Multidisciplinary treatment approach in severe Molar Incisor Hypomineralization: - A Case Report

The term Molar Incisor Hypomineralization (MIH) was introduced first in 2001, defined as development enamel disorder characterized by hypomineralization of systemic origin of first permanent molars, often associated with permanent incisors.1 MIH, also referred to as "hypo mineralized” PFMs2, "idiopathic enamel hypomineralization, "3,4 “demineralized” PFMs,5

"nonfluoride hypomineralization, "6,7and "cheese molars, "8.9 the disturbed function of ameloblast cells causes all these conditions during the transitional and maturational stages of amelogenesis. 3,10

Clinically, the hypomineralization can be seen as an abnormality in the translucency of enamel (opacity), which can be of different colors depending upon the severity of MIH and often undergo post-eruptive enamel breakdown due to soft and porous enamel.11 The etiology is multifactorial, which includes neonatal problems, sickness during early childhood, or medically compromised children.12,13,14,15,16,17,18 The treatment approach of MIH consists of early diagnosis, caries risk management, remineralization therapy for prevention of decay and caries, restorations.19,20 Depending upon the occasion, molar restoration could be composite restoration, metal inlays, and crowns, whereas anterior teeth are restored using veneers or esthetic fillings.20

This case report presents the multidisciplinary approach to a patient with MIH on borderline skeletal class III malocclusion to achieve satisfactory esthetics and prevent further trauma to upper teeth.

Case report

A 16-year-old male reported with a chief complaint of irregularly placed lower front teeth and the inability to utilize the front teeth to bite correctly with no relevant associated medical history. There was a history of root canal treatment in 11 & 21. Clinical frontal examination revealed a comparatively symmetrical face with mesomorphic facial form, no incisal display at rest. (Fig 1) Clinical profile examination revealed a straight profile with anterior facial divergence, normally positioned chin, acute nasolabial angle, retrognathic maxilla, orthognathic mandible with retrusive lower lips, low mandibular plane angle (Fig 1). Intra-oral examination revealed good oral health with apparently symmetrical arches, multiple rotations. The inter-arch relationship showed a reverse overjet of 0.5mm and overbite of 9 mm each. Class I molar and canine relationship existed in maximum intercuspation on both sides. The mandibular midline was shifted to left by 1.5 mm. There was severe attrition in anterior maxillary teeth (Fig 1).

Functional examination revealed no tenderness of temporomandibular joint, the patient was an oronasal breather, with normal mastication and deglutition and mouth opening within a healthy range. Cephalometric examination revealed a Skeletal Class III skeletal pattern with the retrognathic maxilla and orthognathic mandible with horizontal growth pattern, maxillary incisors were proclined, and mandibular incisors were upright. Soft tissue profile showed an acute nasolabial angle, deep mentolabial sulcus, retruded lower lip (Fig 2). The Orthopantomogram revealed no temporomandibular irregularities/ pathology, unerupted third molars. The crown-root ratios were normal, with good alveolar bone levels (Fig 2).

Fig 1: Pretreatment photographs

Fig 2: Pretreatment x rays: Lateral Cephalogram and Orthopantomogram

PROBLEM LIST AND TREATMENT OBJECTIVES

Problem list Included Reverse smile arc, Skeletal Class III jaw bases, and supra erupted lower anterior teeth, attrition of upper incisors, anterior crossbite, overclosure of the mandible, the increased curve of Spee. Revised treatment objectives were set after the patient refused to underwent Orthognathic surgery. These included restoration of smile arc to consonant form, the intrusion of lower incisors to correct deep bite and to level curve of Spee

TREATMENT PROGRESS

The patient was explained about treatment limitations and started with fixed orthodontic braces in the lower arch first. Preadjusted Edgewise bracket system 022” X 028” was used. One lower incisor (31) was extracted due to tooth size arch length discrepancy. Remaining lower incisors were intruded with archwire (Fig 3, 4). After leveling and alignment of the lower arch, the Upper arch was started.

Figure 3 intraoral photographs with treatment progress

Figure 4: Mid-stage radiographs

After the intrusion of upper and lower incisors, upper incisors were prepared for crown placements, and temporary crowns were given according to Subharti Protocol 21. Treatment was further continued

and finished with temporary crowns over 11 and 21 (Fig 5, 6). At the end of treatment, we were able o achieve Consonant Smile Curve, satisfactory overjet, overbite and good interdigitations (Fig 7,8,9)

Figure 5 intraoral photographs with treatment progress

Figure 6: Mid-stage radiographs

Figure 7. Intraoral photographs showing treatment progress

Figure 8: Post-treatment extraoral photographs

Figure 9: Post-treatment intraoral photographs

Fig 10: Post-treatment x rays: Lateral Cephalogram and Orthopantomogram

Discussion: - Treatment approaches of MIH consists of early diagnosis; caries risk management, remineralization therapy for prevention of decay and caries, restorations 19,20. Teeth beyond restoration need extraction and space closure by orthodontic means. The case in our case report was very challenging due to the amount of severe attrition and reverse overjet and reverses deep bite along with skeletal Class III jaw discrepancy. An ideal treatment plan was a mandibular surgical setback, which was refused by the patient. The next option (Single mandibular incisor extraction) was a viable alternative, keeping in mind the severity of negative overjet and deep bite. We were able to intrude lower incisors below the occlusal plane and able to give positive overjet, which was the primary objective concerned to smile aesthetics of the patient. Later on, the upper incisor position was finalized by temporary crowns as a significant amount of tooth structure was lost due to attrition21. Temporary crowns acted as a guide for final vertical positioning and intended inclination of upper incisors. Upper incisors were monitored through the treatment as they were RCT Treated, and there could be increased root resorption increased in these teeth.

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