Sixty Years of Evolution in Dentistry - Dentistry Today

2022-06-25 04:22:25 By : Ms. FeiFei Zhong

Guidelines for Cementing or Bonding Ceramic Restorations

Guidelines for Cementing or Bonding Ceramic Restorations

Drs. Gordon and Rella Christensen

What has changed in dentistry over the last 60 years? Is the profession the same as it was 60 years ago, slightly different, or changed significantly? The answer to the question, answered by 2 practitioners who have lived and practiced through those 60 years, is that dentistry hardly resembles what it was 60 years ago, and the changes are predicted to continue and expand!

To facilitate easy reading and allow comparisons of dentistry 60 years ago with dentistry today, the article is divided into the following sections:

In 1962, dentistry was mainly treatment-oriented, but there were observable changes toward preventive concepts, including fluoride in toothpaste, 6-month exams, diet, and the necessity for adequate oral hygiene.

Dentists were primarily male. The necessity of oral care observed during the First and Second World Wars thrust dentists and dental care into public observation and acceptance. Dentists became highly respected by the public as “doctors of dental surgery” (DDS) and were considered to be honest, trusted professionals. Almost all dentists were in individual private practice, with a few group practices beginning to be formed. Most dentists had at least one dental assistant. Four-handed dentistry was beginning to be promoted. Expanded clinical tasks for auxiliaries were very few, and most expanded functions now popular were then illegal. 

Professional dental societies were dominant and powerful. Dentist advertising was considered to be unethical, and even having the dentist’s name in letters larger than 2 inches high on the office door or window was not permitted. The “washed field” technique, ushered in by Dr. Elbert Thompson, started a new clinical paradigm requiring high-velocity suction systems. Belt-driven clinical handpieces were being replaced by air rotors. A few companies pioneered electric handpieces, which did not become popular until many years later.

Looking back on this described scenario makes dentistry in 2022 look like a different profession.

Operative dentistry was the mainstay of dentistry. When patients thought of dentists, their initial conclusions were dentists do “fillings” in teeth to fill “cavities.” Operative dentistry techniques were the main involvement of most dentists, including the use of silicate cement for anterior teeth and amalgam for posterior teeth (Figure 1). Acrylic resin restorations were available for anterior teeth, but they soon discolored and leaked. Cast gold alloy and gold foil restorations were infrequently accomplished and mainly for the affluent. Porcelain-fused-to-metal (PFM) was just beginning to be available and mostly had feldspathic ceramic fused over base metal.

Dental hygiene education was a respected 4-year educational program in many universities. Often, dental hygiene students were taught in the same basic science classes with dental students. The importance of oral hygiene, stimulated by the military services and emphasized by professional hygienists, made significant inroads into the dental profession.

Crown and bridge (fixed prosthodontics) procedures were accomplished frequently, usually using cast gold alloy restorations cemented with zinc phosphate cement. PFM was in its infancy (Figure 2). Porcelain jacket crowns cemented with zinc phosphate cement served relatively well but were weak. Many dentists accomplished their own laboratory work. Functional acceptability was the rule for all restorations, with aesthetics being secondary—three-quarter crowns were common, showing gold frequently when smiling.

Removable prosthodontic procedures were commonly accomplished with only minimal concern for retaining teeth that today would be identified as restorable. Complete dentures resembled the dentures of today. They were polymethyl methacrylate (PMMA) with primarily porcelain denture teeth. Vulcanite rubber dentures, an invention from the 1840s, had nearly vanished but were seen occasionally. Removable partial dentures usually had metal frameworks, with “flippers” made of PMMA also available.

Dental radiology was analog, requiring developing and fixing of film in a dark room. Radiation was extremely high compared to the digital radiographs of today. The analog radiographs had high contrast, often showing initial caries much better than the digital radiographs of today.

Oral surgery accomplished by general dentists was primarily tooth extraction with necessary bone contouring. Sacrificing bone to expedite teeth removal was the common practice and would be considered extensive and overdone by the standards of bone conservation today.

Orthodontic treatment was infrequently accomplished by the standards of today when, currently, most adolescents receive orthodontic treatment. Premolar extraction techniques were common. Many orthodontic specialists made treatment advancements that are still practiced today.

Endodontics, pediatric dentistry, and periodontic procedures were evolving but primitive by the standards of today. Aesthetic dentistry did not emerge until the 1970s.

At least 12 other identifiable dental preventive and treatment subjects have evolved and become part of dental practices since 1962. 

The ADA has nearly 70% of dentists as members and offers some significant benefits to them. Some of the ADA statistics follow.

It is obvious that advertising and an overpopulation of dentists have caused significant competition among practitioners in many areas of the United States.

While the majority of dentists in 1962 represented the definition of a true professional person, the dentists of 2022 have been forced by competition to become business-oriented and still maintain a professional orientation.

There have been virtually hundreds of significant paradigm shifts in dentistry since 1962. An entire book would be required to enumerate and describe them. Next, we’ll briefly dicuss the current acknowledged specialites and other significant categories of dentistry. 

The following topics represent the major and most significant changes since 1962. They are not prioritized, and they represent many areas of dentistry. Since 1962, the majority of the currently 12 ADA-approved dental specialties have evolved. A dental specialty is an area of dentistry that the National Commission has formally recognized based on compliance with the Requirements for Recognition of Dental Specialties. The 12 ADA-recognized specialties follow: 

The following topics are related to major paradigm changes that have been introduced over the past 60 years. They are not listed in a prioritized order. 

In recent years, the concept of DSOs has continued to evolve and enlarge in the profession. There are now hundreds of these organizations, the largest of which are Aspen, Heartland, and Pacific. They are very attractive to young practitioners because it is almost impossible to start a practice alone. They also appeal to some mature practitioners who are ready to eliminate the challenges of the business aspects of practice. The advantages and limitations of such practices are a subject of significant debate. However, the fact is they are here and growing. Some practitioners find working in a DSO desirable, while others find the concept questionable. Many personal situations dictate these feelings.

Managed care, presented by dental insurance companies, has become commonplace in dentistry. Most dental practices find themselves  involved with these companies in some manner. The companies have allowed some patients who would not otherwise been able to have dental treatment to obtain dental services, but the companies have also  been criticized for dictating fees and policies for the dentist participants. This concept, both good and bad, has been identified in surveys as one of the most frustrating issues facing dentistry today.

In 1962, the removal of teeth was commonplace. Now most dentists, with a few exceptions, attempt to save natural teeth, if at all possible.

The use of root form implants has been among the most major paradigm changes in the history of dentistry (Figure 5). However, the now-proven development of peri-mucositis and peri-implantitis around implants after several years of service has made dentists cautious about removing natural teeth that can be restored. More education, as well as many patient factors, must be taken into account to ensure a high success rate. With this explosion, we are seeing literally hundreds of root form implant companies. Their placement has expanded from only the specialists to also the general practitioners, making this procedure more available to the general population. 

A majority of American and Canadian dentists use air rotor handpieces, which were introduced in the early 1960s. This type of handpiece was another major paradigm change from belt-driven handpieces. Midwest has long-been the most popular brand, but Star, KaVo, Bien-Air, and others are also excellent brands.

For years, amalgam and silicate cement dominated direct restorative materials. Later, glass ionomers and resin-modified glass ionomers became available. The current generation of user-friendly conventional glass ionomers has provided excellent cariostatic effects and easier use, eg, EQUIA Forte (GC) and Ketac Universal (3M).

For many years, various inventors and companies have worked on numerous ways, from simple to complex, to create digital impressions of tooth preparations as well as being able to mill restorations in clinical offices. Most became discouraged and abandoned the projects, but M. Brandestini and W. Mormann persisted, and the result was the CEREC system (Dentsply Sirona) for making digital impressions and designing and milling restorations (Figure 6). Many companies have since used this foundation, and the process has evolved over the years. This concept has had a significant influence in the profession for the current practitioners.

Three-dimensional printing is a concept that is still emerging in the dental profession. It allows the scanning, designing, and printing of study models, occlusal splints, provisional restorations, and many other objects. This concept is used by most dental laboratories, but it is just beginning to be used in some dental offices with products such as Form 3 (Formlabs) and SprintRay Pro (SprintRay).

Many companies produce digital scanners (eg, Primescan [Dentsply Sirona] and Emerald Scanner [Planmeca]), which are used in about 20% of clinical offices and in almost all dental laboratories for many dental procedures. It is anticipated that this concept will gradually replace the now-standard elastomer impression materials.

In just one decade, the production of crowns and fixed prostheses has changed from metal (PFM or cast gold alloy) to about 90% ceramic (zirconia and lithium disilicate) (Figure 7). This has been one of the fastest paradigm changes in the history of dentistry. The new ceramic materials, including BruxZir (Glidewell) and IPS e.max (Ivoclar Vivadent), are stronger than the many previous ceramic restorations, many of which failed clinically soon after placement.

About 40% to 50% of adults in the United States snore due to many factors, including sleep apnea. According to the ADA, dentists see about 70% of adults in the United States at least once per year, while physicians see their patients much less frequently. Thus, dentists are the logical practitioners to diagnose and treat patients with these issues. Dentists know dental occlusion and dental laboratory procedures, and they interact with dental laboratory technicians. This field is growing rapidly and is a significant paradigm change for the dental profession.

The COVID-19 pandemic produced a resurgence of interest in infection control in dental offices. Many conflicting suggestions were made by public health officials and politicians. In recent years, dental clinicians have led in infection control for outpatient offices. During the height of the pandemic, dental offices were noted to be among the safest places. Even pre-COVID-19,  infection control was at extremely high standards and now continues to be at the forefront. Looking at our retrospective, the current procedures for infection control in dental offices are certainly completely different and more adequate than they were in 1962.

Most dental patients want tooth-colored restorations, and the previous concept of long-term service necessity has been replaced by aesthetic acceptability. Unfortunately, this change has often brought the need to replace restorations more frequently, but the aesthetic trend initiated in the 1980s is clearly going to be increased in the future as the use of metal for dental restoratives is reduced.

Unfortunately, typical physical exams by physicians seldom include a thorough examination of the mouth. Dentists see patients on a routine basis, and hygienists are also trained in these exams. Seeing most patients at least twice per year, more than our medical brethren, allows a better chance for early detection of oral cancer. The dental profession is the only guardian of the oral cavity. Numerous screening devices, such as VELscope Vx (LED Dental) and Identafi (DentalEZ), are available that provide the ability for dental professionals to screen for oral cancer in addition to what they’ve learned about early detection from continued education.

In 1962, the majority of removable partial dentures (RPDs) had a metal framework with acrylic or ceramic teeth attached to it with an acrylic, gingival-colored base. Now surveys show that a high percentage of RPDs do not have a metal framework and about 70% of dentists are using flexible materials at least some of the time. Flexible partial dentures are made from thermoplastics (nylon, plastics, and some acrylics). These partials are preferred by patients, but they have some limitations, such as settling into the soft tissues, because of their flexibility.

Clinical tasks assigned by dentists to dental assistants, dental hygienists, laboratory technicians, and dental therapists have grown markedly. Such assignments allow more service and more revenue but must be supervised very carefully to ensure the delivery of quality care. 

The internet has provided an enormous amount of information for dental professionals that is available in seconds. This form of communication is perhaps the most major of all paradigm changes affecting dentistry over the last 60 years.

Has dentistry changed in the last 60 years? A better question is “What has not changed in dentistry?” Our profession has come of age. It is an essential part of health care. There are about 200,000 dentists in the United States and about 1,000,000 physicians. Dentistry is the largest specialty of all medicine! The changes in dentistry over the last 60 years are impressive, and the future shows the promise of even more changes that will positively influence our ability to better serve the public.

Dr. Gordon Christensen is founder and CEO of Practical Clinical Courses (PCC); CEO of Clinicians Report Foundation (CR Foundation); and a practicing prosthodontist in Provo, Utah. He and Dr. Rella Christensen are cofounders of the nonprofit CR Foundation (previously Clinical Research Associates [CRA]). Since 1976, they have conducted research in all areas of dentistry and published the findings to the profession in the well-known CRA Newsletter, now called Clinicians Report. Dr. Christensen received his DDS degree from the University of Southern California, his MSD from the University of Washington, and his PhD from the University of Denver and has received 2 honorary doctorates. Early in his career, he helped initiate the University of Kentucky and University of Colorado dental schools, taught at the University of Washington, and was the original dean of the Scottsdale Center. Currently, he is an adjunct professor at the University of Utah School of Dentistry. He is a member of numerous professional organizations. He can be reached at info@pccdental.com.

Dr. Rella Christensen is the director of TRAC Research Laboratory, which is devoted to clinical research in oral microbiology and dental restorative concepts. TRAC Research is part of the nonprofit, educational CR Foundation, which she directed for 27 years. Throughout her career, she has taught at the undergraduate and postgraduate levels, authored many research abstracts and reports, and received numerous honors. She has performed research within the practices of hundreds of dentists and their teams seeking the best patient treatments. She can be reached via email at rella@tracresearch.org.

Disclosure: The authors report no disclosures.  

Avatar DentistryToday @dentistrytoday · 23 Jun Ten @ 10 – Henry Schein Digital Solutions FastPass for Dentsply Sirona World 2022 https://www.dentistrytoday.com/ten-10-henry-schein-digital-solutions-fastpass-for-dentsply-sirona-world-2022/ Twitter 1540107433707655169

Ten @ 10 – Henry Schein Digital Solutions FastPass for Dentsply Sirona World 2022 https://www.dentistrytoday.com/ten-10-henry-schein-digital-solutions-fastpass-for-dentsply-sirona-world-2022/