DENTAL HARD TISSUE DESTRUCTION 119 



mental factors may be different in the two diseases, the teeth them- 

 selves may be protected in both by decreasing the solubility of the 

 tcoth substance, irrespective of the type of dissolving agents. 



Because erosion has a tendency to recur even after restoration 

 of the gross defect, one mav by the same token suggest that the 

 tooth substance along the filling margins be similarlv fortified by 

 topical application of fluoride at regular intervals. With respect to 

 the nature of restoration, certain silicates may have the advantage 

 of their own fluoride contamination, which has been thought to be 

 a factor in limiting recurrence of secondary caries along the filling 

 margin. This possible advantage is, however, offset by other chem- 

 ical and physical inadequacies, noticeably in the class V type of 

 restoration often called for in the management of advanced wedge- 

 shaped cervical erosion. 



The observation was made above that the erosion lesion, despite 

 its seemingly "clean" look to the naked eye, may be the site of a 

 microscopic bacteria-laden mucous plaque, potentially involved as a 

 destructive factor. This plaque, as well as other environmental con- 

 tacts with lip, cheek, tongue, mucous glands, etc., would presum- 

 ably prevail even after the eroded defect has been restored by a 

 filling or inlay. This being so, it may conceivably be of advantage 

 to so mold the restoration that the above chemical and physical 

 influences are concentrated against the bulk of the restoration 

 rather than the margins of the tooth substance. 



This reasoning might lend support to a practical modification of 

 cervical restorations brought to my attention through a personal 

 communication by Dean Maynard Hine of Indiana University ( orig- 

 inal publication, if any, is not known). According to this procedure, 

 the class V inlays for restoration of cervical erosion should be pro- 

 vided with a slight central concavity rather than convexity. In other 

 words, instead of making the usual cervical contour (appropriate as 

 this would be for protection of the gingival margin), the rationale 

 v/ould be to invite environmental agents to settle into some shallow 

 depression in the center of the surface of the restoration. It is pos- 

 sible that this artificial duphcation of a filling profile, which to a 

 slight degree mimics the profile or contour of the early erosion 



