Dental technology services and industry trends in New Zealand from 2010 to 2012.

OBJECTIVE: To provide a snapshot of the New Zealand dental technology industry and influencing factors. BACKGROUND: Developing an understanding of the commercial dental laboratory environment in New Zealand can provide insight into the entire dental industry. METHODS: A web-based survey was the primary method for data collection, with separate questionnaires used for dental laboratory owners and dental technician employees. RESULTS: The mean net income for dental laboratory owners in New Zealand was similar to that of the United Kingdom, at $40.50 per hour. Clinical dental technicians are the highest paid employees, with a mean of $33.49 per hour. The mean technical charge for complete dentures was $632.59; including clinical services, it was $1907.00. The mean charge for a porcelain-fused-to-metal (PFM) crown was $290.27. Dental laboratory owners expressed fear about the possibility of losing dental clients to overseas laboratories due to the availability and cheap charge of offshore work. Only 25.4% of dental laboratories surveyed had computer-aided design (CAD) facilities, and even fewer (7.9%) had computer-aided manufacturing (CAM) systems. CONCLUSION: Clinical dental technology appears to be prospering. The dental technology industry appears to be adapting and remains viable, despite facing many challenges.

Cost-effectiveness of endodontic molar retreatment compared with fixed partial dentures and single-tooth implant alternatives.

INTRODUCTION: One of the most challenging situations in dentistry is a failed root canal treatment case. Should a failed root canal-treated tooth be retreated nonsurgically or surgically, or should the tooth be extracted and replaced with an implant-supported restoration or fixed partial denture? These four treatment alternatives were compared from the perspective of cost-effectiveness on the basis of the current best available evidence. METHODS: The costs of the four major treatment modalities were calculated using the national fee averages from the 2009 American Dental Association survey of dental fees. The outcome data of all treatment modalities were retrieved from meta-analyses after electronic and manual searches were undertaken in the database from MEDLINE, Cochrane, ISI Web of Knowledge, and Scopus up to April 2010. The treatment strategy model was built and run with TreeAge decision analysis software (TreeAge Software, Inc, Williamstown, MA). RESULTS: Endodontic microsurgery was the most cost-effective approach followed by nonsurgical retreatment and crown, then extraction and fixed partial denture, and finally extraction and single implant-supported restoration. CONCLUSIONS: The cost-effectiveness analysis showed that endodontic microsurgery was the most cost-effective among all the treatment modalities for a failed endodontically treated first molar. A single implant-supported restoration, despite its high survival rate, was shown to be the least cost-effective treatment option based on current fees.

The effect of veneers on cosmetic improvement.

OBJECTIVES: This clinical study was designed to compare the patient's opinion of the cosmetic improvement after the placement of direct composite and indirect porcelain veneers. METHODS: This retrospective study involved a survey of 145 patients (96 responses) each treated with 10 direct composite (Vitalescence) or 10 porcelain (Fortress) veneers. Patients subjectively evaluated multiple aspects of their smile using visual analogue scales before and after treatment for colour, shape, size, smile line and overall facial appearance. RESULTS: There were no statistical differences between the cosmetic improvement achieved for porcelain and composite (p > or = 0.05). Cost factors were not significant. Significant factors were: tooth conservation (p < or = 0.021), time (p < or = 0.012), repair costs (p < or = 0.009) and replacement costs (p < or = 0.024) and favoured the direct composite veneers over the porcelain veneers. Correlation findings relating to what patients feel as the key components of the smile for overall cosmetic improvement showed medium to high correlations (0.301 < or = r < or = 0.718) with tooth shape, colour and level of tooth display, gingival level, gingival symmetry and tooth whiteness. CONCLUSION: The choice of material (direct composite resin vs porcelain) when constructing maxillary anterior veneers does not significantly affect the patient's perception of cosmetic improvement. However, there was a preference towards accepting the composite veneer option. Overall aesthetic satisfaction is multifactorial. The results support the opinion that the more conservative composite veneers are justified and that, given the choice and information, patients may prefer this option.

All-ceramic single-tooth restorations: choosing the material to match the preparation--preparing the tooth to match the material.

The shape of a crown preparation is the prime determinant for the choice of material for an all-ceramic restoration. One essential factor is the available space for the restoration, which requires a certain occlusal thickness. The dentist's preparation design determines the available vertical clearance, and the dental technician has the responsibility of advising the dentist with regard to either choosing the right material to match the preparation or to preparing the tooth to match the material. Assuming a minimum static fracture strength of > 2000 N, the following materials can be used for all-ceramic crowns: Laboratory surveys have shown that in most situations, the available occlusal clearance in clinical reality is only 0.8 to 0.9 mm (after cementing). This shows that the available space will often be insufficient for providing monoblock crowns and still on the tight side for veneered oxide ceramics (In Ceram, zirconia, etc.). However, crowns made of veneered oxide ceramics are much more complex to fabricate and much more expensive. By simply providing a minimal occlusal thickness of 1.5 mm, the treatment provider could therefore easily facilitate the use of the much more economical monoblock crowns without compromising either esthetics or strength. Actually, crowns with veneered oxide ceramic copings do not offer any higher fracture resistance compared to Mark II crowns as long as the minimum thickness requirements are met. The flexural strength of CAD/CAM-fabricated lithium disilicate rods is about twice that of CAD/CAM-fabricated Mark II rods. When used for crowns with a wall thickness of 1.5 mm, however, both materials exhibit the same fracture strength of between 2000 and 2500 N. This is related to the different reinforcing action of the adhesive luting agent, which is essentially required for both these materials. When choosing a material, preparation shapes, technical complexity and cost should be thoroughly compared and scrutinized and should figure prominently in the discussions between dentists and dental technician. Unfavorable preparation shapes for single crowns will necessitate compromises in terms of the choice of materials that result in high cost but do not offer anything in the way of higher fracture resistance. What constitutes an appropriate all-ceramic restoration for a single tooth? Do all-ceramic single crowns require the same material bulk as multi-unit bridges? Everything would indicate that a suitable preparation geometry allows feldspathic ceramic monoblock crowns to be milled that do not require any extensive finishing efforts such as thermal annealing or in-laboratory veneering while at the same time demanding no compromises in terms of esthetics and load-bearing capacity.