Reconstructive surgery with chin block graft and esthetic rehabilitation of missing anterior tooth.

The complete and predictable restoration of the periodontium following infection or trauma remains a critical objective in regenerative therapy. Bone grafts remain among the most widely used therapeutic strategies for the correction of periodontal osseous defects. For periodontally compromised anterior teeth, reconstruction of the ridge along with natural tooth pontic serves both the purpose of regeneration and esthetics. The right lower central incisor of a 28-year-old male that was periodontally compromised was extracted. Autogenous chin grafting followed by retrograde surgery of the extracted tooth and replacement by natural tooth pontic was done. After 6 months, there was significant improvement in clinical picture and bone fill. This procedure provided excellent regenerative and esthetic results for the periodontally compromised lost anterior tooth.

INTRODUCTION

The ultimate goal in periodontal therapy is creation of an environment that is conducive to maintain the patient's dentition in health, comfort, and function. The shift in therapeutic concepts from resection to regeneration has significantly impacted the practice of periodontology in the last quarter of this century.[1] Autogenous bone graft harvested from the patient's own body has been considered ideal because of its osteoconductive, osteoinductive, and osteogenic properties.[2] For repair of most localized alveolar defects, block bone grafts from the symphysis and ramus buccal shelf are preferred.[3] Though bone grafting compensates for the bone loss, the anterior teeth affected with severe periodontitis are sometimes in unsalvageable condition.[4] Extraction of these teeth leads to esthetic, phonetic difficulties and functional disability. Replacing a missing tooth in esthetic zone in a single visit can be made possible with conservative bridge using natural tooth pontic.[5] The following case report describes a case of periodontally compromised tooth treated by natural tooth pontic preceded by bone augmentation with autogenous chin block graft.[3]

CASE REPORT

A 28-year-old male patient reported to the Department of Periodontics with the chief complaint of extruded and mobile mandibular right central incisor. Clinically, the patient presented with extrusion, grade III mobility, and grade II calculus. Intraoral periapical (IOPA) radiograph revealed poor bone support and associated root resorption. Because of poor prognosis, it was decided to extract 41 and to augment the residual ridge deficiency by autogenous block graft from chin, followed by natural tooth pontic. Replacement options for the resulting edentulous space were discussed with the patient and an informed consent was taken.

Methods

Thorough scaling and root planing was done. The diseased tooth was extracted carefully without causing any trauma to the tooth. One week time was given for the healing of gingiva. Then bone augmentation was done by harvesting the graft from the symphysis region [Figure 1a and b]. Before the surgery, patient was premedicated.

Figure 1

(a) Preoperative (1 week after extraction); (b) IOPA

Premedication included the following:

Dexamethasone 8 mg (Dexona; Zydus Cadila Healthcare Ltd, Ahmedabad, India) i.v. to reduce postoperative edema and stress during the procedure

Diclofenac sodium (Voveran; Novartis, Mumbai, India) 75 mg i.m. to alleviate pain during and after the procedure

Glycopyrrolate (Pyrolate; Neon Laboratories, Mumbai, India) 0.02 mg i.m. to reduce secretions

Diazepam (Calmpose; Ranbaxy Pharma, Gurgaon, India) 5 mg i.m. to allay anxiety.

The incision began in the sulcus from 35 o 45 t. A full-thickness mucoperiosteal flap was reflected to the inferior border, which resulted in a degloving of the anterior mandible and allowed for good visualization of the entire symphysis [Figure 2]. The graft size should be approximately 2 mm larger than the recipient site in horizontal and vertical dimensions to allow for contouring. A 702L tapered fissure bur in a straight handpiece was used to penetrate the symphysis cortex via a series of holes that outlined the graft. It is important not to encroach within 5 mm of the apices of the incisor and canine teeth and the mental neurovascular foramina. The inferior osteotomy was made no closer than 4 mm from the inferior border. All holes were connected to a depth of at least the full extent of the bur flutes (7 mm), and the graft was harvested using bone spreaders and straight and curved osteotomes [Figure 3]. The graft was placed in normal saline before contouring and fixation. The donor site was then packed with gauze soaked in saline. Closure of the site was performed with 3-0 sutures after recipient site closure [Figures 4–6]. An extraoral dressing was placed thereafter.[3]

Figure 2

Flap reflected

Figure 3

Donor site

Figure 4

Graft placed

Figure 6

Immediately postoperative IOPA

Suturing done

Suitable antibiotics and analgesics (amoxicillin 500 mg three times per day and ibuprofen 800 mg three times per day for 5 days) were prescribed, along with chlorhexidine gluconate rinses (0.2%) twice daily for 2 weeks. Patient was recalled after 10 days [Figure 7].

Figure 7

Postoperative (after 10 days)

Length of the natural tooth pontic needed was determined on a study cast of the patient using the incisal edge of adjacent central incisor and the location of gingival margin as reference points. This length was recorded.[6]

After 21 days, the access was opened, and the inside pulp chamber was cleaned of any pulp tissue and filled with protaper gutta-percha points and AH Plus sealer. The root of tooth was resected 2 mm below the cemento-enamel junction with a 556 bur (SS White Burs New Jersey, US) and retrograde filling was done. The gingival aspect of the tooth was smoothened and shaped to be rounded. A modified ridge lap shape was given to the cervical area to facilitate cleaning and appearance of emerging profile. The pontic was also cleaned with pumice, washed, and dried. Adjacent teeth were also cleaned with slurry of pumice and dried, and then acid etched with 35% phosphoric acid. Unfilled bonding agent (Margin Bond) was applied on them using micro brush and light cured for 20 s using light-curing LED unit. At the same time, the pontic tooth was immersed in 37% phosphoric acid for 30 s, washed, dried, and unfilled bonding agent was applied and light cured using LED light-curing unit for 20 s from all the four aspects (mesial, distal, buccal and lingual).[6]

A pre-impregnated fiber was cut for connecting the pontic tooth to adjacent teeth. To measure the length of the fiber needed, a piece of dental floss was placed on the facial surfaces of the teeth, extending from the left mandibular lateral incisor to the right mandibular lateral incisor. The pontic was positioned carefully and a drop of flowable composite was placed on the mesial and distal aspects of pontic to stabilize its position correctly and prevent any movement during placement of the fiber. After positioning the fiber on pontic and adjacent teeth, the composite was placed over the fiber and light cured for 40 s.[6]

The patient was instructed to clean under pontic and the gingival embrasure areas between the teeth using superfloss. Using a proximal brush to clean the embrasure areas was demonstrated to the patient.[6]

RESULTS

Patient was kept on a regular follow-up. Soft and hard tissue evaluation was done at 1, 3, and 6 months from the baseline. It was noticed that the clinical picture improved considerably [Figure 8]. Postoperative radiographs were taken which showed good bone fill in the osseous defect [Figure 9a and b].

Figure 8

Natural tooth pontic

Figure 9

(a) IOPA (after 2 months); (b) IOPA (after 6 months)

DISCUSSION

The presence of an adequate recipient site is one of the most important prerequisites for any procedure. Therefore, reconstruction of alveolar ridge deficiencies should be done before proceeding for prosthetic options. The preferred material during a reconstructive procedure is autogenous bone, as it carries proteins such as bone-enhancing substrates, minerals, and vital bone cells. Other bone grafts such as allografts or xenografts carry no vital cells and have been shown to be unpredictable in terms of the amount of osteogenic promoters present.[7] Sites used for harvesting autogenous bone for alveolar reconstruction have been demonstrated in both extraoral and intraoral locations. Extraoral harvesting sites include the posterior iliac crest of the hip and the calvaria.[8] Extraoral sites allow ample bone to be harvested; however, these sites involve complex surgical procedures that increase the operative and anesthesia time and are associated with increased morbidity at donor sites. In comparison, intraoral sites have the advantage of being in close proximity to the recipient site, decreased healing periods, and decreased morbidity. Common intraoral sites include the maxillary tuberosity, tori exostosis, and the ramus and symphysis of the mandible. The mandibular symphysis has two important advantages over the other intraoral sites: (1) topographic accessibility and (2) significant volume of cancellous and cortical bone for harvesting. Concerns with this type of procedure are possible altered facial contour, postoperative sensory disturbances, and prolapsed symphysis muscles (“chin droop”).[9]

Replacement options for a single missing tooth include conventional fixed partial dentures, a removable partial denture, and a single tooth implant. A resin-bonded fixed partial denture allows for more conservative tooth preparation. Dental implants in the esthetic zone are well documented in the literature, and numerous controlled clinical trials have documented satisfactory overall implant survival and success rates. Such restorations are sometimes complicated by the cost of the restoration and anatomical limitations. The development of adhesive systems has provided other treatment options with minimally invasive preparations and are often simpler.[10]

Natural Tooth Pontic procedure offers some advantages like good esthetic results, preservation of natural crown structure, requirement of no laboratory work, and reduced psychological impact on the patient. This technique is reversible and allows other restorative options to be evaluated; micro-resiliency of pontic allows stimulation of underlying tissue and avoids excessive post-extraction ridge resorption. Though replacing a missing anterior tooth with NTP is a simple, economical, and quick procedure, still it is an interim restoration and may not be used as a long-term permanent treatment method. The important factors to be considered before performing such restorations are: Patient's occlusion, parafunctional habits, space for composite resin bonding, primary dentition, and high esthetic expectations of patient.[10]

CONCLUSION

Patient's positive psychological response, cost effectiveness, and achievement of excellent soft tissue contours following autogenous bone graft placement have made this technique very useful. Natural teeth serve as an excellent, yet interim treatment option for immediate replacement following extraction in the anterior esthetic zone. The patient satisfaction of preserving his natural teeth in the post-extraction period, taking care of his esthetic needs, and simultaneously providing him with time to choose from the various final treatment options available is immense. Moreover, block bone grafts from the symphysis offer advantages such as close proximity of donor and recipient sites, convenient surgical access, decreased donor site morbidity, and decreased cost. Appropriate patient selection, their motivation levels, plaque control, and precision during placement should be kept in mind to achieve the desired objective.