Gordon J. Christensen

The use of porcelain-fused-to-metal restorations in current dental practice: A survey

The survey of members and guests of the American Academy of Esthetic Dentistry revealed the following: Porcelain-fused-to-metal crowns are the most commonly used crowns in dentistry, Cast gold crowns are infrequently placed compared to PFM, most dentists consider PFM crowns extremely successful restorations; although porcelain occlusal surfaces are considered acceptable by most dentists, dentists prefer metal on occlusal surfaces for restorations in their own mouths; the anterior 3/4 crown is infrequently placed, but the posterior 3/4 crown is commonly used; the Cerestore crown is gaining acceptance; Porcelain-jacket-crown use is reduced, but still a viable alternative; and the most desired improvement for PFM restorations was less wear on opposing teeth.

Is the rush to all-ceramic crowns justified?

There have been numerous obvious and unprecedented changes in the dental laboratory profession over the last several years. One of the most rapid changes has been the movement from handcrafted porcelainfused-to-metal (PFM) crowns and fixed prostheses to milled ceramic restorations. It is estimated that currently at least one-half of U.S. dental laboratories are providing in-house or outsourced milled crowns and fixed prostheses (B. Napier, chief staff executive, National Association of Dental Laboratories, written communication, Oct. 8, 2013). The most popular type of crown is ceramic without any metal substructure. The table provides comparative data for the years 2007 and 2013 as recorded for roughly 1 million units of crowns and fixed prostheses in the United States (J. Shuck, vice president for sales and marketing, Glidewell Dental Laboratories, written communication, Oct. 7, 2013). The most popular types of ceramic crowns in 2013, as recorded by Glidewell, were full-zirconia, zirconia-based (zirconia coping with ceramic fired or pressed on as a laminate) and lithium disilicate (IPS e.max, Ivoclar Vivadent, Amherst, N.Y.). For this article, I use the phrase “ceramic crowns” to indicate these three types, although several other types still are available. Other ceramic crowns constituted only a small percentage of the market in comparison with the three major types. The change from PFM to allceramic crowns over the past several years has been one of the fastest and most significant paradigm changes in the history of dentistry. In my opinion, some of the factors stimulating this shift have been dpublic demand for tooth-colored crowns; dobserved success of the current generation of all-ceramic crowns; dthe reduced laboratory costs for dentists for all-ceramic crowns; dthe high cost of metals used in PFM crowns, which motivate dentists to prescribe nonmetal crowns; dease of milling all-ceramic crowns when compared with fabricating PFM crowns; drapid growth and success of milling technology; dlaboratory acceptance of milling as state of the art.

MINI IMPLANTS: GOOD OR BAD FOR LONG‐TERM SERVICE?

Over 40 years ago, root-form dental implants made their major entry into clinical dentistry. The Swedish Branemark system, consisting of root-form titanium implants about 3.75 mm in diameter, made a major impact as dentists worldwide investigated and began to use these implants to support fixed/detachable prostheses for edentulous patients. The significance of implant placement and seating of a fixed/detachable prosthesis on the implants for edentulous patients was enormous.This critical appraisal deviates from our standard format to address a topic of great clinical interest but with relatively few published research studies.Over 40 years ago, root-form dental implants made their major entry into clinical dentistry. The Swedish Branemark system, consisting of root-form titanium implants about 3.75 mm in diameter, made a major impact as dentists worldwide investigated and began to use these implants to support fixed/detachable prostheses for edentulous patients. The significance of implant placement and seating of a fixed/detachable prosthesis on the implants for edentulous patients was enormous.

Periodontal surgery as an aid to restoring fractured teeth

The periodontal, orthodontic, and prosthetic management of four indications for subgingival or subosseous tooth fractures has been discussed. The importance of having the aveolar crest a minimal distance of 2.5 mm from the margin of the restoration has been explained. The pitfalls of an external, rather than internal, bevel and flap procedure were assessed. Coordinated interspecialty therapy provides diverse, conservative treatment for the general practitioner and successful restorations for the patient.

Rapid change in the fabrication of crowns and fixed prostheses

A significant change is occurring in fixed prosthodontics, and, in my opinion, there is no question but that it will continue. Many dental laboratories have closed in the past few years. According to the National Association of Dental Laboratories (NADL), approximately 5,000 laboratories closed in the period from 2006 through 2013, with 9,042 laboratories now functioning (Bennett Napier, CAE, chief staff executive, NADL, written communication, April 2, 2014). Why are dental laboratories closing? One reason is that laboratory owners cannot afford to upgrade their facilities to include expensive digital technology such as scanners, milling machines and the various accessory items. Another major reason is the significant percentage of crowns being made offshore. NADL estimates that approximately 34 percent of crowns currently placed in the United States have been made offshore (Bennett Napier, written communication, April 2, 2014). A third significant reason is the lowering of laboratory prices seen nationally and the inability of small dental laboratories to compete with the laboratories that are oriented toward mass production of indirect restorations. So what does the future hold in terms of the obvious major changes now going on in the fabrication of crowns and fixed prostheses? In this column, I will discuss the changes in fabrication of indirect restorations and the various steps necessary in the primary methods of fabricating restorations, as well as compare the potential influence each technique has on dental practices and the cost of each concept. This information should assist dentists attempting to make a decision about which of the methods of crown and fixed-prosthesis fabrication to use in their practices. The techniques and times I have listed in the following information are based on my long experience mentoring numerous conventionalfixed-prosthodontic study clubs and accomplishing research about scanning and in-office milling.

Operating gloves: The good and the bad

The use of gloves in all types of dentistry has been a major benefit to both patients and dentists. However, operating gloves are not without challenges. Tight ambidextrous gloves can produce significant and debilitating hand pain; latex allergies are a problem for many dental personnel and patients; and the disagreeable taste; odor and powder of some brands of gloves has frustrated both professionals and patients. In spite of the challenges that glove use poses, it offers many advantages--foremost among them the protection of patient and dentist alike from infection.

Dental continuing education in the aftermath of Sept. 11

The American people and our profession have been dealt a traumatic blow. The short-term effects of this incident are obvious: all aspects of our economy have slowed; travel and dental CE attendance are down; dentists are seeking other modes of CE that do not require travel. As the country recovers, I predict that dental CE will have a temporary lull, but that the desire for dental CE will continue to expand, and that the destination and local courses to which we have been accustomed will flourish again.

A HELPING HAND TO YOUTH

St John of God Director of Mission, Maureen Waddington, said that the service was able to assist vulnerable and marginalised people in Ballarat. “For the young people who come here, they find it gives them something to look forward to,” Ms Waddington said. She described it as, “a place where they can meet with others, where there is expert advice and above all respect for the journey of the person.”