Immediate Oral Rehabilitation Using Dental Implants After Marginal Mandibulectomy: A Case Report

The presence of odontogenic tumors, such as ameloblastoma, can result in clinical situations where patients require mandibulectomy, which causes a loss of teeth and mandibular bone.^1,2  Mandibular reconstruction techniques are always a challenge to oral and maxillofacial (OMF) surgeons^1,3,4  because they involve multiple interventions, financial costs, social ramifications, and long treatment periods, which often create difficulties with rehabilitation.

Techniques and treatment plans required for OMF rehabilitation should be available.^3,5  Technological advancements have enabled more rapid, safer, and more secure treatments than in the past.^6,7  Health professionals should work with these technologies to improve the quality of life of their patients.⁸  The use of short and narrow osseointegrated implants (OIs) is currently considered to be secure and useful^9,10  even in treating atrophic mandibles.¹¹  The mandibular reconstruction plates are used to maintain the shape of the face in patients who require mandibulectomy¹  and those with atrophic mandible bone¹¹  associated with osseointegrated implants with good success rates.

This article aims to describe a case using an unusual approach where the patient had an oral rehabilitation that was secure, fast, predictable, stable, functional, esthetic, and had psychological benefits. The patient was treated with marginal mandibulectomy and immediate rehabilitation with OIs; a hybrid prosthesis was fabricated a short time thereafter.

A 32-year-old woman was referred by her general dentist with chief complaints of swelling in the gingiva in the anterior part of the mandible, which began approximately 30 days previously. A clinical examination did not reveal any extraoral abnormalities. However, intraoral examination revealed a nonspecific growth between teeth 26 and 27. The mucosa was normal and the teeth were separated from one another (Figure 1).

Conventional radiography and cone beam computed tomography revealed radiolucent areas, undefined contours, and a multilocular aspect extending from elements 21 to 29. There was some suggestion of intact bone along the mandibular base (Figure 2). An incisional biopsy was performed (Figure 3) in different areas of the lesion, and specimens were sent for anatomopathological examination. Microscopic analysis revealed desmoplastic ameloblastoma (Figure 4).

The treatment plan consisted of a multidisciplinary approach, while rehabilitation always involved questions and discussion. All plans and alternatives were discussed with the patient, including limitations and the possibility of complications.

The treatment plan selected was marginal mandibulectomy and, on the same day, placement of osseointegrated implants (OIs) with immediate loading. Impressions of the dental implants were performed on the same day. A hybrid prosthesis for oral rehabilitation was scheduled to be fabricated a short time thereafter.

Impressions of each arch were taken, and the casts were mounted on a semi-adjustable articulator. A multifunctional acrylic guide was constructed, extending between teeth 30 and 21. The guide was fabricated by taking into account the position of the teeth present; a prosthetic wax-up was unnecessary because her teeth were present.

With one three-dimensional model of the mandible, a reconstruction plate with a 2.4 mm system (2.4 mm Neoface System, Neortho, Curitiba, Brazil) was pre-bent (Figure 5). It was extended from the right to the left angle of the mandible along the base. The same three-dimensional model was used to plan the marginal mandibulectomy (Figure 5).

The patient was moved to the operating room to undergo surgery under general anesthesia. After the buccal and lingual flaps were performed the pre-bent reconstruction plate was placed and the screw holes were completed. A reciprocating saw and cylinder burs were used to perform marginal osteotomy and remove the lesion. Using pear burs, an abrasion was performed in critical areas of the remaining mandibular bone (Figure 6).

The screws were positioned in specific predemarcated areas so that screws did not prevent the OIs from being placed. The posterior screws were placed with transcutaneous access with use of a trocar instrument.

After the plate and screws were positioned, a multifunctional acrylic guide was used, and five Morse taper OIs (Neodent, Curitiba, Brazil) were placed in the remaining mandibular bone (Figure 6), three of which were 3.5 mm × 7 mm, and were placed in the anterior area of the mandible. These crossed in the mandible base. The OI situated in the area of 21 was 3.5 mm × 8 mm and, the OI positioned in area 30 was 3.5 mm × 9 mm. All of them had > 45 N of primary stability. The multiunit abutments and cylinders were placed. Sutures were completed using Vicryl 4-0 thereafter (Ethicon, Bridgewater, NJ; Figure 7).

On the same day, after the patient had recuperated, impressions and occlusal registrations were performed in the hospital office. The patient stayed at the hospital. After 24 hours, the prosthetic wax-up of the primary teeth was tested. The patient approved and consented to finish the prosthesis.

Forty-eight hours after surgery, the hybrid acrylic-metal prosthesis with 11 inferior teeth was placed in the patient (Figure 8), who experienced minimal swelling and discomfort (Figures 9 and 10), was oriented and conscious, and was discharged home with antibiotic and analgesic drugs.

On follow-up 15 days later, the patient underwent occlusal adjustments and the external sutures from the transcutaneous access were removed. The patient is followed-up every 6 months. Once per year, her prosthesis is removed for cleaning and adjustments are made, if necessary (Figure 11). Imaging examinations are also performed every 6 months (Figure 12).

One year postoperatively, the OI from area 23 was lost. The area 23 cylinder of the prosthesis was filled with composite resin. She still has the same prosthesis 6 years after treatment (Figure 13), with functional and esthetic satisfaction (Figure 14).

In 2018, it was estimated that 51 540 individuals in the United States were affected by lesions in the face and oral cavity.¹²  The mutilations resulting from surgical treatment for tumor resection are significant. These patients will require years of rehabilitation, with some requiring rehabilitation for the remainder of their lives.^3,13,14  Aside from financial costs, the social and psychological ramifications are often uncalculated.¹⁵  The families are broken, children are unadvised, and the patients can acquire other diseases including depression.^13,14  Therefore, rehabilitation should always be carefully considered, including its anticipated duration and course.

Mandibular reconstructions are always a challenge. Most patients will require several complex surgeries, and rehabilitation is concluded only after a long period of treatment.^3,5  When primary reconstruction can be performed, a waiting period for integration of bone graft(s) is required, after which patients will have OIs placed.¹⁶  This time implies almost 1 year of treatment and at least 3 or 4 surgeries. When indications for secondary reconstruction arise, the period of treatment and the number of surgeries increase.^1,3 

Primary bone reconstruction and dental implants can sometimes be indicated in the same surgery.¹⁷  Other authors believe that primary reconstruction can have biologic interfering with osseointegration are not very good, and they are contraindicated.¹⁸  One problem encountered is the unfavorable position of an OI. This can occur when surgeons try to place implants together with mandibular reconstruction without references to occlusion and teeth.^11,19  Today virtual surgical planning has become better in treatment plans, but still there are some deficiencies.^20,21 

However, we demonstrate here an alternative to large mandible reconstruction. Some residual bone is necessary for this treatment.¹¹  Currently, this technique appears to be well accepted.^22,23  Its indication will depend of the evolution of the lesion(s). In this case, we could see one short, but sufficient, remaining bone in the base of the mandible. In most cases, this small bone cannot be preserved. Consequently, a different treatment plan will be necessary and may require reconstruction and longer rehabilitation.^2,3 

The use of short and narrow implants has increased in the past decade.^9,10  Many studies have demonstrated their efficiency and safety in rehabilitation, even in total atrophic mandibles,^11,24  as in this case. The patient in this case has had 6 years of follow up with the same prosthesis after surgery. She visits the office every 6 months for cleaning and regular examinations. However, she lost an OI 1 year postoperatively, in the region of 23, and lost bone around the implant situated in area 30.

We considered that both areas experienced more trauma during the surgery. This could have been the cause, with the increase in temperature of the bone leading to bone loss around those implants (ie, teeth 30 and 23). In the area of 23, we performed a strong abrasion using a pear bur because we believed this area had more extension of the lesion to the basal bone. The 30 region was local, near the reciprocating saw cut; consequently, this could have influenced bone reabsorption around the implant.

Another plausible explanation is varying mandibular flexibility.²⁵  There are different flexibilities between the anterior and posterior parts of the mandible. As such, some authors have recommended that a dental bridge should not be kept attached near the anterior and posterior implants.^25,26  A total bridge, fixed in one piece, involving anterior and posterior dental implants should be avoided because of this different flexibility.^25,26  This can lead to more bone loss in the posterior OI. However, some investigators do not believe this is relevant.²⁷  We do not usually prefer to fabricate a total one-piece fixed prosthesis in the inferior arch involving posterior and anterior dental implants. We talked with the patient and, when the implant is completely lost, we have a plan to place another OI more anteriorly and leave the other tooth (ie, number 30) in cantilever. We have not done this yet because the dental implant in the region of 30 continues be stable and without inflammation. When this implant is replaced, a new prosthesis will also be placed.

The design of the patient's prosthesis was similar to that found in most patients with total inferior edentulism, known as Branemark Protocol 1.²⁷  Of course, in this case, it is larger than in regular patients. However, most oral rehabilitations after mandibular reconstruction require large prostheses.²  The difference is these prostheses are made after multiple surgeries to recover soft and bone tissue. It is important to be aware that this prosthesis is difficult to clean but is functionally and esthetically adequate.

This case illustrated a nontypical approach, which resulted in a secure, fast, predictable, stable, functional, and esthetic outcome, with psychological benefits. We performed two surgical procedures, one for the incisional biopsy, and other to remove the lesion and place the OI. Careful examinations were performed to address minor interventions and social ramifications. Treatment plans need to be openly discussed with patients, even the possibility of other surgeries, as we had done with this patient.

Nevertheless, this treatment plan demonstrated its utility and efficiency in this case. An approach with fewer surgeries and OMF rehabilitation needs be considered in all cases.

Abbreviations

OI:

osseointegrated implant

OMF:

oral maxillofacial

The authors declare no conflicts of interest.