Etiology and Treatment of Midline Diastema: a Review of Literature

REVIEW ARTICLE POJ 2013:5(1) 27-33

Etiology and treatment of midline diastema: A review of literature

Umar Hussaina, Ali Ayubb, Muhammad Farhanc

Abstract Introduction: Midline diastema can be physiological, dentoalveolar, due to a missing tooth, due to peg lateral, midline supernumerary teeth, proclination of the upper labial segment, prominent frenum or due to a self-inflicted pathology by tongue piercing. The treatment involves observation and follow up, active orthodontic tooth movement, combined orthodontic and surgical approach, restorative treatment and Mulligan’s technique of overcorrection. Material and Methods: Hand and electronic searching was done for 55 articles for this review of literature. Results: Midline diastema is common dental anomaly having multiple causes and various orthodontic and surgical options for management. Conclusions: Midline diastemas require proper diagnosis and timing for better care of patients. Keywords: spacing; gap; diastema causes

Introduction The extent and the etiology of the diastema must be properly evaluated. In some cases space between adjacent teeth is called a interceptive therapy can produce positive A “diastema”. Midline diastemata (or results early in the mixed dentition. Proper diastemas) occur in approximately 98% of 6 case selection, appropriate treatment year olds, 49% of 11 year olds and 7% of 12– selection, adequate patient cooperation, and 18 year olds.1 In most children, the medial good oral hygiene all are important.8-10 erupting path of the maxillary lateral incisors Eruption, migration and physiological and maxillary canines, as described by readjustment of the teeth, labial and facial Broadbent results in normal closure of this musculature, development into the beauty- space.2 In some individuals however, the conscious teenage group, the anterior diastema does not close spontaneously. The component of the force of occlusion and the continuing presence of a diastema between increase in the size of the jaws with the maxillary central incisors in adults often is accompanying increase in tonicity of the facial considered an esthetic or malocclusion musculature all tend to influence closure of problem.3 Midline diastema’s can be the midline dental space.11 The mandibular physiological, dentoalveolar, due to a missing diastema is not a normal growth tooth, due to peg shaped lateral, midline characteristic. The spacing, though seen less supernumerary teeth, proclination of the frequently than maxillary diastema, often is upper labial segment, prominent frenum and more dramatic. No epidemiologic data have due to a self-inflicted pathology by tongue been published on its prevalence. The piercing.4,5 Angle and Sicher6 stated that an primary etiologic factor in mandibular abnormal frenum is a cause of midline diastema is tongue thrust in a low rest diastema, while Tait7 in his study reported position.12 that frenum is an effect and not a cause for Many patients seek closure of a diastema for the incidence of diastema. aesthetic reasons. In the case of normal a,c BDS; House Officer in Khyber college of dentistry. physiological development, diastemas of less b BDS, FCPS; Lecturer in orthodontics KCD Peshawar. than 2mm in nine-year-old children generally 27

POJ 2013:5(1) 27-33 close spontaneously.13 If they do not do so, Discussion small diastemas (less than 2mm) can be The midline diastema is a space (or gap) closed with finger springs on a removable greater than 0.5mm between the mesial appliance or with a split Essix plate, as surfaces of maxillary central incisors. The described by Sheridan.14 In adults with wider space can be a normal growth characteristic diastemas, fixed appliances are required for during the primary and mixed dentition and correction so that crown and root angulations generally is closed by the time the maxillary are controlled.15 canines erupt. For most children, with the The etiology, pathogenesis and diagnosis of eruption of canine normal closure of this maxillary median diastema have been somewhat controversial over the years. The space occurs. For some individuals, however, 16 purpose of this paper is to review the the diastema does not close spontaneously. published information and controversies Midline diastema’s can be genetical, regarding the etiology and treatment of the physiological, dentoalveolar, due to a missing midline diastema in order to give the tooth, due to peg shaped lateral, midline practitioner an overview to direct effective supernumerary teeth, proclination of the diagnosis and treatment. upper labial segment, prominent frenum and due to a self-inflicted pathology by tongue Material and Methods piercing.17,18 Computer databases, including PubMed, Midline spacing has a racial and familial Science direct and Google advance search background.19 Although no specific genes were searched. Internationally published have been investigated for its genetic research literature, review articles and etiogenesis but there are many syndromes relevant citations were included. After the and congenital anomalies which contained electronic literature search, a hand search of midline diastema one of their component e.g. key orthodontic journals was undertaken to Ellis-van Creveld syndrome,20 Pai Syndome,21 identify recent articles. The review was lateral incisor agenesis22 and cleft restricted to articles dealing with the etiology palate,23median cyst.24 and management of maxillary midline Midline diastema may be considered normal diastema. Exclusion criteria included articles for many children during the eruption of the that did not follow the objective of this review permanent maxillary central incisors. When and articles in a language other than English. the incisors first erupt, they may be separated by bone and the crowns incline distally Results because of crowding of the roots. With the A broad search of published articles (The eruption of lateral incisors and permanent Angle Orthodontist, American Journal of canines, midline diastema reduces or even Orthodontics and Dentofacial Orthopedics, closes (ugly duckling stage).25 British Dental Journal, European Journal of A maxillary midline diastema may be caused Orthodontics, Journal of clinical pediatrics, by the insertion of the labial frenum into the Journal of Oral Pathology Pakistan oral and notch in the alveolar bone, so that a band of Dental Journal, Journal of dental association) heavy fibrous tissue lies between the central was done using both the electronic database incisors.26 The two central incisors may erupt and hand searching. A total of 55 studies widely separated from one another and the were retrieved initially. 45 studies were rim of bone surrounding each tooth may not closely related to study objective were used to extend to the median suture. In such cases, no write the review of literature for the etiology bone is deposited inferior to the frenum. A V- and management of midline diastema. shaped bony cleft develops between two

POJ 2013:5(1) 27-33 central incisors, and an "abnormal" frenum suture but it is temporary and closes by itself attachment usually results.27 Transseptal in most cases.38 fibers fail to proliferate across the midline An open midpalatal suture or skeletal cleft cleft, and the space may never close.28 Angle may prevent normal space closure and and Sicher stated that an abnormal frenum is present as midline diastema.3 a cause of midline diastema,29,30 while Tait in An object can deflect the eruption pattern of his study reported that frenum is an effect the maxillary central incisors or physically and not a cause for the incidence of move diastema.31 the incisors laterally to create midline V-shaped midline bony clefts may interrupt spacing. Examples include: the formation of transseptal fibers and have Retained primary tooth, midline pathology been suggested as a cause of diastemas. (cysts, fibromas), Foreign body and associated Higley32 suggested that a slight cleft of periodontal inflammation intercrestal bone can hold the teeth apart. Moyers stated that imperfect fusion at the Orthodontic relapse has been correlated with midline of premaxilla is the most common severity of maxillary bony notching.33 cause of maxillary midline diastema. The Patients with supernumerary teeth had normal radiographic image of the suture is a delayed or failed eruption of permanent teeth, V-shaped whereas inverted supernumeraries were more Structure.11 likely to be associated with bodily Because of the potential for multiple displacement of the permanent incisors, etiologies, the diagnosis of a diastema must median diastema and torsiversion.11 be based on a thorough medical/dental Conditions associated with tooth size-arch history, clinical examination, and length discrepancy such as anodontia, radiographic survey. Diagnostic study oligodontia, microdontia, peg shaped laterals, models also may be necessary for analysis macrognathia may cause midline diastema. If and measurement when the diastema may be due to malocclusion, or tooth and/ arch size the lateral incisors are small or absent, the discrepancy. The medical/dental history extra space can allow the incisor teeth to should investigate any pertinent medical move apart and create a diastema.34 conditions (such as hormonal imbalances), Prolonged pernicious habits can change the oral habits, previous dental treatment and/or equilibrium of forces among the lips, cheeks, surgeries, and family history of diastemas or and tongue and cause unwanted dentofacial other related dental problems. The clinical changes tooth movement.35 The outward exam should include evaluation of possible pressure from prolonged oral habits (light pernicious oral habits, soft tissue imbalances continuous force over 6 hr) with inadequate (e.g., macroglossia), improper dental lips seal can cause the maxillary incisors to alignment (rotated teeth, excessive flare out, which leads to the midline overbite/overjet), missing teeth, or other diastema. Examples include: lower lip biting dental anomalies. The "blanching test" may be and digit sucking.36 used to evaluate the frenal attachments. Conditioncs such as macroglossia, tongue Panoramic and periapical radiographs are thrust, improper tongue rest position, and/or necessary to evaluate the patient's dental age flaccid lip muscles can caused midline and any physical impediments, abnormal diastema.37 suture morphology, missing teeth, dental Rapid maxillary expansion can cause midline anomalies, improper dental alignment, or diastema due to opening of the intermaxillary abnormal eruption paths. In some instances,

POJ 2013:5(1) 27-33 complete orthodontic records and a Bolton's orthodontic appliances. A removable Hawley analy sis39 may be necessary to rule out appliance with finger springs is commonly skeletal/dental malocclusions as well as used. Simple fixed appliances often have been possible jaw size and/or dental size used.44,45 These devices involve a U- or V- discrepancies. shaped sectional wire and some double- Persisting midline diastemas are often seen by helical closing loops and are bonded directly dentists in people seeking esthetic to the incisors or attached to lingually bonded improvement. A study by Kerosuo40 reports tubes. Micromagnetic devices have been that people with significant anterior crowding described.46 These fixed appliances also can or midline diastema were very frequently serve as post-treatment retainers. Diastema considered less intelligent, beautiful and closure in these cases should be deferred until sexually attractive and were perceived to be the canines erupt. of a lower social status in comparison to the In certain instances closing a diastema same individuals when they had excellent requires bodily approximation of the incisors. occlusion. Rosenstiel and Rashid41 in an Full banded/bracketed orthodontic arch Internet study concerning the opinion of lay appliances can move incisors bodily to close people about anterior teeth esthetics, showed the space. However, if time or cost factors that conditions such as diastema and midline prohibit this type of treatment, or if the deviation received the worst ratings. Detailed diastema is the only malocclusion needing analysis and understanding of malocclusion treatment, sectional arch wire techniques are is needed by the orthodontist, so that he/she a useful alternative.47 This technique involves may successfully treat midline diastema for bonding brackets directly on the four the patient’s esthetic and functional benefit. maxillary incisors and using a 0.018- in. Before the practitioner can determine the sectional wire. An elastomeric chain or elastic optimal treatment, he or she must consider thread should be placed from the mesial wing the contributing factors. These include normal of one lateral incisor bracket through the growth and development, toothsize brackets of the centrals to the mesial wing of discrepancies, excessive incisor vertical the other lateral. Overstretching the overlap of different causes, mesiodistal and elastomeric chain can cause unwanted mesial labiolingual incisor angulation, generalized rotation of the lateral incisors if the spacing and pathological conditions.42 A elastomeric chain is connected from the distal carefully developed differential diagnosis wing of one bracket to the distal wing of the allows the practitioner to choose the most other. Treatment with a "2x4 appliance” or effective orthodontic and/or restorative utility arch can provide better control of treatment. Diastemas based on tooth-size incisors during closure of the midline spaces discrepancy are most amenable to restorative and also can retract any minor incisor flaring. and prosthetic solutions.43 The most Although treatment is best delayed until appropriate treatment often requires canine eruption, it can be initiated after the orthodontically closing the midline diastema. lateral incisors have erupted. The following treatment options are in Many cases of protruded maxillary incisors practice. demonstrate overeruption of the incisors in In some cases, orthodontic closure of the both arches. Decreasing the overjet by simply diastemas is limited to the central incisors. In moving the incisors lingually can cause a patients with good posterior occlusion or who significant occlusal contact. Removable have economic considerations, the diastema appliances often will cause this unwanted can be closed simply with removable overbite and should be used carefully and

POJ 2013:5(1) 27-33 only in patients with minimal overbite and the timing for a frenectomy. Some when the maxillary incisors are not in contact orthodontists support a viewpoint that there with mandibular incisors. Hawley-type is a need for an early removal of the frenum, retainers with a labial bow and clasps are so as to prevent any obstacles to complete useful for this limited therapy. In most cases diastema closure. Other orthodontists of increased overjet, treatment requires the propose to close the diastema first, and then use of a full-arch fixed appliance technique to carry out frenectomy in the hope that the intrude the incisors while closing the resultant scar tissue will hold together the diastema. Both arches may require treatment. teeth in close apposition. A third body of In some of these cases headgear may be clinicians rarely, if ever, considers surgical needed for appropriate anchorage. removal of the frenum. They prefer to combat In general, fixed-type appliances can provide the undeniably increased relapse potential better control in crown/root angulation, when a diastema is closed, by using bonded overbite, and overjet. Bracketed/banded retainers on the two central incisors.50 appliances can close diastemas due to The indications for surgical removal of the improper tooth inclination, deleterious maxillary midline frenum are usually the occlusal patterns, posterior bite collapse, deep following; prevention of median diastema bite with insufficient torque, or skeletal formation, prevention of post-orthodontic and/or dental class II division 1 relapse of a median diastema, facilitation of malocclusion.48 Some patients may need to oral hygiene, prevention of gingival wear a headgear or Class II elastics to recession.51 distalize the posterior teeth. Class I Various surgical techniques have been relationships should be achieved before the proposed by clinicians. The simplest method diastema is closed. Removable orthodontic is performed with two parallel incisions on appliances can be used cautiously in diastema each side the frenum joined in the vestibule cases with Class I dental and/or skeletal by a scissor cut. The wound edges are closed relationship and mild or acceptable overbite. with a single suture.51 this technique, known Management of maxillary midline diastema as a V-shaped incision., is reported to leave a with missing lateral incisor in early mixed scar contracture that can lead to periodontal dentition by 2×4 appliance49 included closure problems, as well as loss of the interdental of space between maxillary central incisors, papilla between the maxillary central space created between permanent central incisors.52 other techniques are Z-plasty, incisor and deciduous canine to be closed by Vestibular sulcus extension and prosthetic replacement. Maxillary permanent Morselli’procedure. Last three techniques canines to be guided in the place of lateral associated with less scar formation but incisor and achievement of appropriate surgically demanding. canine and molar relationship. Alternative It is important to mention that there are treatment based upon the proclination of restorative solutions (veneers, crowning and anterior teeth and molar occlusion, either composite buildup) to these cases without canine could be retained in lateral incisor orthodontic intervention. However, position and molar relationship finished in restorative measures are more likely to be class II, or canine moved into its place and appropriate in adults and are also subject to molar relationship finished in class I with on-going maintenance issues. Care must be replacement of missing lateral incisors. taken that the emergence profile of any There has been a controversy even among restoration is not over-contoured creating orthodontists concerning the need at all, and hygiene problems. Care must also be taken

POJ 2013:5(1) 27-33 with the crown width/length ratio. Maxillary References midline spacing can also be reduced or 1. Foster TD, Grundy MC. Occlusal changes from temporarily closed with composite resin primary to permanent dentitions. J Ortho. 1986; 13: directly on the proximal surfaces of teeth 187–93. adjacent to the space without bonding agent 2. Broadbent BH: The face of the normal child (diagnosis, development). Angle Orthod 1937; prior to orthodontics. It may then be removed 7:183-208. as tooth movement proceeds. When 3. Adams CP: Relation of spacing of the upper combined orthodontic-restorative treatment is central incisors to abnormal frenum labii and planned, collaboration between the other features of the dentofacial complex. Am Dent J.1954; 74:72-86. orthodontist and the restoring dentist should 4. Edwards JG. The diastema, the frenum, the begin at the diagnostic phase.53 frenectomy a clinical study. Am J Orthod 1977; 71: A bonded palatal fixed retainer (on two 489–508. central incisors or canine to canine) is 5. Rahilly G, Crocker C. Pathological migration: an unusual cause of midline diastema. Dent Update advisable in the majority of cases to stabilise 2003; 30(10): 547–9. the post treatment result. In wider diastemas 6. Sicher H. Oral anatomy. 2nd ed. The C.V. Mosby Co: this retention should be permanent. As with St. Louis; 1952. p. 185,272-3. all bonded retainers patients should be 7. Tait CH. The median frenum of the upper lip and its influence on the spacing of the upper central instructed in good oral hygiene, including the incisor teeth. Dent Cosmos 1934; 76:991-2. use of floss threaders. The authors generally 8. Huang WJ, Creath CJ. The midline diastema: a provide patients who have bonded retainers review of its etiology and treatment. Pediatr with a removeable Hawley-type retainer to be Dent.1995; 17: 171–9. 9. Proffit W, Fields H. Contemporary Orthodontics. worn at night for the first few years. 3rd ed. Mosby, St. Louis.2000; 429–30. Mulligan48 in a recent report presents a novel 10. Bishara SE. Management of diastemas in method of reducing retention requirements in orthodontics. Am J Orthod.1972; 61: 55–63. 1972. these cases. He moves the apices of the 11. Kumar LN, Nagmode P. Midline Diastema: treatment Options. J Evolution of Medical and incisors distally in finishing the treatment. In dental Science.2012; 1(6):1262-6. this way, he postulates, larger functional 12. Attia Y: Midline diastemas: closure and stability. moments are produced when the incisor roots Angle Orthod 63:209-12, 1993. are divergent which help to keep the 13. Bishara SE. Textbook of Orthodontics. 1st ed.Elseviere. 2006.155-6. diastema closed. To test the stability he 14. Sheridan J, Hilliard K, Armbuster P. Essix removed the archwires for a six-weeks period Appliance Technologies: Applications, Fabrications near the end of treatment. The disto-incisal and Rationale. Am Dent J . 2003; 66:123-7. edges of the tipped teeth are modified with 15. Proffit WR, Fields HW. Contemporary Orthodontics. 4th ed .Mosby.2007; 569-75. the use of disks for enhanced aesthetics. This 16. Proffit WR, Fields HW. Contemporary interesting approach holds promise. Orthodontics. 4th ed .Mosby.2007;99-100. 17. Ewards JG. The diastema, the frenum, the Conclusions frenectomy a clinical study. Am J Orthod 1977; 71: • Etiology of midline diastema is 489–508. multifactorial. 18. Qazi SH, Attaullah K. Treatment of midline • diastema – multidisciplinary managment: a case Proper diagnosis and timing is the report.Pak ortho J.2009;1(1):23-7. important part of management. 19. Gass JR, Valiathan M, Tiwari HK, Hans MG, Elston • Management options are observation and RC. Am J Orthod Dentofacial Orthop. 2003 follow up, orthodontic treatment, Jan;123(1):35-9. frenectomy and space closure and 20. Hattab FN, Yassin OM, Sasa IS. "Oral restorative treatment. manifestations of Ellis-van Creveld syndrome: report of two siblings with unusual dental • Permanent retention is the most important anomalies." The Journal of clinical pediatric part of treatment. dentistry 1998;22(2): 159-65.

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21. Mishima K, Mori Y, Minami K, Sakuda M 38. Oliveira D, Felippe, Nanci L . "Relationship ,Sugahara T. (1999). A case of Pai syndrome. Plastic between rapid maxillary expansion and nasal and reconstructive surgery.1999;103(1): 166-70. cavity size and airway resistance: short-and long- 22. De Coster PJ, Marks LA, Martins LC, Hysseune A. term effects." American Journal of Orthodontics Dental ageneses: Genetic and clinical perspective. J and Dentofacial Orthopedics 2008;134(3) : 370-82. Oral Pathol Med 2009;38:1-17. 39. Bolton WA: Clinical application of a tooth-size 23. Tang EL, So LL. Prevalence and severity of analysis. Am J Orthodont.1962; 48:504-29. malocclusion in children with cleft lip and/or 40. Kerosuo H, Hausen H, Laine T, Shaw WC. The palate in Hong Kong. The Cleft palate-craniofacial influence of incisal malocclusion on the social journal,1992; 29(3): 287-91. attractiveness of young adults in Finland. Eur J 24. Neville BW, Damm DD, Brock T. Odontogenic Orthod 1995;17:505-12. keratocysts of the midline maxillary region. J Oral 41. Rosenstiel SF, Rashid RG. Public preferences for Maxillofac Surg 1997;55:340-4. anterior tooth variations: a web-based study. J 25. Richardson, Elisha R etal. "Biracial study of the Esthet Restor Dent 2002;14:97- 106. maxillary midline diastema." The Angle 42. Chu FC, Siu AS, Newsome PR, Wei SH. Orthodontist.1973:43(4): 438-43. Management of median diastema. Gen Dent. 26. Kaimenyi JT. Occurance of midline diastema and 2001;49(3):282-7. frenum attachments among school children in 43. Alam Mk.The multidisciplinary management of Nairobi, Kenya. Indian J Dent Res. 1998; 9:67-71. midline diastema. Bangladesh Journal of Medical 27. Dewel BF: The labial frenum, midline, diastema, Science2010;994):224-35. and palatine papilla: a clinical analysis. Dent Clin N 44. Offerman RE: A diastema-closing device. J Clin Am.1966; 10:175-84. Orthod.1984; 18:430-31. 28. Edwards JG: The diastema, the frenum, the 45. Sahafian AA: Bonding as permanent retention after frenectomy: a clinical study. Am J Orthodont closure of median diastema. J Clin Orthod.1978; 1977;71:489-508. 12:568. 29. Angle EH. Treatment of malocclusion of the teeth. 7 46. Springate SD, Sandier PJ: Micro-magnatic retainers: th ed. S.S. White Dental Manufacturing Co: an attractive solution to fixed retention. Br J Philadelphia; 1907; 103-4. Orthod. 1991;18:139-41. 30. Sicher H. Oral anatomy. 2 nd ed. The C.V. Mosby 47. Banker CA, Berlocher WC, Mueller BH: Alternative Co: St. Louis; 1952;272-3. methods for the management of persistent 31. Tait CH. The median frenum of the upper lip and maxillary central diastema. Gen Dent J.1982; 30:136- its influence on the spacing of the upper central 39. incisor teeth. Dent Cosmos 1934; 76:991-2. 48. Mulligan TF. Diastema Closure and Long-term 32. Higley LB: Maxillary labial frenum and midline stability. J Clinical Orthodontics. 2003; 1: 560-74. diastema. ASDC J Dent Child 1969;36:413-14. 49. Ramamurthy S, Ramaswamy S. Management of 33. Bray RJ: The maxillary midline diastema, presented maxillary midline diastema in early mixed before the American Association of Orthodontics, dentition by 2×2 appliance.POJ.2011;2(3):65-8. New York. 1976. 50. Lioliou E, Kostas A, Zouloumis L. The Maxillary 34. Nainar SM, Gnanasundaram N. Incidence and Labial Fraenum -A Controversy of Oral Surgeons etiology of midline diastema in a population in vs. Orthodontists. Balkan south India. Angle Orthod. 1989; 59:277-82. Stomatology.201;16(1):141-46. 35. Moyers RE. Handbook of orthodontic. 4th ed. 51. Kahnberg KE. Frenum surgery. A comparison of 1988;196-218. three surgical methods. J Oral Surg. 1977; 6: 328-33. 36. Huang WJ, Creath CJ. The midline diastema: A 52. Morsell P. Frenuluplasty by triangular flap. J oral review of its etiology and treatment. Pediatric surg.1999; 87;142-44. dentistry.1995;17:171-77. 53. Kavanagh C, Kavanagh D. Maxillary midline 37. Attia Y: Midline diastemas: closure and stability. diastema –aetiology and orthodontic treatment. J of Angle Orthod.1993; 63:209-12. Irrish Dent Assoc.2004;50(1):14-9.