Implant over-dentures are considered to be a very good treatment option for edentulous mandibular alveolar ridge. Are there any risks or changes involved in the edentulous maxilla in persons wearing mandibular implant-retained overdentures ?
Dear Dr Haroon,
I invite you to read
Abstract
STATEMENT OF PROBLEM:
It has been suggested that risk for severe resorption in the anterior maxilla is increased in persons wearing mandibular implant-retained overdentures. However, little information is available about the changes in the edentulous maxilla after mandibular implant treatment.
PURPOSE:
This study determined the possible changes in the width of the maxillary residual ridge 6 years after receiving mandibular implant-supported or implant-mucosa-supported overdentures and evaluated the association between the anatomic changes and subjective complaints with maxillary complete dentures.
METHODS AND MATERIAL:
The subjects for this study (n = 55), enrolled among the participants of a prospective clinical trial, were randomly assigned into 3 groups treated with: (a) implant-supported overdentures on a transmandibular implant system (n = 21); (b) implant-mucosa-supported overdentures on 2 IMZ implants (n = 20); or (c) conventional complete dentures (n = 14). A lingual contact occlusion concept with anterior open bite was used for tooth arrangement in all subjects. Diagnostic casts were made at baseline, and again at the 6-year follow-up. Most prominent points perpendicular to the crest of residual ridge were located in the incisor, canine, and premolar regions, after which the width of the ridge was recorded at these points with a Boley gage. Subjects' opinions on their dentures were evaluated with a questionnaire.
RESULTS:
Significant reduction in the width of the ridge was found in all measurement areas (mean difference = 0.4 to 0.6 mm; P
The question relates to the effect of a mandibular over denture on the resorptive pattern in the edentulous maxilla.
It arises because we think about the "Combination Syndrome" described by Kelly and later discussed by Desjardins and Saunders. with combination syndrome the thought is that posterior settling of a mandibular kennedy class 1 removable partial denture will create excessive force on the anterior maxilla from the mandibular incisors and this will be associated with fibrous hyperplasia of the anterior maxilla, down growth of the tuberosities,, posterior mandibular residual ridge resorption, flaring of the mandibular teeth with associated bone loss and papillary hyperplasia.
The concern with an implant retained mandibular over denture if two implants are used in the lateral incisor to canine area is that posterior ridge resorption will concentrate forces in the anterior maxilla and this will cause a similar syndrome as the one Kelly described. Probably not an issue with more than two implants because three or more will define a plane and that will essentially reduce/eliminate the posterior settling. We know that studies on mandibular fixed prostheses (full arch retained by implants) does not cause combination syndrome.
The references that Dr. Reyes cites is describing change in ridge width and fails to establish a clinically meaningful issue. Will long term negative effects be observed if the 2 implant over denture remains in place without periodic re-adaptation to underlying tissue in the posterior mandible? I am not aware of any compelling research suggesting this problem. Of course the prudent thing to do is to be diligent regarding tissue surface re-adaptation as changes occur and confirming (and adjusting as needed) adequacy of occlusion over time.
Dear Colleagues, thank you for the valuable input .... actually I was going thru this and found it very interesting also.
Significant reduction in the width of the ridge was found in all measurement areas (mean difference = 0.4 to 0.6 mm; P
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