shortened dental archA phased restorative treatment strategy can provide the opportunity for many of our patients to proceed with a plan requiring a significant financial commitment.  Many times patients present with first and second molars – which are automatically included in the overall treatment plan because, we are oriented to save teeth.

What happens when a decision is made to focus on 10 upper teeth and 10 lower teeth where the contacts created by the second premolar become the terminal opposing tooth contact?

The Shortened Dental Arch


This patient presents with a fixed bridge extending from the lower right canine to the lower right second molar where the second premolar and first molar are missing. (Fig. 1) The lower right second molar has endured root canal treatment and presents with a radiographically evident root fracture.  The patient explained that dental implants were not previously presented as an option for treatment in either the lower right or the upper left.  Notes taken from her health history include Type I Diabetes, Hypothyroidism and history of smoking – all factors potentially limiting to the overall healing response. (Figs. 2 & 3)

shortened dental archRemoving the lower right second molar and sectioning the fixed bridge is an option for this patient.  One option that could be considered would be to maintain the second premolar pontic for a shortened dental arch that includes opposing contact of 10 pairs of teeth, specifically the incisors and premolars.  Distally cantilevered pontics are generally considered to put the anterior abutment teeth at risk.  Other options include a dental implant supported restoration in the second premolar area, as well as, a removable partial denture with a unilateral distal extension (Kennedy Class II).

A review article by Armellini and von Fraunhofer presents a rationale for the minimal requirements of a functional collection of natural teeth as defined by the World Health Organization to include 20 teeth.  The conclusion emphasizes the importance of the patient’s ability to adapt to the altered condition with the recommendation that the treatment for a shortened dental arch be modified based on each individual patient.

The restorative treatment plan that appeals to this patient includes a dental implant supported restoration in the lower right second premolar position.  This will allow for the opportunity to evaluate the healing response specifically related to the process of osseointegration.  The patient can then move forward with more information in terms of the restoration of the lower first molar areas – no further treatment, dental implant supported restorations and to be complete – a removable partial denture.

Are there any concerns that come to mind?

How about decreased surface area available to spread out the functional chewing load in an every day diet.  In an article by De Oliveira, a finite element analysis study demonstrated greater displacement of the teeth in a shortened dental arch when compared with a full compliment of natural teeth.  What was interesting was that the displacement recorded was greater in the mandibular teeth relative to the maxillary teeth.

What happens to the dental implant supported restoration in the lower right second premolar?  How would this change your plan?

References:


  1. The shortened dental arch: A review of the literature.  Armellini, D & von Fraunhofer, JA.  Journal of Prosthetic Dentistry 92:531-535;2004.

  2. Tooth displacement in shortened dental arches: A three-dimensional finite element study.  De Oliveira, et. al.  Journal of Prosthetic Dentistry 111(6):460-465;2014.

Douglas G. Benting, DDS, MS, FACP, Spear Visiting Faculty and Contributing Author. [ www.drbenting.com ]

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