Simple and cost-effective approach for maxillary bilateral posterior intrusion: Nandlal Toshniwal Rural Dental College double intrusion arch

INTRODUCTION

Supraerupted maxillary molars are a common clinical finding in dental practice. An early loss of any molar is bound to cause supra-eruption of opposing molar into that space. Overeruption of such molar can lead to occlusal interference, functional disturbances and cause great difficulty during prosthetic reconstruction, especially in adult patients.^[1] To reconstruct the proper occlusion for the posterior dentition and to maintain periodontal health, an interdisciplinary and comprehensive dental treatment is necessary. In this context, the orthodontic intrusion of the overerupted antagonistic tooth to facilitate prosthodontic rehabilitation is a desirable strategy.

Conventional orthodontic techniques for intrusion require anchorage reinforcement by incorporating multiple teeth, which depend heavily on patient cooperation and usually result in extrusion of other teeth rather than a molar intrusion. However, the task is formidable with routine orthodontic mechanics and control of anchorage is difficult.

In recent years, temporary anchorage device have allowed orthodontists to overcome these drawbacks while avoiding anesthetic full-appliance therapy.^[1-3] However, mini-implants and miniplates have certain disadvantages like higher cost, limited area for insertion, and the need for two separate insertion and removal surgeries,^[1] insufficient space on the buccal side to insert a mini-implant safely between the roots, especially in the region of the upper molars.^[4-5] To overcome these disadvantages, we designed a new intrusion appliance called Nandlal Toshniwal Rural Dental College (NTRDC) double intrusion appliance, where we intruded two molars of both sides simultaneously.

The present case report documents a case of an adult patient who requires prosthetic replacement of posterior teeth. As the roots of premolar and molar were so close, there was very less interdental bone to place the implant. Hence, it was an ideal case to use such appliance for the intrusion of posterior teeth where the other modern methods were difficult to apply.

CASE REPORT

A 37-year-old woman was seeking restoration of her right and left posterior occlusion. She presented with a full complement of teeth except for the mandibular right and left first and second molars that were extracted 3 years ago because of decay. As a result, the maxillary right and left first and second molars were overerupted and there was insufficient occlusal clearance [Figures 1 and 2]. Judging by the marginal ridge discrepancy, the maxillary first molar had overerupted 3-3.5 mm occlusally, encroaching upon the antagonistic missing dental space. The objective of the treatment was to intrude the overerupted molar utilizing NTRDC intrusion arch and subsequently regain the appropriate dental space for prosthesis.

Close

Figure 1

Pretreatment intraoral photographs. (a) Right buccal view. (b) Frontal view. (c) Left buccal view. (d) Upper occlusal view. (e) Lower occlusal view

Export to PPT

Close

Figure 2

Pretreatment panoramic radiograph

Export to PPT

Appliance construction and treatment outcome

1. A pair of the framework was fabricated on working model with 21 × 25 inch stainless steel wire, which was adapted along the contours of canine, premolars, and third molar buccally and continuing it palatally. This was done to reinforce the anchorage. Helices were incorporated in the framework high in the vestibule in line with first molar and second molar for the engagement of elastics [Figure 3].

   

   Close

   Figure 3

   Wire framework. (a) Right side, (b) Palatal side, (c) Left side

   Export to PPT

2. The prestretched elastic was engaged into the helices for applying light force [Figure 4].

   

   Close

   Figure 4

   Nandlal Toshniwal Rural Dental College double intrusion arch with elastic in place (a) Right buccal view, (b) Left buccal view, (c) Upper occlusal view

   Export to PPT

Expected intrusion of molar was achieved in the time frame of 2 and 1/2 months [Figures 5 and 6].

Close

Figure 5

Posttreatment intraoral photographs. (a) Right buccal view. (b) Frontal view. (c) Left buccal view. (d) Upper occlusal view. (e) Lower occlusal view

Export to PPT

Close

Figure 6

Posttreatment panoramic radiograph

Export to PPT

For retention purpose, at least till the prosthesis was delivered, a 19 × 25 inch stainless steel wire was adapted and bonded on the buccal surface of premolars and molars [Figure 7].

Close

Figure 7

Retainers in place (a) Right buccal view, (b) Frontal view, (c) Left buccal view

Export to PPT

DISCUSSION

The case exemplified an effective mechanism using a NTRDC double intrusion arch to intrude overerupted tooth in patients who seek restorative care. With the advent of double intrusion arch, the need for possible crown reduction as preprosthodontic modality can be eliminated. Furthermore, the current strategy largely avoided the placement of full strap up fixed orthodontic appliances. The set up did drastically reduce the financial burden on the patient as well. The orthodontic clinician may adopt this conservative and cost-effective strategy in their routine practice. Molar intrusion is a challenging task, and it is more so in adult patients with restorative concerns. Loss of the mandibular first molar often results in overeruption of the opposing teeth; resulting in occlusal interference, functional disturbances, compromised periodontal health, and increased complexity of restoring the edentulous space.^[2] Use of miniscrew implant in preprosthodontic management has drawn great interest in recent years among researchers and clinicians. However in this case, we could not use mini-implants because of less space between roots of premolars, and we don’t want patient to suffer an additional trauma of implant placement, so we designed the NTRDC double intrusion arch for this patient.

The intrusion of supererupted maxillary molars has been described by numerous authors, employing various treatment modalities with a wide range of movement rates and treatment times. Methods of correcting this problem generally involve either grinding the elongated tooth in preparation for a full-crown restoration or intruding the molar with an intermaxillary device,^[6] sectional mechanics,^[7] a removable appliance, a transpalatal bar,^[8]anchorage from mini-plates^[2] or mini-screws,^[3]or magnets.^[9] The present case was described as unique as there was very less interdental bone between premolars and molars limiting the use of modern methods like mini-implants for the molar intrusion. So, we designed NTRDC double intrusion arch. The elastics were used as it exerts the optimal amount of force required for intrusion (this kind of tooth movement requires light force).

In this report, we have demonstrated a simplified version of replacing mini-screws with NTRDC double intrusion arch to intrude the maxillary first and second molars simultaneously on both sides. Most importantly, the molar responded well to the intrusive forces throughout treatment, no root resorption was detected during follow-up, and the vitality of the teeth was sustained after 6 months follow-up. The orthodontic clinician may adopt this conservative and cost-effective strategy in their routine practice. The coordination of different specialties allowed us to gain optimal results in a shorter treatment time.

CONCLUSION

The present article serves as a viable alternative to carryout molar intrusion in such patient where today’s modern methods cannot be used, thus emphasizing the role of these appliances in orthodontics. The favorable result obtained shows that the intrusion procedure is an acceptable treatment option for extruded molars that can be preferred instead of prosthodontics reduction or the extraction of the extruded tooth.