JADA Continuing Education
The Myth of Instant Orthodontics
An Ethical Quandary
Nancy Jacobson, DMD and
Charles A. Frank, DMD, MS
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ABSTRACT
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Background. There is a clinical trend of using porcelain veneer restorations (PVRs) for the correction of malaligned anterior teeth. Use of PVRs for this purpose raises clinical and ethical dilemmas.
Types of Studies Reviewed. A literature review of four different topics (PVR preparation, enamel thickness of anterior teeth, dentinal bonding adhesive effectiveness and PVR long-term success) was conducted to determine the optimal preparation for a successful PVR. The amount of tooth malalignment that may be corrected with a PVR without adversely affecting its success was calculated.
Results. The optimal preparation for a successful PVR may have dentin exposed in the body of the preparation. However, most of the preparation must be in enamel, and all the margins must end in enamel. The strength of a dentin bond varies greatly owing to a multistep, technique-sensitive cementation process and is weaker than an enamel bond. It is not possible to correct atypical gingival esthetics (uneven gingival margins, uneven papillae, short papillae and bulbous gingivae) resulting from malaligned teeth through use of PVRs.
Conclusions and Clinical Implications. Aligning a healthy tooth with a PVR is not a conservative procedure and more conservative treatment options (such as orthodontics, bleaching, direct bonding and enamelplasty) should be offered to the patient. In addition, the inability to restoratively improve gingival relationships with PVRs may result in achieving less-than-optimal esthetics. A clinician should present only treatment options that involve predictable, conservative restorations or that preserve healthy tooth structure. Aligning teeth with PVRs may create ethical dilemmas that can be resolved with the help of the American Dental Association Principles of Ethics and Code of Professional Conduct.
Key Words: Esthetics; enamel bonding; dentin bonding; porcelain veneers; orthodontics; ethicsAbbreviations: CEJ: Cementoenamel junction • IP: Interproximal papillae • PVR: Porcelain veneer restoration
The porcelain veneer restoration (PVR) has been an accepted restorative procedure for more than 20 years. Initially, clinicians thought that little, if any, tooth preparation was needed for a PVR. However, with time, clinicians determined that some tooth preparation was indicated.
In the early 1980s, PVRs were considered a conservative alternative to traditional full-coverage crowns or direct composite bonding. In comparison with full-coverage crowns, PVRs involve minimal removal of sound tooth structure while achieving optimal form, function and esthetics. Functionally sound crowns frequently are replaced after seven to 10 years of service owing to esthetic concerns.1 Numerous studies report that PVRs are more esthetically satisfying than are full crowns and have success rates that approach those of full-crown coverage.2–6 Also, direct composite bonding is more susceptible to discoloration7 and is more of a periodontal concern in that composite resin cannot be polished to the same surface smoothness as porcelain and, therefore, retains more food debris and plaque. Although tooth preparation is recommended for a PVR, placement of such a restoration still is considered by many clinicians to be a conservative procedure. Needed tooth preparation is minimally invasive, taking place primarily intraenamel. Direct composite bonding is more technically demanding and more time-consuming than is the PVR.8
When placed according to recommended tooth preparation and adhesive guidelines, a PVR is clinically acceptable, is long-lasting with relatively problem-free service and provides optimal esthetics.9 Traditionally, PVRs were placed to address esthetic issues such as unacceptable or peculiar tooth contour, interdental spacing, gingival recession, malformed teeth, worn teeth and tooth color.9 Minor tooth alignment issues (slight labiolingual discrepancies or rotation) may be corrected when primary indications call for PVRs.10 However, current trends advocate the correction of minor and even severe tooth alignment concerns involving healthy teeth. These restorative procedures are referred to as "instant orthodontics" or "two-appointment orthodontics."11,12 Crispin13 reported that the "full" veneer may be used to correct even mild-to-severe tooth alignment problems. These aggressive and unconventional approaches to resolving alignment problems are being justified by some clinicians by the reasoning that the patient does not want orthodontic treatment and elects to undergo restorative treatment.
Professional journals reflect the profession’s concerns regarding the current misuse or overuse of PVRs.1,9,11,12,14 With time, restorative and esthetic applications for PVRs have increased and will continue to evolve. Patients, inspired by culturally and commercially driven esthetic expectations, no longer limit their restorative demands to diseased teeth. In response to these demands, many clinicians are placing elective restorations in young patients and are preparing teeth more aggressively with less regard for preserving enamel. Until clinical and laboratory techniques are designed and refined to account for new restorative and esthetic demands, the success rate of PVRs surely will decrease.14 Authors voice a word of caution to those considering placement of a PVR to achieve esthetic goals, recommending that more conservative procedures be investigated.1,14
Although PVR preparation guidelines have been established, little information is available concerning the extent of tooth reduction needed to "correct" malaligned teeth. In this article, we attempt to determine the amount of tooth reduction necessary, the amount of enamel remaining in the preparation and the likely success of a PVR in correcting tooth alignment and achieving the patient’s esthetic goals.
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LONG-TERM SUCCESS RATES
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Long-term clinical success rates of PVRs reported in the professional literature approach those of full-coverage crowns. PVR failures are grouped into three categories: fracture, microleakage and debonding. Friedman14 stated that fracture accounts for 67 percent of PVR failures, microleakage results in 22 percent of failures and debonding is responsible for 11 percent of failures. Authors have reported that the primary factor in PVR failure, regardless of the type of failure, is exposure of an excessive amount of dentin in the preparation.4,15 The amount of enamel remaining after a tooth has been prepared for a PVR depends on the thickness of enamel, the preparation requirements of the PVR and the skill of the clinician. Additionally, the bond strength of the luting cement for a PVR increases as the amount of enamel remaining in the preparation increases.
Enamel thickness.
Generally, the thickness of enamel on a tooth’s crown increases from the cementoenamel junction (CEJ) to the incisal edge.16–20 Shillingburg and Grace16 measured the thickness of enamel on the labial and proximal surfaces of maxillary and mandibular anterior teeth at 2-, 5- and 8-millimeter levels above the CEJ on the labial surface. All anterior teeth except the maxillary lateral incisor have less than 0.5 mm of enamel in the cervical areas (2 mm incisal to the CEJ) on their labial surfaces.16 At the 5-mm level, the mesial and distal surfaces of all anterior teeth have more than 0.5 mm of enamel. The labial surfaces of the incisors at the 8-mm level have slightly more than 1 mm of enamel, whereas the labial surfaces of the canines have approximately 1.3 mm of enamel.
Study results indicate that as patients age, the thickness of the enamel on the facial surfaces of their anterior teeth decreases.16,17 The thickness of the enamel on the cervicofacial surface of the central incisor 1 mm above the CEJ ranges from 0.17 to 0.52 mm, with a mean thickness of 0.31 mm, and the enamel thickness on the midfacial surface (5 mm from the CEJ) ranges from 0.45 to 0.93 mm, with a mean thickness of 0.75 mm.17
Preparation requirements.
The optimal PVR preparation involves mostly the enamel, exposing little, if any, dentin. A minimally invasive enamel-only tooth preparation restored with a bonded PVR may be a conservative, strong, esthetically pleasing and predictable restoration. However, a PVR bonded primarily to dentin, as happens with aggressive enamel preparation, is weaker and less predictable.20 An appropriate restoration is one that conserves the most tooth structure while meeting the patient’s needs and desires.
The amount of tooth reduction for a PVR is determined by the biological limitations of the periodontium, the preparation requirements of the porcelain and the patient’s esthetic demands.21 The benefits of not preparing teeth for a PVR (avoiding the need for anesthesia or temporization5) are outweighed by the liabilities (the technical challenge of making a tapered edge that is not susceptible to fracture or the periodontal concern associated with plaque retention at an overcontoured margin5,21). In addition, esthetic and alignment concerns, when addressed restoratively, demand the removal of additional tooth structure.8 The type of ceramic used for the PVR determines the amount of tooth reduction necessary.22,23 Pressed ceramic veneers require more tooth reduction midfacially (0.5 mm to 1 mm) than do stackable porcelain veneers.23 Stackable porcelain veneers may be as thin as 0.3 mm midfacially.23 A PVR is stronger (less likely to fracture) when the preparation has only rounded line angles and no undercuts, and when the porcelain veneer is of a uniform thickness no less than 0.5 mm throughout.18,20–24
An appropriate restoration is one that conserves the most tooth structure while meeting the patient’s needs and desires.
The "standard" PVR preparation possesses the following elements. The reduction of labial and proximal surfaces must be uniform and no less than 0.5 mm.18,20–24 The preparation is extended interproximally to the lingual aspect of the papilla, paralleling the crown’s original form, to improve adhesion, hide the margin and increase the strength of the veneer.21,24 The reduction of the incisal edge depends on the need to increase the length of the crown and the labiolingual width of the incisal edge.21,24 PVRs with an incisal butt joint or feathered edge have fracture loads comparable with those of unprepared teeth.25 The incisal edge may be reduced as much as 2 mm with a butt joint.23,25 The preparation’s margins must be chamfered and must end in enamel.3,21,23,24,26 Interproximal and gingival margins of a PVR must end on enamel at the gingival margin or just within the gingival sulcus.21,24
Clinical capabilities.
Knowing the preparation parameters needed to make a successful PVR is extremely important; however, being able to meet those parameters clinically is equally important. Researchers have reported that clinicians are not uniformly able to reduce tooth structure for a PVR and that dentists frequently overreduce teeth.19,27–29 In a PVR preparation, dentin is exposed primarily in the cervical and proximal areas.19,30 The enamel usually is thin in these areas, making it easier to expose dentin unintentionally. Wat and colleagues31 reported that 95 to 100 percent of exposed dentin was found in the cervical one-third of the PVR preparation. Nattress and colleagues19 found the percent of dentin exposure in a PVR preparation to vary from 0 to 83 percent. Friedman14,23 claimed that a PVR has the greatest possibility of succeeding in the long term when more than 50 percent of the preparation is in enamel and all margins end in enamel. Concerns about exposing dentin and the long-term success of a PVR are evident from the development of various clinical techniques (dimple, depth groove and freehand) aimed at producing a uniform conservative preparation. Although none of these clinical techniques was able to provide uniform conservative tooth reduction, Cherukara and colleagues29,30 noted that use of the dimple technique was less likely than was use of the depth groove or freehand techniques to result in overpreparation of cervical and proximal areas.
The extent of a tooth’s crown flexure is directly related to the amount of enamel reduction.18 When a PVR restores the original thickness of enamel, no significant differences in crown flexure are found between natural and veneered teeth.18,32 A PVR mimics the physiomechanical characteristics (elastic modulus, fracture strength, hardness and thermal expansion) of enamel.18 Stresses accumulate at the junction between materials with different physiomechanical characteristics.33 Functional stresses transmitted to a luting cement are less when a porcelain veneer is bonded to enamel than when it is bonded to dentin.33 Addressing a patient’s desire for quick resolution of esthetic concerns such as tooth alignment by means of a PVR often requires the removal of enamel. Exposing more dentin within the preparation and ending margins in dentin increases the functional stresses placed on the luting cement, compromising the long-term success of a PVR.8,20,22
Bonding agent and luting cement.
The composite luting cement is the weak link in the chain of success for a PVR.15 Optimal bond strength is achieved when the thickness of the luting cement is minimal and uniform.15 Stresses from polymerization shrinkage (2.6 to 5.7 percent) and from differences between thermal expansion coefficients of tooth structure and luting cement adversely affect the strength of the bond.15,18 Of the two bonded interfaces (luting cement to PVR and luting cement to tooth structure), the one with the lowest adhesive forces (luting cement to tooth structure) is most likely to fail.15 Lafuente and colleagues34 reported that all four of the dual-cured resin cements they tested failed at the cement-tooth (dentin) interface.
The differences between minor, mild, moderate and severe levels of tooth malalignment are difficult to define and, therefore, are mostly subjective.
When luting cement is bonded to enamel, the bond generally fails at the cement-PVR interface, and the luting cement remains bonded to the enamel but debonds from the restoration. Microleakage occurs between the cement-restoration interface, protecting the underlying enamel. When luting cement is bonded to dentin, the bond fails at the dentin-cement interface. Microleakage occurs between the dentin and the cement, leaving the underlying dentin unprotected.34
As a result of the enamel thickness, the thickness of the PVR and the tendency of clinicians to overprepare, a PVR typically is bonded to enamel and dentin. The bond strength of the restoration is directly proportional to the remaining amount of bondable enamel.2 Study results indicate that the bond strength of resin cements to dentin is significantly lower than that to enamel.3,9,34–36 Bond strengths (to enamel, dentin or both) may increase as new generations of bonding agents are developed. However, authors shared this optimistic outlook in the early 1990s.5,21 At this time, the critical bond strength between dentin and luting cement necessary to prevent microleakage and debonding of a PVR is not known. In addition, dentin bonding is less predictable than enamel bonding and requires a demanding multistep cementation process. In vitro studies investigating dentin bonding of commercially available bonding agents and luting cements have not simplified the time-consuming, technique-sensitive cementation process of placing a PVR. The findings of these studies are inconsistent and contradictory in terms of providing insight to achieving an acceptable dentin bond in a clinical setting.
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PREPARATION REQUIREMENTS FOR RESTORATIVE ALIGNMENT OF TEETH
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Many authors acknowledge that minor alignment concerns—either functional or esthetic and involving crowding, facial-lingual arch displacement and spacing—may be resolved with a PVR.9,11,12 However, resolving alignment concerns with a PVR usually requires aggressive removal of tooth structure.8 The differences between minor, mild, moderate and severe levels of tooth malalignment are difficult to define and, therefore, are mostly subjective. The malaligned dentition usually is the result of multiple malaligned teeth and numerous types of malalignment.
We investigate in this article the effects of three types of tooth malalignment: rotation, labial and lingual tipping and interdental space. We include a discussion of preparation and esthetic issues affecting the correction of malaligned anterior teeth with a PVR.
Preparation requirements for rotated teeth.
The correction of a rotated incisor, positioned lingually to the arch, with a PVR may not require the removal of additional tooth structure (Figure 1A
). However, achieving optimal esthetics requires that the labial surface of the lingually rotated incisor must be overcontoured, creating many of the same challenges (functional, esthetic and periodontal) as those encountered with a no-preparation PVR. Overcontouring a PVR margin may be necessary to create a new emergence angle. Extensive reduction of the incisor’s incisal edge may be needed to establish a new contact point, and the contact area may be excessively wide and long, compromising the PVR’s success and esthetics.
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Figure 1. A. A lingually rotated maxillary right lateral incisor does not require aggressive reduction of its labial surface to be aligned restoratively. B and C. Labially rotated teeth necessitate additional reduction to be aligned restoratively. The red lines (X) represent the labial planes of aligned maxillary right lateral incisors. The blue lines (Y) represent the labial planes of rotated maxillary right lateral incisors. The intersection of the blue and red lines represents the center of rotation (CR). The angle X-CR-Y is the angle of tooth rotation. D. The degree of rotation that may be restored without exposing additional dentin is approximated by finding the tangent of the angle.
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Restoratively correcting a labially rotated anterior tooth with a PVR requires the removal of additional tooth structure (Figures 1B and 1C
). As the rotation radius of a crown increases, the degree of rotation possible without complete removal of the enamel decreases. An increase in the degree of tooth rotation is met with an increase in the removal of tooth structure (Figure 1D).
As shown in Figure 1B, the radius of rotation of the labially rotated maxillary right lateral incisor is the mesiodistal width of its crown (for this example, 7 mm). If the thickness of enamel on the labial surface of the lateral incisor is 1 mm, and 0.5 mm is removed for the PVR preparation, 0.5 mm of enamel remains. Less than 5 degrees of tooth rotation may be corrected without exposing dentin. When the radius of rotation is 3.5 mm, as shown in Figure 1C, slightly more than 8 degrees of tooth rotation may be corrected without exposing more dentin.
Because clinically determining the degree of tooth rotation is difficult, we offer an alternate means of clinically assessing which rotated anterior teeth may be aligned by using a PVR. When the thickness of enamel on the incisal one-third of the labial surface of an anterior tooth is more than 1 mm, the PVR is 0.5 mm thick and the labial surface of the rotated incisor is more than 0.5 mm labial to the labial surface of an adjacent tooth, additional dentin will be exposed in the PVR preparation.
Preparation requirements for labially and lingually tipped teeth.
The amount of incisal reduction needed for a PVR varies with the tooth’s inclination. Because the incisal edge of a lingually inclined tooth usually is superior to the incisal plane, more aggressive reduction of the tooth’s incisal edge usually is needed to correct tooth alignment and establish appropriate contacts with adjacent teeth (Figure 2). The middle and cervical thirds of the incisor’s labial surface require minimal removal of tooth structure. Because of esthetic concerns arising from a change in the emergence angle on the labial surface, the labio-cervical margin needs to be placed in the gingival sulcus. The incisal edge of a labially inclined tooth usually is apical to the incisal plane and requires less reduction. The entire labial surface of a labially tipped tooth must be reduced aggressively to be aligned with adjacent teeth (Figure 2).
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Figure 2. A. The labiolingual tipping of a central incisor around its center (C) of resistance. The labially inclined incisor is outlined in red and the lingually inclined incisor is outlined in black. The vertical difference between the colored arrows, marking the incisal edges of the respectively colored labially and lingually tipped incisors, reveals the amount of relative intrusion or extrusion. The incisal edge of a labially tipped incisor moves apically, whereas, as the incisal edge of a lingually tipped incisor moves incisally. B. The incisal edge of the labially positioned mandibular right central incisor is apical to the incisal edges of adjacent teeth. C. The incisal edge of the lingually positioned mandibular right lateral incisor is superior to the incisal edges of the adjacent teeth.
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Preparation requirements for interdental space.
Two types of interdental space may compromise esthetics: interproximal space and gingival gaps (also known as "open gingival embrasures" or "black triangles") (Figure 3, page 430). Teeth with an interproximal space have an open contact. Interproximal space may result from tooth-arch–size discrepancies in which the size of the anterior teeth is small in comparison with the size of the alveolar ridge, from an anterior-tooth–size discrepancy in which the maxillary anterior teeth are small in comparison with the mandibular anterior teeth or from adjacent teeth with divergent crowns. Interproximal space resulting from an anterior tooth size discrepancy is ideal for restorative closure. In these cases, interproximal space may be closed by establishing natural esthetic crown proportions restoratively (Figure 4). However, this process becomes more clinically challenging and less esthetically satisfactory as the interproximal space increases. The clinician creates a gradual emergence angle by placing the interproximal margin of the restoration in the gingival sulcus to reduce the possibility of creating an overhang or gingival gap. Closing interproximal spaces with PVRs frequently results in long contacts, making teeth look square and unnatural (Figure 5, page 431).
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Figure 3. A. An interproximal space (diastema) associated with an anterior tooth size discrepancy, where the mandibular incisors are proportionally larger than the maxillary incisors. As the mesial and distal surfaces of the central incisors are almost parallel, closing space restoratively will improve the crowns’ form and esthetic proportions. B. A gingival gap is apparent between the maxillary central incisors. Although the interproximal papillae are level, their lengths are not equal to one-half the length of the adjacent crowns, indicating gingival recession. The maxillary central incisor crowns are triangular in shape, resulting in a contact point that is positioned incisally.
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Figure 4. A. The maxillary anterior interproximal spaces are a result primarily of an anterior tooth size discrepancy. The interproximal surfaces of the maxillary incisor crowns are almost parallel. B. Natural-looking maxillary incisor crowns were restored with resin-based composite. The patient refused orthodontic treatment. This reversible procedure does not correct the incisal cant or open bite, but it does allow the patient to opt for orthodontics in the future.
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Figure 5. A. The space mesial and distal to the maxillary central incisors was closed with resin-based composite restorations. The patient initially refused orthodontic treatment. The space between the central incisors was excessive. The restored central incisors appear unnatural and the restorations created interproximal ledges. B. After removing the restorations, the clinician closed the mandibular interproximal spaces orthodontically. Optimal overjet and overbite were established and the anterior interproximal spaces were repositioned orthodontically to facilitate restorative space closure. C. Natural crown form was achieved with resin-based composite restorations without interproximal ledges.
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Gingival gaps result from recession of the interproximal papillae (IP), from triangular crowns with contacts incisal to healthy IP or from adjacent teeth with divergent roots.37–39 It is difficult to eliminate via restoration a gingival gap resulting from gingival recession. The abrupt change needed in the emergence angle requires that the restoration’s margin be placed in the gingival sulcus. When this is done in the presence of gingival recession, the margin undoubtedly will end in dentin. Gingival gaps associated with triangular crowns and healthy IP may be closed restoratively. Although the cervical margin on the proximal surface is placed in the gingival sulcus, a normal contact and crown form may be created. Gingival gaps resulting from adjacent teeth with divergent roots have IP that are wide and flat, making it difficult to close space restoratively. The margin on the tooth’s proximal surface is placed in the gingival sulcus and the contact is lengthened apically, creating a square, unnatural-looking crown.
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GINGIVAL CONCERNS REGARDING RESTORATIVE ALIGNMENT OF TEETH
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In normal gingival relationships for the maxillary anterior teeth, the IP are about one-half as long as the crowns, the IP are level and the relationship of the gingival margins is opposite to the relationship of their incisal edges37 (Figure 6, page 431). Generally, gingival relationships for the mandibular anterior teeth become a concern only for the aging patient, as the smile line drops and the IP recede, exposing gingival gaps. Esthetics is compromised when the IP are not normal in length, the IP are not level or the gingival margin relationship is unnatural. Malaligned anterior teeth often are associated with atypical gingival relationships. These atypical relationships are esthetically compromising. Atypical gingival relationships cannot be improved with a PVR.
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Figure 6. The interproximal papillae are almost level and about one-half the length of the adjacent crowns. The gingival margin of the lateral incisor is incisal to the gingival margins of the adjacent teeth. The incisal edge of the lateral incisor is apical to the incisal edge/cusp tip of the adjacent teeth.
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Soft-tissue changes associated with rotated teeth.
The CEJ on the proximal surfaces of an anterior tooth is incisal to the CEJ on the labial or lingual surfaces. With increased rotation, the interproximal surface of a labially rotated incisor widens the IP, whereas the palatally rotated interproximal surface shortens the IP (Figure 7). Establishing a new contact on a lingually positioned interproximal surface may create an unesthetic long contact. Not only does a PVR preparation of a labially rotated tooth require removal of additional tooth structure, but also the margin of the PVR on the labially rotated proximal surface may not end in enamel.
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Figure 7. The papilla on the distal aspect of the mesially rotated maxillary right lateral incisor is widened, whereas the papilla on the distal aspect of the maxillary left lateral incisor is normal. Note the shortened papilla on the mesial aspect of the rotated maxillary right lateral incisor compared with the normal length of the papilla on the mesial aspect of the maxillary left lateral incisor.
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Soft-tissue changes associated with labially and lingually tipped teeth.
The gingival margin on the labial surface of a lingually inclined tooth is incisal to the gingival margins of adjacent teeth, the IP are shorter and the labial gingiva may be thicker (more bulbous) than those of a normally inclined tooth (Figure 8, page 432). Restoratively correcting the position of a lingually inclined tooth creates a short, square crown. The gingival margin of a labially tipped incisor moves apically, the IP are longer and the labial gingiva may be thinner. Restoratively correcting the position of a labially inclined tooth may create a long, narrow crown.
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Figure 8. A. The blue arrows demonstrate the vertical differences between the cementoenamel junctions (CEJs) of labially and lingually tipped teeth around the center (C) of resistance. The tooth’s CEJ moves apically when tipped labially and incisally when tipped lingually. The green arrows indicate the most incisal position of the CEJ interproximally. The distance between the blue and green arrows of the labially tipped tooth is greater than the distance between the blue and green arrows of the lingually tipped tooth. This demonstrates that the length of an interproximal papilla increases when a tooth is labially tipped and decreases when lingually tipped. B. The yellow arrows point to the CEJ on the labial surface of teeth tipped labially and lingually. The horizontal difference between the arrows increases when a tooth is tipped labially and decreases when tipped lingually. This indicates that a tooth moves labially within the alveolar ridge when labially tipped and lingually when lingually tipped. C. Note the more incisal gingival height of the lingually inclined mandibular right lateral incisor compared with the gingival height of the contralateral tooth. The lingually inclined mandibular right lateral incisor has an interproximal papilla shorter than that of the contralateral tooth. D. The lingually inclined mandibular right lateral incisor has a thicker gingival cuff than does the contralateral tooth.
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Soft-tissue changes associated with inter-dental space.
Wider embrasure areas have shorter and flatter IP, whereas narrower embrasure areas have longer and more pointed IP.38 Tarnow and colleagues39 reported that an embrasure area always is filled by the IP when tooth contact is no more than 5 mm above the alveolar ridge. Gingival gaps and interproximal spaces associated with IP that are 5 mm long and level with adjacent IP are ideal for restorative space closure. IP less than 5 mm long may result from gingival recession or wide embrasure spaces. Restoratively closing space with a short IP creates long contacts with square, unnatural-looking crowns.
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ETHICAL CONCERNS REGARDING RESTORATIVE ALIGNMENT OF TEETH
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The use of PVRs to correct malalignment presents significant clinical as well as ethical quandaries. The American Dental Association Principles of Ethics and Code of Professional Conduct provides principles that can be used to guide a clinician in evaluating the ethical dilemmas raised when treating malaligned teeth restoratively.40
Nonmaleficence.
The credo "do no harm" is even more critical when treating healthy teeth for esthetic reasons, because the treatment offers no direct health benefit. In the absence of any health benefit, it is important to present the most conservative treatment option that meets the patient’s esthetic goals.
Veracity and informed consent.
Veracity requires that we tell the truth but also that we do what we say and say what we do. If we describe treatment to the patient as being conservative or minimally invasive, we should perform treatment that is indeed conservative. Aggressive preparation of malaligned teeth for PVRs is not minimally invasive or conservative treatment.
Informed consent requires that full disclosure of positive and negative aspects of treatment is made to the patient and that the patient understands his or her options. In addition, if a patient refuses to accept part of a comprehensive treatment plan, the clinician must discuss with him or her the biological and functional consequences of this choice, as well as the esthetic limitations of partial treatment. The patient who refuses orthodontic therapy because of perceived cost or length of treatment should be informed of the possible risks involved in aggressive preparation of teeth and the subsequent need to replace restorations with time. It is important to remember that clinicians can only try to be objective when presenting treatment options. They have their own biases about treatment options that can be communicated to the patient by the manner in which they present those options.
Patient autonomy.
Patients who seek esthetic dental treatment often have a vision of or goal for their care that is based on information acquired from the mass media. Although patients’ esthetic goals are important in the treatment planning process, a dentist has an ethical responsibility to educate them concerning realistic goals and appropriate treatment options. Patient autonomy, by itself, is not a rationale for treatment. If a patient made a request for extraction of a healthy tooth for his or her own esthetic goal, would that be reason enough to carry out the procedure? Patient autonomy allows the patient the right to refuse or select treatment from a number of appropriate options. Patient autonomy does not give the patient the right to choose inappropriate treatment. Inappropriate treatment is not justified because it is what the patient believes he or she wants.
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CONCLUSION
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The clinician should prepare teeth as minimally as possible to deliver the most predictable and conservative restoration. Preparation of a tooth for a PVR is not a reversible procedure, and it begins a restorative continuum resulting in the removal of additional tooth structure. Restorative alignment of a malaligned healthy tooth with a PVR is not a minimally invasive procedure and should not be presented as such to the patient. More conservative treatment options should be considered, especially in younger patients with unrestored, healthy teeth. Even when a tooth needs to be restored, orthodontic alignment of a tooth before its restoration reduces the removal of healthy tooth structure, decreases the amount of dentin exposed and minimizes the possibility of creating pulpal or periodontal problems.
Clinicians offer two objections to orthodontic repositioning of teeth to justify restorative alignment of teeth with a PVR: the cost of orthodontic treatment and its length. Less aggressive procedures such as bleaching, recontouring teeth and placing direct-bonded restorations in conjunction with orthodontic tooth alignment are more cost-effective (in terms of time and money) than a PVR with time. The cost of orthodontic treatment is more than compensated for by the reduction in the number of teeth that need to be restored and in the number of times a tooth must be restored throughout a patient’s lifetime, as well as by the reduction in pulpal and periodontal complications of treatment. Minor alignment discrepancies take a few months to correct orthodontically, whereas many moderate-to-severe alignment concerns may be resolved in six to 12 months. Frequently, minor alignment concerns may be treated by means of a removable appliance. When a fixed orthodontic appliance is indicated, the ceramic bracket is an esthetic alternative.
The ethical implications of PVRs for correction of tooth malalignment should not be ignored. Patient autonomy is important, but it does not outweigh all the other principles in the profession’s code of ethics.
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FOOTNOTES
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Dr. Jacobson is a clinical assistant professor, Jacksonville Clinic, College of Dentistry, University of Florida, 2028 Boulevard, Jacksonville, Fla. 32206, e-mail "njacobson{at}dental.ufl.edu". Address reprint requests to Dr. Jacobson.
Dr. Frank is an affiliated clinical assistant professor, Jacksonville Clinic, College of Dentistry, University of Florida, Jacksonville.
Disclosure: Drs. Jacobson and Frank did not report any disclosures.
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ABSTRACT
LONG-TERM SUCCESS RATES
