Establishing a classification system and criteria for veneer preparations

The concept of no- or minimal-preparation veneers is more than 25 years old, yet there is no classification system categorizing the extent of preparation for different veneer treatments. The lack of veneer preparation classifications creates misunderstanding and miscommunication with patients and within the dental profession. Such a system could be indicated in various clinical scenarios and would benefit dentists and patients, providing a guide for conservatively preparing and placing veneers. A classification system is proposed to divide preparation and veneering into reduction--referred to as space requirement, working thickness, or material room--volume of enamel remaining, and percentage of dentin exposed. Using this type of metric provides an accurate measurement system to quantify tooth structure removal, with preferably no reduction, on a case-by-case basis, dissolve uncertainty, and aid with multiple aspects of treatment planning and communication.

Minimum thickness anterior porcelain restorations

Porcelain laminate veneers (PLVs) provide the dentist and the patient with an opportunity to enhance the patient's smile in a minimally to virtually noninvasive manner. Today's PLV demonstrates excellent clinical performance and as materials and techniques have evolved, the PLV has become one of the most predictable, most esthetic, and least invasive modalities of treatment. This article explores the latest porcelain materials and their use in minimum thickness restoration.

Choice of ceramic for use in treatments with porcelain laminate veneers

Porcelain laminate veneers (PLVs) have been used for over two decades to treat esthetic and/or functional problems, particularly in the anterior sector. A range of dental ceramic materials are presently available on the market for these treatments, though with very different characteristics in terms of the composition, optic properties and manufacturing processes involved. As a result, selection of the material best suited for the management of each individual patient may prove complicated. The present study proposes a simple system for selecting the most appropriate ceramic material, based on the two variables that most influence the esthetic outcome: the intrinsic characteristics of the substrate tooth, and the characteristics of the ceramic material in terms of resistance and optic properties.

Crowns and other extra-coronal restorations: preparations for full veneer crowns

Preparations for full veneer crowns is the eighth in the series on crowns and other extra-coronal restorations. Whilst handpiece skills are important, many other factors combine to ensure provision of a satisfactory full veneer crown (also termed 'full coverage crown'). Our aim in writing this article is to consider the principles which influence crown preparation, seasoned with clinical advice our undergraduate and postgraduate students have found useful.

Direct restoration of anterior teeth: review of the clinical technique and case presentation

Direct composite resin bonding procedures are growing in popularity as conservative and predictable restorative treatment alternatives. An understanding of the fundamental layering, contouring, and polishing principles is paramount to the success of any direct composite restoration; this awareness can be subsequently applied to indirect restorations and significantly enhance laboratory/clinician communication. This article presents a clinical technique that describes the incremental placement of direct resin veneers on a typodont and demonstrates the application of these procedures on an actual clinical case.

Survival of three types of veneer restorations in a clinical trial: a 2.5-year interim evaluation

OBJECTIVES

In this clinical trial, 180 veneer restorations (VRs) were evaluated. The purpose of the study was to collect survival data and to find possible relations between survival and (1) 'type of VR', (2) 'preparation design', (3) 'operator' and (4) the patient-related variables 'tooth-type' and 'vitality of the tooth'.

METHODS

The restorations were provided by seven dentists in 1 12 patients on central and lateral maxillary incisors. Experimental variables were: 'type of VR' (either direct resin composite (DC), indirect resin composite (IC) or porcelain (P)), 'preparation design' (with and without incisal overlap) and 'operator'. Failures were recorded at two levels: absolute failure (need for new restoration) and relative failure (need for repair). Survival was defined at three levels: (1) survival of original restoration (Sr, endpoints: 'absolute' failures), (2) functional survival (Sf, endpoints: 'relative' failures) and (3) overall survival (SO, endpoints: both 'absolute-' and 'relative failures').

RESULTS

The variable 'type of VR' showed significant influence on Sf and So but not on Sr. Sf and So rates of P, IC and DC were, respectively: Sf-P, 94%; So-P, 94%; Sf-IC, 94%; So-IC, 90%; Sf-DC, 80%; So-DC, 74%. VRs on vital teeth showed a significantly better survival than VRs on non-vital teeth at all survival levels.

CONCLUSIONS

Preparation of the incisal edge for incisal coverage is considered to be unnecessary to assure or improve the strength of VRs. Veneers on non-vital teeth showed higher risk to fail than veneers placed on vital teeth. Porcelain veneers showed the best overall survival.

Recognition of veneer restorations by dentists and beautician students

Three types of veneer restorations (VRs) were evaluated for recognition by two groups of observers to study the aesthetic result. The different types of VRs were: porcelain, direct resin composite and indirect resin composite. One month after insertion of the VRs, colour transparencies were made of smiling patients randomly selected from a group of 112 patients participating in a clinical trial. The slides were evaluated by five dentists who were not familiar with the patients and by 25 beautician students (BS). Dentists were asked to locate the VRs which were present in the patients and to specify the type of VR. BS were only asked to locate the VRs. To trace a possible relationship between the aesthetic result of the treatment and a number of variables, ANOVA was applied to evaluate the variables: 'discolouration of the teeth' before treatment, 'type of VR' and 'number of VRs'. Agreements in judgement were expressed in Cohen-Kappa coefficients. The results showed that the dentists could locate the VRs quite well (Kappa coefficient 0.64 +/- 0.28) but for BS this was lower (Kappa coefficient 0.43 +/- 0.27). The more VRs were made in one patient, the more difficult it was to locate them correctly. The other variables had no significant effect on the recognition of the VRs. It was not possible for the dentist observers to differentiate between the types of VRs.

Shear bond strengths of resin luting cements to laboratory-made composite resin veneers

Retention problems have been reported with the clinical use of indirect microfilled resin veneers. This study used 24-hour shear tests to assess the bond strengths of such a resin veneer compared with other veneer types. The effect of different resin luting cements and resin veneer surface treatments were analyzed to elucidate factors by which retention could be increased. The six resin luting systems investigated showed a range of bond values. Debonding occurred primarily at the veneer/cement interface. G-Cera material produced the weakest bonds to Isosit-N resin. Surface treatment of Isosit-N veneers resulted in bond strength changes. Sandblasting reduced the force required for bond failure; Special Bond resin increased it slightly. Improving retention of prefabricated resin veneers proved difficult. Etched hybrid resin veneers delivered higher bond strengths than micro-filled resin veneers but not significantly. Etched porcelain veneers, however, provided consistently the strongest bond strengths with cohesive, as opposed to adhesive, bond failure.

Veneering of teeth. State of the art

Veneering of discolored, malformed, poorly restored, or broken-down teeth is now a reality in routine dental practice. Various types of veneers have been described. The most commonly used veneer has been described in detail. Properly placed veneers should provide patients with years of inexpensive, esthetic service. They are satisfying to dentists and patients, and their use should be encouraged.