When the Most Conservative Treatment Might Not Be the Most Appropriate Treatment
For years “minimally invasive” has been the watchword of clinical dentistry. In abstraction, it is unarguably the guiding principle of ethical treatment planning. But no plan survives its first contact with the enemy, and clinical reality regularly presents situations where a minimally invasive approach is either impossible or even deleterious to long-term success. Inside Dentistry takes a look at the quandary of practicing minimally invasive dentistry when “ideal” meets “get real.”
The Minimally Invasive Model
The principles of minimally invasive dentistry aspire to preserve the maximum amount of natural tooth structure when modifications are required, and replace it so that it mimics what was removed. A different paradigm from when GV Black espoused “extension for prevention,” minimally invasive dentistry as the presumptive standard of care evolved coincidentally as retention form principles could be eliminated, resistance forms could be diminished, and clinicians were presented with more options.
“If GV Black had our technologies, materials, and techniques, he’d have been practicing minimally invasive dentistry; he did the best he could with the materials he had,” says Mark Malterud, DDS, trustee of the Academy of General Dentistry and former officer of the Academy of Biomimetic Dentistry.
It’s generally agreed that the full thrust of more conservative treatment began with the advent and evolution of adhesive technology initiated with the introduction of etching enamel by Buonocore, explains Michael Sesemann, DDS, an Accredited Fellow and past president of the American Academy of Cosmetic Dentistry (AACD). With the evolution of composites and porcelains, restorative materials could be bonded to tooth structure, rather than mechanical retention. They also didn’t need to be thick and bulky for strength, as illustrated by bonding thin porcelain veneers to enamel from their advent in the 1980s to their zenith in the late 1990s through the first decade of the 2000s.
“Within one generation of dentistry, the landscape changed profoundly,” he notes.
The concepts spread to restorative dentistry, and instead of eliminating an entire occlusal surface for a metal restoration and implementing “extension for prevention,” dentists could remove only the area of decay, clean the remaining adjacent fissures, and restore the entire preparation with a methacrylate-based composite material; one formulation for larger cavities and a lower-viscosity material to conservatively infiltrate and seal the grooves.
“I don’t think any dentist is a maximally invasive dentist,” says Malterud. “More people are embodying the minimally invasive philosophy, which preserves as much tooth structure as possible, then builds the tooth back up to restore strength using today’s technology, techniques, and materials to where it can function.”
Essentially, restorative materials have evolved from occupying space to “fill” a void in a tooth to being bioactive, remineralizing, and protective. According to James DiMarino, DMD, MSEd, director of clinical affairs for Premier Dental Products Company, materials can be considered “minimally” invasive or conservative if the decay they are used to replace is itself minimal. However, the only way decay can be minimal is if patients are using technology in conjunction with effective home care to prevent or reduce the progression of decay.
For cosmetic dentistry, minimally invasive concepts have come full circle since their early years, when composite bonding and bleaching were the main options available, explains Corky Willhite, DDS, an Accredited Fellow of the AACD and former member of the American Board of Cosmetic Dentistry. When porcelain veneers became popular, there was a trend away from being conservative, with more aggressive preparations accommodating the reduction required for porcelain build-ups. AACD Accreditation examiners were among the first to reverse this trend with guidelines discouraging aggressive preparations.
“The pendulum has swung back toward composites and conservative dentistry,” Willhite observes. “This has been reinforced with the advent of prepless porcelain veneers and biomimetic dentistry.”
This follows general trends in medicine, where minimally invasive procedures are preferred. Fortunately for dentists, adhesive materials and porcelain fabrication techniques have improved greatly in recent years, allowing for very thin, strong ceramics that can be bonded with high predictability. Aggressively removing tooth structure is no longer warranted or desired.
“Better informed and educated patients seek treatments that are not only esthetic, but are also innocuous, healing, and have a beneficial effect on their overall health,” notes Lynne Calliott, vice president of marketing, Americas, for Shofu Dental Corporation. “Minimally invasive dentistry is associated with thinking about a patient’s condition in a holistic versus atomistic way.”