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2555;35:131-40CU Dent J. 2012;35:131-40
The use of a removable orthodonticappliance for space management combinedwith anterior esthetic restorations:a case reportPasumon Sawangnimitkul DDS1
Chalermpol Leevailoj DDS, MSD, ABOD, FRCDT2
1Graduate Student, Esthetic Restorative and Implant Dentistry Program, Faculty of Dentistry,Chulalongkorn University2Esthetic Restorative and Implant Dentistry Program, Faculty of Dentistry, Chulalongkorn University
AbstractSpacing in the esthetic area results in an unconfident smile. To solve this problem, many
alternative treatments can be used with multidisciplinary knowledge: for example, orthodontictreatment and restorative treatment. The treatment plan should be performed under conservativeconsideration, while the esthetic outcome should persist in the long term. Instead of using onlyrestorative treatment to close several spaces, minor tooth movement before restorative procedures mayachieve a preferable result since the teeth can be realigned to the proper position; it also requires lesstooth structure preparation. This case report demonstrated the use of a removable orthodontic applianceto distribute the anterior space before restoring the bilateral peg-shaped lateral incisors with porcelainlaminate veneers to close all the spaces in the maxillary anterior area. This resulted in a naturalappearance with healthy gingival tissue during the 8-month follow-up period. This treatmentprinciple can be applied for use in other small spacing cases.
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Key words: esthetic; interdisciplinary approach; peg-shaped lateral incisor; porcelain veneer;removable appliance; spacing
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IntroductionToday, most people are concerned about their
health and appearance; this includes healthy teeth anda beautiful smile, which will increase their confidencewhen out in public. The so-called esthetic zone in theanterior maxilla has the greatest impact on smiledesign. Tooth anomalies occurring in this area-such asmisalignment, discoloration, or malformed and missingteeth-can lead to unattractive smiles with non-harmo-nious pink and white esthetic in the esthetic zone, whichmay sometimes reduce a persons confidence insmiling during their social lives.1
One common esthetic problem in the maxillaryanterior area is a peg-shaped or mesiodistally deficientmaxillary lateral incisor. The definition of a peg-shapedlateral incisor is given in the Glossary of ProsthodonticTerms (2005) as an undersized, tapered tooth.2Atypical tooth shape may result from an inappropriateproliferation of the tooth bud cells during toothformation.3 Peg-shaped lateral incisors may causespacing in the anterior maxilla, transposition ofadjacent teeth, and prolonged retention of deciduouscanines.4 The incidence of peg-shaped lateral incisorsis approximately 2% to 5% of the population, andoccurs more frequently in females than in males.5,6Anatomically, peg-shaped lateral incisors are foundpredominately on the left side of the arch.5,7
There are two alternative treatments for peg-shapedlateral incisors. The first option is to move the canineforward with a fixed orthodontic appliance to close thespace between the lateral incisor and canine, and thenreshape the lateral incisor to make it appear morenormal. The other treatment is to maintain the caninesin Angles class I relationship and restore themalformed teeth with resin composites, porcelainveneers or crowns. These restorations are used to closethe space and change the peg-shaped lateral incisorsinto their natural shape.8 The treatment time of thelatter method is less, and the esthetic and functional
outcomes are satisfactorily achieved.4,9 However, insome cases the clinical situation is somewhat morecomplex and may not be able to be corrected by onlyrestorative means. When teeth are severely misaligned,an orthodontic appliance can contribute to creating theproper tooth position prior to any restorative treatment.Furthermore, in some cases, periodontal surgery maybe indicated in order to improve the gingival levels tocreate a more desirable symmetry and harmony of thepink esthetic.
Removable orthodontic appliances could beconsidered as an alternative treatment for patients witha single or a few misaligned teeth. Patients feel morecomfortable with removable appliances compared tofixed appliances since they can be removed occasionally.A removable appliance will not compromise the patientsoral hygiene, and it requires less clinical chair timesince the appliance is fabricated in a laboratory.10 Itcan only apply tipping force to move the misalignedtooth; therefore, the treatment needs strict supervisionby the dentist. Moreover, accomplishment of thetreatment depends on the patients cooperation. It isalso difficult to create complex tooth movementbecause the removable appliance cannot achievetwo-point contacts on teeth, which are necessary tocontrol tooth movement in three dimensions.10,11 Inaddition, the acrylic plate may affect speech and causediscomfort while wearing the appliance.10
A removable appliance with clasps and fingersprings may be used for minor tooth movement in theanterior area, such as a small median diastemaapproximately 2 millimeters or less. Palatal finger springsare often used to move teeth in a mesiodistal directionin orthodontic treatment.11 Optimum force forcontinuous tooth movement in a single-root anteriortooth is approximately 25-40 grams.10,12 Activation ofthe palatal finger springs at 1.5 to 2 millimetersdistance can move the maxillary central incisor about 1millimeter in one month. Excessive force can complicate
the treatment, and insufficient force can prolong thetreatment time.10 Although removable appliances witha finger spring can shift the tooth to the correct position,the tooth does not have bodily movement in the sameway as with a fixed appliance because the finger springhas only a point contact on the tooth. Therefore, onlythe tipping movement can be performed by removableappliances.10
Peg-shaped lateral incisors need restoration, suchas direct resin composite or porcelain laminate veneers,to restore the tooth shape and close the space.13,14While composite veneers have the advantage of beinga low-cost conservative procedure, porcelain laminateveneers have other advantages such as high longevity,material biocompatibility, and a highly estheticresult.14,15 Porcelain can mimic the natural appearanceof enamel.16 Moreover, porcelain veneers retain lessstaining and are more durable compared to resincomposite.15 Friedman and colleague reported that thelong-term clinical longevity of porcelain veneers wasup to 15 years, with only 7% failure rate due tofracture, leakage, or veneer debonding. This indicatesthat porcelain veneers are very predictable restorations.17However, in order to fabricate a high-quality porcelainveneer, teeth need to be prepared to allow for adequatethickness of the material. Generally a feldspathicveneer requires a minimum thickness of 0.3 millimeters.16However, the fabrication of a 0.3-millimeter-thickhigh-strength leucite-reinforced veneer is very difficult.One study revealed some cracking of 0.3-millimeter-thickveneers during cement polymerization when the veneerswrapped over the incisal edge.18 From these data, therecommended thickness for the veneers should be atleast 0.5 millimeter if they cover the incisal edge orinterproximal area.18 However, peg-shaped lateralincisors need minor preparation because the teeth haveenough space for porcelain veneer fabrication except atthe cervical margin. Sufficient tooth preparation at thecervical margin is recommended in order to avoid anovercontoured restoration.18
In this case report, the patient was treated byminor tooth movement with a removable appliance todistribute the spacing more favorably. Then estheticrestorations were performed by correcting the peg-shaped lateral incisors with ceramic veneers.
A 19-year-old male patient was referred to theEsthetic Restorative and Implant Dentistry Clinic,Chulalongkorn University, for closing the space in theupper anterior maxillary region and to change bothlateral incisors shape. Intraoral examination revealedspacing between teeth 11 and 21 due to the distalmigration of tooth 21 approximately 0.5 millimeter,while the mesial of tooth 11 coincided with the dentaland facial midline. The shifting of tooth 21 waslikely caused by malformation of the lateral incisors.The patient presented with two peg-shaped lateralincisors, teeth 12 and 22 (Fig. 1A). Tooth 13 wasslightly mesiolingually rotated. All of the teeth weresound and asymptomatic. The patient had 2 millimetersof overjet and 2 millimeters of overbite. Radiographicexamination found that tooth 21 was minorly tippedto the distal. Teeth 13 to 23 had an intact laminadura, with no periapical radiolucency observed(Fig. 1B-D).
Our treatment plan was to do minor tooth movementof tooth 21 to close the median diastema (withoutmoving tooth 11) by using a removable orthodonticappliance, and then to restore both peg-shaped lateralincisors with ceramic veneer facings. The orthodonticremovable appliance was composed of one finger springat distal of tooth 21, which generated force to movetooth 21 mesially, and one acrylic stop at distal oftooth 11, which helped stabilize the tooth 11 whentooth 21 was moved into contact. This procedure neededtwo weeks of force application and two weeks ofstabilizing the tooth in position before the finalrestorations were performed. The case was finished by
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placing ceramic veneers on the two lateral incisors toclose the space and change the tooth shape. The patientwas asked to wear a full-time retainer for three m