The Tipped Mandibular Molar as a Bridge Abutment: Part I
Avishai Sadan, DMD
The mandibular first molar is one of the first permanent teeth to erupt, and, in many instances, it is also the first tooth to be extracted. As a result, the placement of a three-unit fixed partial denture (FPD) is often required to restore the edentulous space. Years following the extraction, many patients request or receive a treatment plan that includes the restoration of this missing tooth. Due to the years intervening between the extraction and the restoration, however, the ridge may be resorbed with a significant loss of vertical bone, the adjacent teeth may be restored, and the second mandibular molar may be tipped mesially. In such instances, implant treatment-planning can be extremely complicated. It is a challenge, however, that can be addressed by the three-unit FPD. This presentation will discuss treatment alternatives and guidelines for the utilization of the tipped molar as a bridge abutment. Herein, the indications and rationale for orthodontic uprighting are presented.
Traditionally considered an ideal treatment plan, several advantages and disadvantages are associated with the orthodontic uprighting technique. The advantages of orthodontic uprighting are easy preparation design, elimination of pseudopockets,1 and the minimization of mesial periodontal defects. In addition, occlusal forces are properly directed along the long axis of the roots of the orthodontically uprighted tooth.
Most importantly, since mildly to moderately tipped molars can be properly prepared by the experienced clinician without orthodontic uprighting, this treatment modality is not routinely implemented. Although many clinicians consider orthodontic uprighting a time-consuming and expensive procedure, the author does not consider these factors to be the most significant limitations of this treatment modality. The presence of a third molar may necessitate its extraction prior to uprighting. This option is generally inappropriate for a healthy, fully erupted, third molar that is in proper occlusion. During treatment, it may be necessary for the clinician to reduce the vertical height of the crown for uprighting to proceed. When treating teeth with compromised crown height, this occlusal reduction may significantly decrease the future mechanical retention of the preparation.
Orthodontic uprighting is mandatory for severely tipped molars and/or molars that exhibit significant mesial bony defects. This procedure also corrects the improper direction of the occlusal forces along the long axis of the tooth in order to avoid further periodontal problems.2 Simply preparing a severely tipped tooth without uprighting and fabricating a two-piece FPD with a rigid attachment is not an adequate solution.
Orthodontic uprighting was traditionally advocated as the ideal treatment plan for tipped molars. In reality, however, it is mandatory only for the severely tipped molar or for a molar with significant mesial bony defects. Although orthodontic uprighting provides obvious clinical benefits, the experienced clinician can address the majority of mild to moderate tipping with proper preparation designs that do not require the use of orthodontics.
*Dean, University of Southern California, Ostrow School of Dentistry, Los Angeles, CA.
- Tulloch CJF. Adjunctive treatment for adults. In: Proffit WR, ed. Contemporary Orthodontics. 2nd ed. St. Louis, MO: Mosby, 1993:559.
- Pihlstrom BL, Anderson KA, Aeppli D, Schaffer EM. Association between signs of trauma from occlusion and periodontitis. J Periodontol 1986;57(1):1-6.