Department of General Dentistry: Faculty Research and Presentation
A multidisciplinary approach to the management of a maxillary midline diastema: A clinical reportAnterior maxillary spacing has been shown to be one of the most negative influences on self-perceived dental appearance, and a maxillary midline diastema (MMD) is commonly cited by patients as a primary concern during dental consultations. MMD has been defined as a space greater than 0.5 mm between the mesial surfaces of the 2 maxillary central incisors. An MMD greater than 2 mm in the mixed dentition is unlikely to spontaneously close. African Americans are more than twice as likely to have an MMD than whites or Hispanics. In esthetic situations, without a comprehensive smile analysis and proper planning, overtreatment and undesirable effects can occur. Tooth size especially has been emphasized as the primary element of an esthetic smile design. One method of establishing tooth size is tooth biometry as described by Chu. He reported that maxillary anterior tooth widths average 8.5 mm for central incisors, 6.5 mm for lateral incisors, and 7.5 mm for canines and that 80% of the patient population falls within ±0.5 mm of these values. Other important elements of smile analysis include the dental midline, tooth morphology, axial inclinations, and the soft tissue components of gingival health, levels, and harmony. The direct bonding technique is a straightforward, conservative method for diastema closure. However, artistic skills, a knowledge of tooth morphology, and the appropriate selection and use of composite resin materials are essential for success. According to Spear and Kokich, “some existing dentitions simply cannot be restored to a more pleasing appearance without the assistance of several different dental disciplines.” Therefore, complex esthetic dilemmas may require more than one dental discipline, for example, operative dentistry and orthodontics, to establish a functional, maintainable, and pleasant smile. This article illustrates a clinical situation in which an MMD was addressed by first completing a comprehensive smile analysis, followed by closure using limited orthodontics and direct composite resin restorations.
Aesthetic improvement of a smile using minimal intervention procedures. A case reportTooth discoloration, particularly affecting the maxillary anterior teeth, is often an esthetic concern for dental patients.1 The most common cause of intrinsic tooth discoloration is dental fluorosis (DF),1 which is enamel hypomineralization due to long-term ingestion of high levels of fluoride during tooth mineralization.2 DF results in white opaque areas or discolorations ranging from yellow to dark brown, with porosities on the enamel surface.3 A widely-used scale for classifying the severity of DF is the Tooth Surface Index of Fluorosis (TSIF), developed by Horowitz, by which the examiner determines the extent of affected enamel by estimating the amount of DF as a fraction of the total visible enamel surface.4 Microabrasion, introduced by Croll and Cavanaugh in 1986,5 is a technique used to correct surface enamel irregularities and remove intrinsic enamel stains through the application of hydrochloric acid combined with pumice in a paste.6 When performed correctly and conservatively, the amount of enamel loss from microabrasion is clincally insignificant.7 The success of microabrasion depends upon the extent and severity of the discoloration, and occasionally a slightly yellowish appearance will result from the yellow dentin shade showing through the translucent enamel.8 The final appearance can be improved by dental bleaching, with long-lasting results.7 The following article is a clinical report of the use of microabrasion combined with nightguard bleaching with 10% carbamide peroxide to improve the appearance of teeth affected by fluorosis.
In Vivo Pilot Study: Effect of Dehydration/Rehydration on Upper Anterior Tooth Color ChangeIsolation of tooth structure during fabrication of a bonded, direct, resin-based restoration is essential to optimizing its potential for long-term clinical success. Failure to protect etched enamel and bonding agents from contamination by saliva results in inadequate and unpredictable interfacial bonding of the restorative composite, potentially leading to marginal discoloration, open margins, recurrent decay, or ultimately to restoration loss or failure. A consequence of tooth isolation during placement of direct, esthetic restorative resins is the dehydration of enamel surfaces that will not be coated with saliva, and will, over time, lose water that has penetrated into the outer enamel layers (will dehydrate). The longer the tooth isolation time, the greater will be the subsequent loss of water from enamel. Presence of this water in enamel helps to provide for a stable tooth color. In teeth, the observed tooth color is the result of internal light penetration and interaction with tissues below the surface. Enamel is a translucent material, passing a great majority of transmitted light to fall on the more opaque and yellow-colored tissue underneath of it: dentin. In the hydrated state, enamel is more translucent than in its dehydrated state. The white opaque appearance of dehydrated enamel can be of great clinical concern, once a rubber dam has been removed, and the treated teeth with newly placed restorations are observed. Usually, because of the opaque, white nature of recently dehydrated enamel, there is an initial mismatch between an esthetic restoration just placed and its surrounding, remaining enamel. Patients are normally forwarded of this consequence, and are advised that a period of time needs to pass before the surrounding enamel becomes rehydrated, and more translucent (less opaque), before its pre-isolated color returns to a natural state. It is hoped that, at that time, the new restoration will perfectly match the color characteristics of the remaining enamel, and the recent replacement will not be visible at all, but will instead optically blend in without notice. However, prior to that time, there are definitely distinct color differences between a recently placed resin restoration and its surrounding tooth structure. To date, little-to-no information is available on the rate at which a clinician or patient can expect isolated enamel to return to its pre-isolated color, and when to expect this esthetic blending to occur.