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Year : 2021  |  Volume : 32  |  Issue : 2  |  Page : 250-255
An interdisciplinary approach to management of diastemas: A novel classification and a case report

1 Department of Conservative Dentistry and Endodontics, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India
2 Department of Periodontics, Faculty of Dental Sciences, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India

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Date of Submission01-Oct-2020
Date of Decision19-Dec-2020
Date of Acceptance01-Jun-2021
Date of Web Publication22-Nov-2021


Diastema between the teeth negatively affects the patients' smile, psychology and daily activities by creating a disharmony in the patients' face. The development of diastema has been attributed to several factors such as labial frenulum, microdontia, mesiodens, peg-shaped lateral incisors, agenesis, cysts, habits such as finger sucking, tongue thrusting, or lip sucking, dental malformations, genetics, proclinations, dental-skeletal discrepancies, and imperfect coalescence of interdental septum. Patients often present with complex problems that require a multidisciplinary treatment approach which includes determination of the aetiological factors, soft tissue morphology, occlusion, patient demands and aesthetic consideration to achieve satisfactory outcomes. Lack of current literature on classification of diastemas and multi-disciplinary approach of management led to the proposal of a new classification the ATAC (Anatomic and Therapeutic Classification) for management of the diastema. This case report highlights the use of the proposed classification for management of diastemas, requiring a perio-restorative intervention using a Chu's proportion gauge to achieve ideal aesthetics.

Keywords: Biologic width, biomimetic, composite resin, crown lengthening, diastema, gingival zenith

How to cite this article:
Saeralaathan S, Lavu V, Rajan M, Balaji S K, Ganesh A. An interdisciplinary approach to management of diastemas: A novel classification and a case report. Indian J Dent Res 2021;32:250-5

How to cite this URL:
Saeralaathan S, Lavu V, Rajan M, Balaji S K, Ganesh A. An interdisciplinary approach to management of diastemas: A novel classification and a case report. Indian J Dent Res [serial online] 2021 [cited 2021 Dec 8];32:250-5. Available from:

   Introduction Top

The aesthetic management of diastema is a restorative challenge and may require multidisciplinary approach for a successful outcome. Diastema can be attributed to developmental anomalies, tooth-arch length discrepancy and habits.[1] In clinical practice, patients often present with complex anatomical situations, involving variations in tooth morphology, location of the tooth/gingival margins and loss of inter-dental soft tissue.[2] The treatment options include orthodontic correction, restorative correction using composites, prosthetic correction using veneers/laminates or a combination of the above.[2] An extensive search of the literature till date has revealed an existing classification for midline diastema based on the location and position of teeth, the relation between the proposed contact point and interdental bone level, while the soft tissue position (gingival zeniths and interdental soft tissue location) has not been addressed in this existing classification.[3] Hence, we propose the 'ATAC' (Anatomic and Therapeutic Approach Classification) [Table 1] and [Figure 1] for diastema management involving a restorative-perio approach as elaborated in the following case report.
Table 1: Anatomic and Therapeutic Approach classification (ATAC) for diastema

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Figure 1: ATAC classification

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   Case History Top

A 25-year-old male patient reported to the Department of Conservative Dentistry and Endodontics, with a chief complaint of spacing between the teeth in his upper and lower front teeth. Preliminary examination revealed no facial asymmetry/temporomandibular joint abnormality. Assessment of the lip morphology, lip length and lip line were made. The lip volume was average with a lip symmetry. During resting smile, an incisal show of 3 mm and, on full smile, interdental papilla and 0.5–1 mm of marginal gingiva were visible [Figure 2]a and [Figure 2]b.
Figure 2: Preoperative images of the patient's smile at wide smile (a) and rest (b)

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Intra-oral examination revealed diastemas in the upper and the lower anteriors [Table 2] with a tooth length-to-width ratio discrepancy in the uppers. Overjet and overbite were 4 mm and 3 mm, respectively. Soft tissue examination revealed a high frenal attachment between the maxillary central incisors.
Table 2: Diastema measurements between the tooth in the upper and lower anteriors

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As a part of the preplanning protocol for the gingival zenith correction, an assessment of the following clinical periodontal parameters were made: gingival biotype, probing pocket depth, width of keratinized gingiva/attached gingiva at three sites in the buccal aspect of the teeth [Table 3], bone sounding and biologic width [Table 4]. The proportion gauge (T tip) was used to assess and record the crown dimensions for each tooth from left maxillary canine to right maxillary canine [Figure 3]a, [Figure 3]b, [Figure 3]c, [Figure 3]d, [Figure 3]e, [Figure 3]f. Further analysis of the hard and soft tissue components of the smile was done with photographs and study models. According to the proposed ATA Classification, the clinical scenario in this case report falls under Class 1a [Figure 4]. An interdisciplinary treatment plan involving frenectomy, crown lengthening by flap with ostectomy (to restore the biologic width) followed by diastema closure with composite resins was implemented.
Table 3: Preoperative recordings of the clinical parameters

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Table 4: Biologic width assessment of the maxillary incisors and canines

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Figure 3: Preoperative assessment of tooth proportion using the Chu's proportion gauge with the T-bar tip for teeth numbers (in FDI notation): (a) 13, (b) 12, (c) 11, (d) 21, (e) 22 and (f) 23

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Figure 4: Clinical case criteria as Class 1a under ATA Classification

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A papillary penetrating type of frenal attachment was observed between the central incisors [Figure 5]. Frenectomy was done with a 940-nm diode laser (Ez Lase, Biolase, India), 1.2 W, continuous wave (CW), 400 μm fibre tip in contact mode and no sutures were placed [Figure 5]. Based on the preoperative assessment, crown lengthening was planned. A surgical stent was prepared with clear acrylic in the maxillary study model. The gingival zeniths were recreated at their new position in the stone model with the help of the T tip of the Chu Gauge and the surgical guide was trimmed to this level.
Figure 5: (a) Frenectomy for papillary penetrating type of frenal attachment, (b) with diode laser, 940 nm, continuous wave, contact mode, 1.2 W and 400 μm fibre

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The prepared surgical guide was transferred to place incisions at the new gingival zenith positions in the maxillary arch. This was followed by crevicular incisions and flap reflections to access the underlying bone. The bone sounding tip of the Chu gauge was used next, to determine the amount of marginal and interdental bone to be removed with reference to the incised flap margins, enabling the reestablishment of the biologic width [Figure 6]a, [Figure 6]b, [Figure 6]c.
Figure 6: Surgical crown lengthening: (a) the surgical guide trimmed and placed intraorally, (b) incision placement, (c) flap reflection and osseous reduction with No. 6 round bur and micromotor, (d) placement of bone sounding tip of Chu gauge, (e) suturing 4-0 vicryl and (f) immediate postop showing correct crown height-to-width ratio achieved

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The bone removal was done using a no 6 round bur (SS White, Lakewood, New Jersey) in a slow-speed micromotor handpiece under cold saline irrigation. The bone sounding tip was used to ensure the bone margin was at least 3 mm away from the incised flap margins after ostectomy [Figure 6]d. The immediate postoperative assessment was performed with the Chu gauge to demonstrate the corrected crown height-width ratio in upper right lateral incisor [Figure 6]f. The flap was then approximated with 4-0 vicryl (resorbable) sutures [Figure 6e]. Postoperative medications were prescribed and an uneventful healing was reported at the 3-week postoperative visit [Figure 7].
Figure 7: Three-week postoperative recall after crown lengthening

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Following periodontal procedures, the restorative management of the diastemas was planned. A biomimetic approach was incorporated considering the width/length of the tooth, location of the contact point and the relationship of the contact to the interdental crestal bone, for a predictable outcome. The width of the central incisors was calculated by the width equation and length-to-width proportion.[3] A wax mock-up was made, which served as a patient education model as well as a guide for the restoration.

Quadrant isolation was done with a heavy rubber dam from premolar to premolar. No tooth preparation was done prior to the adhesive procedure. In order to simulate the aesthetic appearance, the most suitable shade A1 was selected (Solare Sculpt, GC, India) by the composite button method, prior to tooth dehydration.[4] The teeth were etched with 37% phosphoric acid (Etching Gel, Kerr, USA) for 30 s, rinsed and air-dried. Universal bonding agent (Solare Universal Bond, GC India) was applied, dried to avoid pooling of the adhesive, and polymerized for 20 s with a LED curing light according to the manufacturer's instructions. With the wax mock up, a putty index was made with addition silicone (Aquasil, Dentsply Sirona, India). This index was then transferred intraorally and a palatal shelf was created with a transparent shade resin. A contoured sectional matrix (Palodent® System, DENTSPLY Caulk, Milford, Delaware, US) was used for the proximal restorations with one end slightly tucked into the sulcus [Figure 8]a, [Figure 8]b, [Figure 8]c, [Figure 8]d, [Figure 8]e. Composite diastema closure was done in the maxillary anteriors. The gingival harmony, smile line, degree of tooth display, tooth inclination and the symmetry were evaluated after removal of the rubber dam. Similarly, quadrant isolation was done for the lower anteriors and a free hand diastema closure with A1 shade composite was done. Finishing was done with proximal strips and ultrafine diamond points in a slow-speed handpiece, followed by 30 fluted tungsten carbide bur. Horizontal and vertical, micro- and macro-anatomy were incorporated in the planar area under magnification (3.5 × magnifying loupes). Polishing of the restoration was carried out using Optrapol (Ivoclar, Vivadent) kit [Figure 8]e. [Figure 9]a, [Figure 9]b, [Figure 9]c, [Figure 9]d shows the preoperative, postsurgical crown lengthening, composite diastema closure and the immediate postoperative profile of the patient.
Figure 8: Composite diastema closure: (a) postsurgical image of maxillary anteriors, (b) quadrant isolation, (c) palatal shelf and proximal margins created using putty index and palodent matrix, respectively, (d) completed composite build-up and (e) finishing and polishing of the restoration

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Figure 9: (a) preoperative, (b) post-crown lengthening, (c) immediate postop after composite build–up and (d) postop full smile

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   Discussion Top

This paper has brought out a new classification (ATAC) for diastema and its management with a perio-restorative approach as its principal concept. The classification proposed has considered the harmony of tooth dimensions and the gingival tissue margins to provide definitive treatment options which can be applied in day-to-day practice by clinicians. The importance of the soft tissue component with respect to the diastema has been overlooked in the previous classification. In the existing classification for the management of diastemas, the position of the interdental soft tissue and the gingival zenith weren't addressed. Also, specific and stable anatomic landmarks were not described in the previous classification.[3]

The Chu's proportion gauge (Hu-Friedy Mfg. Co., Chicago) was chosen as it gives a visual and objective representation of the Recession Esthetic Dental proportion of 78% height-to-width ratio.[5] The instrument has a T-bar tip, has a colour coding for teeth with red for central incisors (8.5 mm in width and 11 mm in length), blue for lateral incisor (6.5 mm width and 8.5 mm length) and yellow for canine (7.5 mm in width and 9.5 mm in length).[5] The in-line tip was not used in this case as there was no crowding and the length and height measurements of the teeth could be measured simultaneously with the T-bar tip. Hence, the Chu's proportion gauge is an ideal instrument enabling quick chairside assessment during preoperative/intraoperative sessions and clear communication between the periodontist and restorative dentist. Frenectomy was done with diode laser (940 nm) using a 400-μm fibre tip to dissect the fibre attachment in the inner aspect of the interdental soft tissue, leaving the outer aspect undisturbed. This preserved the interdental soft tissue during healing and enabled a predictable aesthetics following restoration for diastema closure.

The crown lengthening was performed by flap with ostectomy procedure as there was sufficient width of keratinized gingiva and to ensure restoration of biologic width after healing of the flap. A crown lengthening procedure was required to achieve the ideal crown height-to-width ratio, since the patient's teeth were wider mesiodistally. The Chu's bone sounding gauge was used to ensure biologic width was reestablished after the soft tissue incisions were placed to restore tooth dimensions. The establishment of an ideal contact position and interdental crestal bone has a symbiotic relationship to the supporting periodontium.[3] Another important aspect considered is the contact relation to the interdental bone, which helps to avoid black triangles and impingement of the biologic width which forms the basis of the biomimetic restoration. Since there are no ideal dimensions relative to crown length and width ratios, approximation studies have revealed that the tooth proportion ranges from 72% to 81%.[6] Hence, keeping in mind the above-mentioned concept and the preoperative smile analysis, a wax mock-up was made on the diagnostic cast.

The universal adhesive system used (SOLARE universal adhesive, GC India) had a superior bond strength to enamel compared to other adhesive systems. The palatal putty index method reduced the chairside time and aided in transferring exact tooth dimensions during the diastema closure.

The maxillary midline was established with reference to the facial midline and the maxillary philtrum, which is the most reliable landmark. Maxillary central incisors are usually the keystones for an ideal smile designing.[7] Preoperatively, the maxillary and mandibular midlines did not coincide having a preoperative midline shift of the lower arch towards the left.

The ideal treatment plan could have included orthodontic treatment to equalize the spaces and correct the midline followed by restorative and periodontal intervention. This was the first line of treatment suggested to the patient; however, the patient was not willing for the orthodontic treatment. Therefore, patient autonomy was followed according to ADA guideline (Section-1).[8] So a resto-perio intervention was planned to attain sustainable results within the limitations of the case.

The evidence from published literature states that discrepancies of dental midline up to 4 mm do not get perceived due to the reduced visibility and the uniform size of the lower anteriors and hence do not appear unaesthetic.[9] In this case, the diastema closure was carried out with reference only to the facial midline corresponding to the maxillary arch midline.[9],[10]

In conclusion, this case report suggests the use of the proposed classification as a template for a multidisciplinary treatment approach to achieve optimal function and aesthetic results in diastema closure. The Chu's proportion gauge with interchangeable tips represents an ideal and easy-to-use tool which provides a clear and objective communication between the different specialists.

Statement of clinical significance

A classification involving interdisciplinary approach for management of diastemas in situations, which do not demand an orthodontic intervention or when patient is not willing for orthodontic intervention, has been presented. To achieve ideal aesthetics, an interdisciplinary approach would be the best option for predictable results. Lack of a classification for management of diastemas in the literature led us to create a novel classification for its management, involving restorative and periodontal procedures. This can give an idea for decision-making in smile-designing procedures.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Abraham R, Kamath G. Midline diastema and its aetiology-a review. Dent Update 2014;41:457-64.  Back to cited text no. 1
Huang WJ, Creath CJ. The midline diastema: A review of its etiology and treatment. Pediatr Dent 1995;17:171-9.  Back to cited text no. 2
Schwartz JC. The metrics of anterior diastema closure. Dent Today. 2011 May;30(5) 112, 114-5. PMID: 21650124.  Back to cited text no. 3
Lee YK, Yu B, Lee SH, Cho MS, Lee CY, Lim HN. Shade compatibility of esthetic restorative materials-A review. Dent Mater 2010;26:1119-26.  Back to cited text no. 4
Chu SJ. A biometric approach to predictable treatment of clinical crown discrepancies. Pract Proced Aesthet Dent 2007;19:401-10.  Back to cited text no. 5
Ward DH. Proportional smile design: Using the recurring esthetic dental proportion to correlate the widths and lengths of the maxillary anterior teeth with the size of the face. Dent Clin North Am 2015;59:623-38.  Back to cited text no. 6
Davis NC. Smile design. Dent Clin N Am 2007;51:299-318.  Back to cited text no. 7
The ADA website. Available from: [Last accessed on 2020 Dec 07].  Back to cited text no. 8
Kokich VO Jr, Kiyak HA, Shapiro PA. Comparing the perception of dentists and lay people to altered dental esthetics. J Esthet Dent 1999;11:311-24.  Back to cited text no. 9
Bhuvaneswaran M. Principles of smile design. J Conserv Dent 2010;13:225-32.  Back to cited text no. 10
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Correspondence Address:
Dr. Arathi Ganesh
Professor and Head of the Department, Department of Conservative Dentistry and Endodontics, Faculty of Dental Sciences, Sri Ramachandra Institute of Higher Education and Research (DU), Chennai - 600 116, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijdr.IJDR_952_20

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]

  [Table 1], [Table 2], [Table 3], [Table 4]


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