Despite their many advantages, which include relatively low cost, RPDs have some major drawbacks. In particular, they can lead to increased ridge resorption, especially with appliances fabricated with non‐metallic bases, i.e., what are commonly known as “flippers.”
Whereas RPDs with polymeric (usually acrylic) clasps are somewhat “kinder” to supporting teeth, metallic clasps and rests will commonly traumatize the clasped teeth over time, notably causing wear and abrasion. This destructive action is due to clasps riding up and down the anchor teeth due to flexure of the RPD during mastication or parafunctional activities. Poor fit and/or repetitive vertical (and lateral) movements due to cyclic loading will not only exacerbate wear and abrasion of the abutment teeth but increase ridge resorption.
Another problem with RPDs, especially those with polymeric bases and poorly‐fitting appliances, is that food particles may often be trapped beneath the denture. This can lead to mucosal irritation, periodontal problems and, possibly, to decay of the supporting teeth. Further, staining of the acrylic “gum work” of the RPD as well as odor necessitates repeated and careful cleaning of the RPD on at least a daily basis to ensure a hygienic appliance and absence of halitosis. Depending upon diet and beverage consumption as well as smoking, there is often the need for more frequent cleaning of the RPD. Failure to remove the RPD and clean teeth and RPD separately compromises effective hygiene of both teeth and RPD.
There are, of course, some disadvantages to the use of implants to replace multiple teeth, Table 1.3.
Table 1.3 Disadvantages of implants vs traditional bridgework and RPDs.
| Short‐term cost is higher than for a traditional bridge or RPD Surgery is required Generally, treatment time is longer – 4–8 months. |
Implants vs Endodontic Treatment
Although general dentists receive training in endodontics during their education, many prefer not to provide root canal therapy, particularly when surgical intervention is required. There are several reasons for this reluctance to perform surgical endodontics, not the least is the general perception of patients that “root canal therapy” is an unpleasant, long‐drawn out procedure that can be uncomfortable at best and at worst is painful. In fact, to a great many patients, the words “root canal therapy” are synonymous with any procedure or experience that is to be avoided at almost any cost.
In contrast, non‐surgical endodontic treatment is a predictable treatment choice if certain conditions are met. First, there must remain enough sound tooth structure to achieve a 2 mm ferrule effect 360° around the tooth. This will ensure long‐term stability of restorative treatments. Secondly, a cause‐and‐effect should be established when diagnosing a symptomatic tooth. For example, caries approximating a pulp horn with symptoms lead to a clear diagnosis of irreversible pulpitis. Conversely, a symptomatic tooth with no caries present leads to a less predictable treatment outcome until and unless a definitive diagnosis can be achieved.
When there is need for “root canal therapy,” the operator must have available a specialized armamentarium of instruments and restorative materials. However, it must be stated that the available instrumentation and endodontic sealer cements have improved dramatically over the past 20 or so years. Further, it is generally recognized that the time and expertise required to perform endodontic surgery increases almost exponentially with the number of tooth roots/canals to be treated. Additionally, when canals are sclerosed or calcified, there is increased difficulty in ensuring a clean and extirpated pulpal chamber and root canals.
Finally, teeth that have received extensive endodontic therapy tend to embrittle over time and are subject to failure under loading. Further, it is difficult to achieve a complete hermetic seal of a root canal so that apical leakage and ingress of bacteria, blood and other matter into the treated canal can occur over time. Coronal migration of tissue fluids and bacteria leaking into the treated root canal over time can have many untoward consequences, including dentinal staining, breakdown of sealer cements and restorations, pain and discomfort as well as infection. Due to risks associated with endodontically treated teeth, dentists are often reluctant to use these teeth as abutments for both FPDs and RPDs.
In contrast, the success rate of dental implants is 95–97%. This is far higher than treatment of symptomatic teeth with marginal ridge fractures and endodontic retreatment. These success rates must be considered when discussing treatment options, particularly when relative costs, patient time‐commitment to treatment as well as patient discomfort are considered in addressing the question of root canal therapy vs placement of an implant.
Conclusions
Having presented the overall case for dental implants, specific factors regarding the placement and clinical application of implants will be covered in detail in the following chapters. Nevertheless, modern dentistry now recognizes that dental implants are the standard of care for prosthetic replacement of missing teeth. This is because they can readily and conveniently address some otherwise seemingly intractable problems in traditional restorative dentistry. Further, the advances in implant technology and dental science have progressed so markedly since the first days of the Brånemark concept that the outcome of dental implant placement has a success rate over 95%.
The final word should be that the ground‐breaking concept of Per‐Ingvar Brånemark has transformed dentistry and dental treatment for even the most challenging cases.
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