Literature review

Potentiating Orthodontics

Nidhi Rathore,1 Shivendra Pal Singh,2 Dharma R.M,3 Asavari Desai4

1-Senior lecturer, Department of Orthodontics and Dentofacial Orthopaedics, 2-Department of Periodontics and Oral Implantology, Eklavya Dental College & Hospital, Rajasthan University of Health Sciences, Kotputli, Rajasthan. India, 3-Professor, Department of Orthodontics and Dentofacial Orthopaedics, DAPM RV Dental College & Hospital, Rajiv Gandhi University of Health Sciences, Bangalore, Karnataka. India, 4-Senior Lecturer, Department of Orthodontics and Dentofacial Orthopaedics, Manipal College of Dental Sciences Manipal University, Mangalore, Karnataka, India.

Abstract

Major reason for taking orthodontic treatment is enhancement of esthetics. While most of the corrections of malocclusions can be handled with orthodontic treatment, certain conditions require multidisciplinary approach to provide a more favorable result. Various conditions that require integration of orthodontic therapy with restorative and periodontal procedures include attrited incisal edges, missing lateral incisors, microdontia, dental fluorosis, gingival recession, gingival hypertrophy, gummy smile, high frenal attachment, pigmented gingiva etc. The aim of this article is to review those conditions that require adjunctive procedures along with comprehensive orthodontic treatment to achieve the best possible esthetic result.

Keywords

Esthetics; multidisciplinary approach; orthodontic treatment.

*Author for correspondence:

Nidhi Rathore, Senior lecturer, Department of Orthodontics and Dentofacial Orthopaedics, Eklavya Dental College & Hospital, Rajasthan University of Health Sciences, Kotputli, Rajasthan. India. Email: nidhirathore11@gmail.com

Introduction

Clinical orthodontics is a service that should be grounded in science and biology. The science of decision in orthodontic treatment planning implies identification of alternative as well as additional procedures to achieve the best possible result for the patient. Cosmetic enhancement has become a crucial part of orthodontic therapy as patients evaluate the treatment outcome by their enhanced facial appearance and improved smiles. Esthetic dental contouring is commonly used to alter the length, shape or position of your teeth and when used in conjunction with orthodontic treatment it is helpful in cases with minor imperfections such as minor chipping of teeth, worn edges etc. Other factors affecting the final outcome of orthodontic therapy are gingival shape, curvature and color for the correction of which periodontal surgical procedures can be performed. Prosthodontic rehabilitation is required in yet another series of cases having missing teeth and microdontia. The aim of this article is to review various conditions that require adjunctive procedures along with comprehensive orthodontic treatment to achieve best possible esthetic outcome.

 

Following conditions require a multidisciplinary approach for enhancing orthodontic treatment outcome

Periodontal procedures enhancing orthodontic treatment outcome

Periodontal procedure like gingival depigmentation is required in cases where there is an unaesthetic dark (black) gingival display especially in people with fair skin and high lip lines, however it is avoidable in patients with dark skin color which matches their gingival shade and this procedure is recommended only after periodontal health is restored. The gingiva is the most frequently pigmented areas in the oral cavity in melanin hyperpigmentation. A direct relationship between the degree of pigmentation seen in the skin and that found in the oral mucosa has been found by Steigmann.1 Gingival depigmentation is a periodontal plastic surgical procedure whereby the gingival hyperpigmentation is removed or reduced and esthetics is improved.2 An adequate thickness of periodontal tissue is a pre-requisite. Treatment of gingival melanin pigmentation can be done using scalpel, chemical agents, abrasion, grafts, electro surgery, cryosurgery or lasers.3

Clinical crown lengthening procedures are recommended in patients with high smile line, with excess gingival display at rest and to rehabilitate cases with short clinical crowns, extensive caries, traumatic injuries or severe parafunctional habits. Crown lengthening can be limited to the soft tissues when there is enough gingiva coronal to the alveolar bone, allowing for surgical modification of the gingival margins without the need for osseous recontouring. For these cases gingivectomy is recommended.4 Clinical crown lengthening procedures also provide a reasonable compromise for cases with vertical maxillary excess where the patient is not ready for maxillary surgery.5

A maxillary midline diastema is often complicated by labial frenum inserting into a notch in the alveolar bone in such a way that heavy fibrous tissue band lies between the central incisors. Such cases require frenectomy with properly coordinated with orthodontic treatment for successful outcome. Frenectomy should be carried out after orthodontic alignment is done. Frenectomy procedure involves a simple incision followed by removal of fibrous connection to bone and suturing of frenum at a higher level.6

Irregular gingival contours and curvature requires corrective periodontal surgery post orthodontic treatment to further enhance esthetics. The visibility of the gingival level on smiling serves as the indicator for the necessity of corrective periodontal surgery to place the gingival margins in their appropriate position.7

 

 

Conservative and restorative procedures improving orthodontic treatment outcome

 

Congenitally missing maxillary lateral incisors can be managed with three treatment options. These options are canine substitution, a tooth-supported restoration, and a single-tooth implant. Tooth supported restoration can be of 3 types including resin bonded fixed partial denture (FPD), cantilever FPD and a conventional full coverage FPD. Other options include removable partial dentures, resin-bonded bridges, orthodontic repositioning to close the space. The minimally invasive treatment that satisfies the patient's esthetic needs and provides appropriate function should be the selected treatment.8

 

a)     Canine substitution

A relatively straight profile is considered ideal or even one with a slightly convex profile may be appropriate but a patient with a convex profile, retruded mandible and deficient chin prominence are inappropriate for canine substitution. There are two types of malocclusion that permit canine substitution viz. Angle class II malocclusion with no crowding in mandibular arch and Angle class I malocclusion with sufficient crowding to necessitate mandibular extractions. Assessment of shape, color, and crown width at the canine's cement-enamel junction should also be considered. The ideal replacement for the lateral incisor would be a canine which is similar to central incisor in color, slightly narrower at the cement-enamel junction and mid-crown along with a flat labial contour. It may be necessary to restore mesioincisal and distoincisal edges in order to recreate normal lateral contours depending upon the amount of wear of the canine and bleaching might also be necessary to attain an optimal color, as canine is usually 1-2 times more saturated with color.9

 

b)     Orthodontic space closure

The main advantage of space closure is that after finishing the orthodontics, no retainers are needed to maintain the space and permanence of the finished result and the possibility to complete the treatment in early adolescence.10The only restorations that may be needed are porcelain veneers if the teeth cannot be conservatively reshaped. Bleaching may be enough to correct shade. A palatal splint may be required for retention. The disadvantage is that a canine-protected occlusion cannot be established and some compromise in esthetics.11. Space closure can create a problem in matching size, shape, and color especially in cases of unilateral agenesis. The problem usually occurs because the canine normally is more in dimension both mesiodistally and labiolingually and more saturated with color than the lateral incisor it will replace. However, the first premolar is usually shorter and narrower than the contralateral canine. The esthetic outcome will be optimal and pleasing only when these differences are compensated for.11

 

For a natural looking smile, lithium silicate veneers on maxillary canines can be considered for use in cases of congenitally missing maxillary lateral incisors after orthodontic space closure is achieved.12

 

Fluorosed teeth require special considerations during and post orthodontic treatment completion. It manifests as an extensive hypo mineralized subsurface layer underneath an outer well mineralized acid-resistant surface layer.13 It is this outer layer which prevents effective etching with conventional 37% phosphoric acid and results in inconsistent etch patterns and an unreliable enamel surface for orthodontic bonding.14 Adhesion promoters provide a reliable chemical bond in such cases. The promoter consists of the primer, which is often an aqueous solution of HEMA and a polyalkenoic acid that assists with moisture control thereby allowing the resin layer to flow or 'wet' the etched surface and an adhesive is often a Bis-GMA and HEMA resin combined with a blend of amines, which provides a fast, 10-second cure when activated by a visible light curing unit. This kind of chemical adhesion to enamel has been claimed to result in less micro-leakage and a superior hermetic seal.15

 

In cases of microdontia which generally presents with spacing, orthodontic treatment usually involves redistribution on spaces followed by crown preparation and individual esthetic crowns on all the affected teeth. Composite build ups for the affected individual teeth can also be considered in these cases.

 

Attrited or worn out incisal edges must be considered during orthodontic treatment planning for orthodontic extrusion followed by trimming the incisal edges to a proper level or for composite build up. The bite depth and gingival margin level must be taken into account when deciding for occlusal trimming or composite build up.

 

 

Prosthodontic procedures potentiating the orthodontic treatment outcome

 

The missing lateral incisor could be restored with a traditional fixed partial denture (FPD), a resin-bonded prosthesis, implant, or a removable prosthesis. Metal-ceramic or all-ceramic FPD are two esthetic options available, of which all-ceramic bridge is better as it will eliminate the grey hue that may occur with the use of a metal collar. Reforming the lost papilla and creating an ovate pontic is a crucial step in eliminating black triangles.16

 

Resin-bonded FPDs is yet another esthetic option. However, possible graying of the abutment teeth and show through of the metal retainer are the main disadvantages. It is contraindicated in deep bite cases as the area available for retention is less and lateral forces are more.17

 

The lateral incisor also can be cantilevered off the canine with full coverage on the canine or possibly pin retention.8

 

Although high survival rates for implants and implant-supported crowns can be expected, biologic and technical complications are frequent, and may appear even after only a few years.18-20 Even small tooth movements after implant placement can cause esthetic problems.17,20-24 Progressive infraocclusion can occur after some years because of the continuous eruption of adjacent teeth, even in adults and elderly patients.17-21 Blue coloring of the gingiva and resorption of the labial bone have been reported.15The frequent lack of complete gingival papillary fill-around implant crowns might also have estheticconsequences.18-19Bone loss on neighbouring teeth was shown in a follow up study of implant-supported-crowns replacing maxillary incisors.21

 

Amongst all the above, Space-closure serves as a good alternative when orthodontic treatment is properly combined with techniques from esthetic dentistry.25,27-28

This technology can include the following:

 

a)      Careful correction of the crown torque of mesially relocated canines to match the optimal lateral incisor crown torque, along with providing optimal torque and rotation for the mesially moved premolars.

b)      Intentional bleaching or a porcelain veneer to transform any yellowish or dark canines to provide it an optimal lateral incisor shade

c)      Individualized extrusion of canine and intrusion of first premolar during their mesial movement, to attain optimal marginal gingival contours of the anterior teeth.

d)      Length and width of the intruded first premolars should be increased with porcelain veneers or resin buildups.

e)      Simple minor surgical procedures for localized clinical crown lengthening.

f)       Evaluation and eventual restoration the central incisors in case they are small in size too as commonly seen in patients with lateral incisor agenesis. This has an added advantage of providing more optimally display of the dentition during speech and smiling.

Discussion

Before deciding for the adjunctive procedure to be followed for esthetic enhancement during orthodontic treatment planning, pros and cons of all the possible procedures should be considered. After discussing these aspects, the procedure with minimal risk and maximum benefit must be followed after taking informed consent from the patient. Among periodontal plastic surgery procedures for gingival depigmentation, most economic and commonly followed technique is using the scalpel. Recent reports on treatment of gingival melanin pigmentation using cryosurgery and lasers show results to be far superior to other techniques in terms of ease of use, acceptance and patient comfort.3

In cases where clinical crown lengthening is suggested, the timing of gingival surgery is debatable. As gingival harmony may be influenced by extrusion or intrusion of teeth, orthodontic treatment typically precedes periodontal therapy. The definitive diagnosis of the type of gummy smile determines the treatment. If the clinical crowns are short as a result of altered passive eruption, clinical crown lengthening should be performed before orthognathic surgery.29 However, a two-phase approach has been suggested by Garber and Salama which involves initial gingival surgery before the orthognathic procedure, with a second possible alteration of gingival display following orthognathic surgery.30

Yet another group of cases are indicated for gingivectomy provided the osseous level is appropriate, if there is more than 3 mm of tissue from bone to gingival crest and if it is determined that an adequate zone of attached gingiva will remain after surgery.29 However if the diagnostic procedures reveal osseous levels approximating the CEJ, a gingival flap with ostectomy is indicated. In cases where preoperative tissue contours are symmetric, a sulcular incision can be used and the flap apically repositioned whereas cases with asymmetric gingival contours are first treated with gingivectomy-type incision so as to achieve a final symmetric.7 Gingivectomy results in gingival rebound and a need for additional surgery whereas flap appears to be the best approach as it maximizes therapeutic benefit while reducing the tissue morbidity and risk.31

During orthodontic treatment oral hygiene must be maintained properly and regular scaling must be performed to avoid the problems of inflammatory gingival enlargement which are of serious esthetic concern. A drastic reduction in gingival hyperplasia is however demonstrated 48 hours after appliance removal.32 Gingival enlargements due to other reasons like drug induced gingival enlargement must also be given additional attention and patient's physician must be consulted for the possible substitution of the responsible drug with other drug which have little or no effect on gingiva.

The timing of frenectomy for cases with high labial frenal attachment is closely related to the size of diastema present. If the diastema is relatively small, it is usually possible to orthodontically close the space completely between central incisors before frenectomy. However if the diastema is large and the frenal attachment is thick, it may not be possible to completely close the space orthodontically before surgical intervention. In such cases the spaces should be at least partially closed and orthodontic treatment to close the diastema should be resumed immediately after frenectomy to avoid the problems associated with scar tissue that forms as the healing progresses.6 

Amongst all the options for cases of congenitally missing teeth, space-closure serves as a good alternative when orthodontic treatment is properly combined with techniques from esthetic dentistry rather than considering canine substitution. Though single implants have high survival rates, it has several disadvantages. The disharmonious marginal gingival levels resulting from infrapositioned implant crowns are a disadvantage for patients with a high smile line. Gummy smile therefore is a contraindication for implants in the anterior maxilla.25 The marginal and interdental gingival tissue surrounding an implant crown is unlikely to remain unchanged over a long time span. Gingival recession might occur from overzealous tooth brushing or periodontal disease in adult and elderly patients and this would result in a darkening effect along the exposed implant crown thereby leading to unaesthetic consequences.11 The consideration of riding pontic serves to be useful in cases of missing teeth and also in extraction cases to avoid the periods of partial edentulousness and to boost up patient's confidence by providing such esthetic alternative.

Fluorosed teeth requires special attention during orthodontic bracket bonding like use of adhesion promoters to improve the hermetic seal and reduce micro leakage as the outer acid resistant enamel layer in such cases prevents proper etching. The subsurface hypo mineralized layer of fluorosed enamel manifests itself as unsightly white or brown discolorations occurring as pits, striations, or white opaque lines posing an esthetic concern for patients, in whom composite or laminate veneers are recommended to potentiate esthetics after the completion of orthodontic treatment.14

 

Conclusion

Integration of orthodontic treatment with various disciples thus provides a pleasant and esthetic outcome in certain conditions which is not possible otherwise with orthodontic therapy alone. Ultimately orthodontic treatment planning must include evaluation of gingival health, missing teeth, fluorosed teeth, all the other parameters of esthetics and thereby anticipate the need for various adjunctive multidisciplinary procedures to provide patients the option of an optimal esthetic smile.

 

References

1.        Steigmann S. The relationship between physiologic pigmentation of the skin and oral mucosa in Yemenite Jews. Oral Surg Oral Med Oral Pathol. 1965;19:32-38.

2.       Anoop S, Abraham S, Ambili R, Mathew N. Comparative evaluation of gingival depigmentation using scapel and diode laser with 1 year follow up. Int J Laser Dent 2012;2(3):87-91.

3.       Kumar S, Bhat GS, Bhat KM. Development in techniques for gingival depigmentation -An update. Indian J Dent 2012;3(4) :213-221.

4.      Dibart S and Karima M. Practical Periodontal Plastic Surgery, Ames, Iowa (USA): Blackwell Publishing Professional; c2006. Chapter15, Improving Patients' Smiles: Aesthetic Crown-Lengthening Procedure; p.99-104.

5.       Redlich M, Mazor Z, Brezniak N. Severe high angle Class II Division 1 malocclusion with vertical maxillary excess and gummy smile: a case report. Am J Orthod Dentofacial Orthop1999; 116(3):317-20.

6.      Edwards JG. Soft tissue surgery to alleviate orthodontic relapse. Dent Clin North Am 1993;37:205-225.

7.       Foley TF, Sandhu HS, Athanasopoulos C. Esthetic Periodontal Considerations in Orthodontic Treatment -The Management of Excessive Gingival Display. J Can Dent Assoc 2003; 69(6):368-72

8.      Kokich VO, Kinzer GA, Janakievski J. Congenitally missing maxillary lateral incisors : Restorative replacement. Am J Orthod Dentofacial Orthop 2011;139(4): 434-45.

9.      Kokich VO, Kinzer GA. Managing congenitally missing lateral incisors. Part I: Canine Substitution. J Esthet Restor Dent. 2005;17:1-6.

10.    Zachrisson BU, Rosa M, Toreskog S. Congenitally missing maxillary lateral incisors: Canine substitution. Am J Orthod Dentofacial Orthop 2011; 139(4):434-45.

11.     Sabri R. Management of missing maxillary lateral incisors. J Am Dent Assoc. 1999;130:80-84.

12.    Ferencz JL. An Aesthetic Application for lithium disilicate. Treatment of Missing Maxillary Lateral Incisors and Canine Substitution. Dent Today. 2012; 31(12): 48, 50-1.

13.    Miller RA: Bonding fluorosed teeth: new materials for old problems. J Clin Orthod 1995;29:424-427.

14.    Wiltshire WA, Noble J. Clinical and Laboratory Perspectives of Improved Orthodontic Bonding to Normal, Hypoplastic, and Fluorosed Enamel. Semin Orthod 2010;16:55-65.

15.    Noble J, Karaiskos N, Wiltshire WA: In vivo bonding of orthodontic brackets to fluorosed enamel using an adhesion promoter. Angle Orthod 2008;78:357-360.

16.    Priest GF. Esthetic comparison of alternatives for replacement of a single missing tooth. J Esthet Restor Dent. 1996;8(2):58-65.

17.    Kinzer GA, KokichJr VO. Managing congenitally missing lateral incisors. Part II: tooth-supported restorations. J Esthet Restor Dent. 2005;17(2):76-84.

18.    Jung RE, Pjetursson BE, Glauser R, Zembic A, Zwahlen M, Lang NP. A systematic review of the 5-year survival and complication rates of implant-supported single crowns. Clin Oral Implants Res 2008;19:119-30.

19.    Dueled E, Gotfredsen K, Damsgaard MT, Hede B. Professional and patient-based evaluation of oral rehabilitation in patients with tooth agenesis. Clin Oral Implants Res 2009;20:729-36.

20.   Engeseth I. Mutilating dental traumas: outcome of treatments involving orthodontics, transplantation, implants, and prosthodontics [thesis]. Oslo, Norway: University of Oslo; 2009. p. 1-45.

21.    Thilander B, Odman J, Lekholm U. Orthodontic aspects of the use of oral implants in adolescents: a 10-year follow-up study. Eur J Orthod 2001;23:715-31.

22.   Bernard JP, Schatz JP, Christou P, Belser U, Kiliaridis S. Longterm vertical changes of the anterior maxillary teeth adjacent to single implants in young and mature adults. A retrospective study. J Clin Periodontol 2004;31:1024-8.

23.   Jemt T. Measurements of tooth movements in relation to single implant restorations during 16 years: a case report. Clin Implant Dent Relat Res 2005;7:200-8.

24.   Jemt T. Single implants in the anterior maxilla after 15 years of follow-up: comparison with central implants in the edentulous maxilla. Int J Prosthodont 2008;21:400-8.

25.   Rosa M, Zachrisson BU. The space-closure alternative for missing maxillary lateral incisors: an update. J Clin Orthod 2010;44:540-9.

26.   Chang M, Wennstrom JL, Odman P, Andersson B. Implant supported single-tooth replacements compared to contralateral natural teeth. Crown and soft tissue dimensions. Clin Oral Implants Res 1999;10:185-94.

27.   Rosa M, Zachrisson BU. Integrating esthetic dentistry and space closure in patients with missing maxillary lateral incisors. J Clin Orthod 2001;35:221-34.

28.   Rosa M, Zachrisson BU. Integrating esthetic dentistry and space closure in patients with missing maxillary lateral incisors: further improvements. J Clin Orthod 2007;41:563-73.

29.   Dolt AH 3rd, Robbins JW. Altered passive eruption: an etiology of short clinical crowns. Quintessence Int1997; 28(6):363-72.

30.   Garber DA, Salama MA. The aesthetic smile: diagnosis and treatment. Periodontol 2000 1996; 11:18-28.

31.    Thomas C. Waldrop. Gummy Smiles: The Challenge of Gingival Excess: Prevalence and Guidelines for Clinical Management. Semin Orthod 2008;14:260-271.

32.   Krishnan V, Ambili R, Davidovitch Z, Murphy NC. Gingiva and the orthodontic treatment. Semin Orthod 2007;13:257-271.