing or deficient teeth and/or craniofacial tissues. The essence of the specialty is expert treatment planning. OVERVIEW/LITERATURE REVIEWED: In recent years, new approaches and technology have been introduced as a result of research performed in universities and by industry. The field of prosthodontics continues to evolve owing to a better understanding of the biology of the oral cavity and the introduction of new techniques and improved biomaterials. Improvements in periodontal and oral surgical techniques, implant procedures and materials, esthetic restorative materials, and jaw tracking recorders and articulators have led to enhanced functional and esthetic oral and maxillofacial prostheses. CONCLUSIONS AND CLINICAL IMPLICATIONS: The complexities of today's technical and clinical procedures and the higher expectations for more esthetically pleasing dentistry by the general patient population have placed a premium on teamwork involving general dentists, specialists and dental technicians.
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This study investigated the effect of intrinsic pigmentation on the transverse strength of a microwave-cured acrylic resin. Forty transverse strength specimens were fabricated according to ADA specification #12 and divided into 5 groups. No fibers were added to group I (GI, control group); acrylic stain (AS) was added to GII and GIII in concentrations of 0.5 and 1.5% w/w, respectively; acrylic fibers (AF) were added to groups GIV and GV in concentrations of 0.5 and 1.5% w/w, respectively. All specimens were irradiated in a microwave oven with a cycle of 3 min at 360 W, followed by 4 min resting, then 3 min at 810 W. Flasks were bench-cooled for 30 min at room temperature, followed by immersion in cold tap water for 30 min. After storage in distilled water at 37 degrees C for 48 h, all specimens were tested for flexural strength in a testing machine (EMIC-DL 500) at a crosshead speed of 0.5 cm/min. Mean and standard deviation (MPa) for the flexural strength test were: GI = 86.0 +/- 7.9; GII = 86.0 +/- 9.8; GIII = 86.6 +/- 7.7; GIV = 84.9 +/- 5.3; GV = 84.9 +/- 5.2. No statistical differences were detected among the groups (ANOVA, p > 0.05). The addition of the acrylic fibers or the acrylic stain did not affect the transverse strength of the microwave-cured acrylic resin.
This randomized clinical trial was initiated to study the effect of two restorative procedures on the clinical quality and longevity of class-III resin restorations. The material consisted of 52 pairs of class-III restorations in the microfilled resin Silar completed with two modifications of the conventional acid-etch restorative procedure: A) beveling of the margins of the cavity preparations, and B) treatment of the etched butt-joint cavities before filling with the dentin-adhesive NPG-GMA/ethanol together with re-etching and surface coating of the finished restorations with low viscous resin. The restorations were examined at base line and after 2, 4, 6, and 11 years. The cumulative 11-year survival rate for both types of restorations was 84%. Marginal discolorations, marginal discrepancies, and secondary caries were most often recorded corresponding to the beveled type-A restorations, whereas the esthetic quality of the two types of restorations was almost identical. Surface discolorations were most often recorded among smokers, and significant correlations were found between the patients' consumption of alcoholic beverages and corpus discoloration, surface discoloration, and surface wear of restorations.
The fungal discolouration of silicone rubber prostheses is reported in four cases. In two of the cases, the discolouration was caused by the fungus Candida tropicalis. In the other two cases, two different fungal organisms, namely Trichoderma sp. and Scedosporium prolificans were incriminated. The non-porous silicone rubber layers create an enclosed environment in the suction cup of the prosthesis and preclude ventilation at the prosthesis-stump interface. The moisture as a result of sweat and body warmth in the stump assists fungal growth. Residual salts from the sweat, sebum from sebaceous glands and the residues from petroleum jelly (Vaseline) applied to facilitate donning, can adhere to the surfaces of the prosthesis and provide the nutrients for fungal growth. Prolonged continuous usages of the prosthesis, the presence of sweaty palms in the users, donning the prosthesis during manual physical activities which induce perspiration, washing of hands with the prosthesis on and warm humid climatic conditions have been identified as factors predisposing the prosthesis to fungal colonisation. The fungal growth caused a black discolouration and marred the aesthetic quality of the prostheses. As a preventative measure, daily immersion of the prostheses in denture cleaner such as benzalkonium chloride, or water at 60 degrees C for 15 minutes, or decontamination with 70% alcohol is recommended. Prior cleaning to remove organic matter before decontamination is emphasised.
This study looks at the effect of metamerism in colour-matching and the assessment of multi-layered silicone rubber finger prostheses. The aim was to identify the choice of illuminants for colour matching the prostheses that would give rise to the least metameric effect between the prostheses and the human skin or the best colour match. The prostheses were prepared and colour matched to a fair-skinned subject under 3 reference illuminants--TL84, D65, F and a combination of illuminants--TL84, D65 and F. The prostheses were then measured for colour using a spectrophotometer based on the CIE indices L*, a*, b* with each prosthesis assessed separately against the subject's index finger under the reference illuminants--TL84, D65 and F. The prostheses were also assessed by a panel of 50 observers and scored according to colour-match. Colour differences between the skin and prosthesis were measured in the illuminant under which the prostheses were prepared and then under the other reference illuminants. A relationship was obtained between the measured mean colour difference, deltaE*, and the mean visual assessment score for each prosthesis. This paper points out the concerns related to the optical phenomenon of metamerism with the colour pigments used. This can affect the colour match of the prosthesis as perceived by the patient. The findings seem to suggest that this metameric colour difference can be minimised if the prosthesis is matched under a combination of lights, which were found to give the best-perceived match.
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Differential scanning calorimetry was used to evaluate the effects of polymerizing conditions and the addition of pigments for a heat-activated maxillofacial silicone (MDX 4-4515). Unpigmented specimens were examined in the starting condition and after polymerizing at 100 degrees C for 1 hour, 4 hours, and 20 hours, and specimens of four different pigmented silicones processed 1 hour at 100 degrees C were also included. The DSC scanning was performed from -150 degrees C to 200 degrees C at 10 degrees C per minute, and a strong melting-recrystallization peak at approximately -40 degrees C was found for all eight specimen groups (N = 5). Modulated differential scanning calorimetry resolved this peak into separate melting and recrystallization peaks, and confirmed the existence of a very weak glass transition peak in this silicone at approximately -125 degrees C. The mechanical properties of the MDX 4-4515 silicone appear to be dominated by melting and recrystallization, rather than the glass transition, and differences may exist in the viscoelastic and creep behavior for the unpigmented and pigmented materials.
One significant challenge in aesthetic dentistry is to integrate individual restorations with the adjacent natural dentition. In order to achieve a seamless result postoperatively, the clinical preparation and the laboratory fabrication phases of treatment must be performed in concert. The use of ultraconservative laminate veneers is a restorative modality that permits the development of a functional, aesthetic outcome while preserving the greatest degree of natural tooth structure. This article highlights the preparation design and material considerations that are involved with ultrathin porcelain laminate veneer restorations.