Full mouth rehabilitation with zygomatic implants in patients with generalized aggressive periodontitis: 2 year follow-up of two cases.

Rehabilitation of severely atrophied maxillae is often a challenge and patients with generalized aggressive periodontitis (GAP) make it even more complicated. This clinical report describes rehabilitation of GAP patients with zygomatic implants and followed-up for 2 years. Two patients of age 33 and 44 reported to a private dental practice and were diagnosed with GAP. Various treatment options were considered after which it was decided to do a full mouth implant supported fixed rehabilitation, with a combination of conventional and zygomatic implants. Two zygomatic and four conventional implants were placed and immediately loaded with a provisional prosthesis. After 6 months, definitive prosthesis was delivered. Implants and prostheses were followed-up for 2 years. No implant failures occurred, but a few biological complications were observed. The most common clinical observation in these patients during recall visits was peri-implant soft-tissue inflammation, which is a biological complication. This was with no trouble, controlled by using proper oral hygiene aids and maintenance. Within the limitations of this study, we can state that it can definitely be considered as a viable treatment option treating patients with GAP. However, studies with more follow-up time and controlled clinical trials should be performed in order to document the longevity of this treatment modality.

INTRODUCTION

Aggressive periodontitis as defined by the international workshop for classification of periodontal diseases and conditions is “a multifactorial, severe and rapidly progressive form of periodontitis, which primarily but not exclusively affects young individuals.[1] It exhibits in two different ways, localized and generalized. Generalized aggressive periodontitis (GAP) is an uncommon form of periodontitis that affects at least three permanent teeth other than molars and incisors exhibiting episodic destruction of alveolar bone and attachment loss.[2] According to Lang et al. in 1999 aggressive periodontitis can be characterized by some unique features such as rapid attachment and bone loss, familial aggregation and except periodontitis patients will be otherwise clinically healthy.[3] This condition occurs in early age and these individuals express relatively increased immunologic and genetic risk factors for inadequate host response for periodontal pathogens.[4] Treatment for these patients will usually begin with reducing the pathogens by supportive periodontal treatments such as deep scaling, root planning and flap surgeries if needed. Combined mechanical therapy with a systemic dosage of antibiotics will be more effective. However, most treatment plans include a strategy to facilitate oral hygiene by means of extracting teeth with hopeless prognosis and restoring by provisional restorations that can be easily cleaned and maintained by the patients.[5] Dental implants have become an integral part of prosthetic rehabilitation. Implant therapy for periodontally compromised patients has been documented by various studies,[67] Schou has performed a review on “Outcome of implant therapy in patients with pervious tooth loss due to periodontitis” in which human studies carried out from 1986 to 2006 were reviewed. This review concluded that the survival rate of implants and suprastructures of individuals with periodontitis was not significantly different than individuals who did not have periodontitis prior to tooth loss. Conventional implants have been used for prosthetic reconstruction of GAP patients. However, there are many times where there is not much bone left for conventional implant placement. Obviously with the GAP patients, bone loss is the key feature, which makes conventional implant placement a little complicated. In those patients, zygomatic implants can be used as a great alternative. Zygomatic Implants have been introduced as an alternative to conventional grafting and rehabilitation of severely resorbed maxilla.[8] High success rates and longevity have been documented with zygomatic implants,[89] zygomatic implants have been used along with conventional implants in full mouth rehabilitation, but there are not much details available in treating GAP patients with zygoma implants. This clinical report describes rehabilitation of GAP patients with zygomatic implants and followed-up for 2 years.

CASE REPORTS

Two patients of age 33 and 44 reported to a private dental practice with a chief complaint of loose teeth. On intraoral examination, following teeth were present in patients.

Case 1: 18, 17, 16, 15, 14, 13, 23, 24, 25, 26, 27, 28, 33, 34, 35, 36, 37, 38, 42, 43, 44, 45, 46, 47.

Case 2: 11, 12, 13, 14, 17, 18, 21, 22, 23, 28, 41, 42, 43, 44, 45, 48, 31, 32, 33, 34, 35, 38.

All teeth showed severe attachment loss and Grade III mobility. Both of them did not have any underlying systemic diseases. Patients did not have a history of any habits like smoking or pan chewing. Radiographic examination revealed severe bone loss of all existing teeth up to middle third of the root [Figure 1]. According to the predetermined criteria of at least three permanent teeth other than molars and incisors were involved with severe attachment loss and bone loss in the proximal region.[1] Pertaining to Armitage classification these patients were otherwise healthy, both had family history of early tooth loss and were having severe attachment and bone loss. After a systematic assessment by a Periodontist, these cases were diagnosed as GAP.

Figure 1

Pre-operative orthopantomogram

After a thorough examination and meticulous investigation, the Periodontist decided that the existing teeth have a bad prognosis and they were not salvageable. Despite that, an attempt was made to save these teeth. Initial antibiotic therapy with deep scaling did not show any improvement in the periodontal status of patients. Splinting was not considered, as all the teeth had Grade III mobility, which will not enhance the function or stability if connected together. After a thorough analysis, a decision was made to proceed to complete extraction followed by prosthetic restoration for the missing teeth. Various treatment options post complete extraction were discussed with patient: Total extraction followed by fabrication of conventional complete dentures; total extraction followed by bone grafting with delayed placement and loading of conventional implants for fully fixed prosthesis; placement of four conventional implants in the anterior maxilla followed by bar retained implant supported over denture. Patients were explained in detail about dental implants, their risks, complications of implants and their longevity and success. Patient expressed a desire for implant a fully fixed solution for both the arches. Considering the lack of adequate bone volume in the posterior maxilla, consolidation time after grafting procedure, patient's age and desire for immediate fixed prosthesis, the option of placing four conventional and two zygomatic implants with immediate loading principle was suggested to patient. Mandibular prosthesis was planned with four implant supported fixed partial denture. Patient agreed for the procedure after thoroughly understanding the risks, complications, survival and success of conventional and zygomatic implants.

Evaluation with a pre-operative panoramic radiograph and a computed tomography scan was used to plan the surgery. Maxillary and mandibular impressions were made. Diagnostic casts were mounted in semi-adjustable articulator using facebow transfer and interocclusal records. Since the occlusal vertical dimension, harmony and esthetics of the existing dentition were satisfactory, it was planned to use the existing teeth position as a guide for the fabrication of surgical guide. Teeth were knocked out at the cervical level to aid in the arrangement of artificial teeth. The completed teeth arrangement was duplicated in clear acrylic as a surgical guide. Openings were made on the cingulum of anterior teeth and occlusal surface of posteriors to identify osteotomy points during the surgery. In order to reduce the posterior cantilever of implant supported fixed prosthesis, osteotomy sites for zygomatic implant were planned as posterior as possible.

Under nasotracheal intubation general anesthesia was administered. Nearly, 2% of lignocaine with adrenaline was infiltrated into the right and left vestibules. The remaining maxillary teeth were extracted. Crestal, anterior and posterior vestibular releasing incisions were made and mucoperiosteal flap was elevated to expose the alveolar crest, the lateral wall of the maxillary sinus and the inferior rim of the zygomatic arch. A retractor was used to ensure good visibility of the zygomatic bone. Surgical guide was placed to identify prosthetically favorable position for the conventional and zygomatic implants. Maxillary bone was prepared to gain access to the inferior edge of zygoma. During the sequential osteotomy preparation, the thumb of the surgeon was positioned at the external surface of the upper edge of the zygoma to feel the preparation of the external cortical bone. Two zygomatic implants (Branemark System Zygoma TiUnite Implants; Nobel Biocare AB) [Figure 2] were placed using standard protocol after the assessment of length with a depth indicator. Implant emergence was at the junction of second premolar and first molar. An insertion torque more than 45 Ncm was achieved during the placement. Subsequently, four 4.3 × 13 implants (Nobel replace Tapered RP; Nobel Biocare AB) were placed in the right and left maxillary canine region following the standard osteotomy protocol [Figure 3].

Figure 2

Zygomatic implant (Branemark)

Figure 3

Surgical placement of conventional and zygomatic implants

Multi-unit abutments were connected to the anterior conventional implants (Multi-unit Abutment Nobel Replace RP; Nobel Biocare AB) and zygomatic implants (Branemark System Zygoma Multiunit abutments RP; Nobel Biocare AB). They were tightened according to the recommended torque values by the manufacturer [Figures 4 and 5]. The surgical wound was closed and sutured.

Figure 4

Post-operative orthopantomogram case 1

Figure 5

Post-operative orthopantomogram case 2

Since all the implants were showing adequate primary stability (above 40 Ncm) it was decided to load the implants immediately. Open tray impression copings were connected to multiunit abutments and rubber dam was placed. They were splinted with low shrinkage auto polymerizing acrylic resin (Pattern Resin, GC India). The segments between the copings were sectioned and then united with a small amount of resin to minimize the polymerization shrinkage. Open tray impressions were made with putty and light body consistency addition silicone impression material. Master casts were obtained and screw retained occlusal rims were prepared on this casts. Maxillo-mandibular relations were recorded and try-in was verified. A metal framework was used to reinforce the acrylic provisional prosthesis. After 48 hours of surgery, completed provisional prosthesis was connected with 15 Ncm torque. 6 months after placement, provisional prosthesis was replaced by definitive prosthesis [Figure 6]. Both patients were instructed to maintain the soft diet for 2-3 months period and they were reviewed periodically up to 2 years [Figures 7 and 8]. Follow-up visits were more frequent in the early stages of loading, i.e., 2, 4 and 6 months and every 6 months after that time period. Oral hygiene measures were reinforced and their hygiene status was evaluated at every recall visit. follow-up procedures performed during the recall visits included modified bleeding index, clinical mobility, suppuration and the mucosal seal efficacy evaluation.[10] The modified bleeding index was assessed by inserting a periodontal probe 1 mm into the sulcus, around the implant/abutment and values were recorded in an ordinal scale between 0 and 3 (0: No bleeding visible; 1: Isolated bleeding spot visible; 2: The blood formed a confluent red line on the margin; and 3: Heavy or profuse bleeding). Patients described in this case report had a modified bleeding index of 2. Mobility of implants was evaluated using manual movement to assess individual implant and registered as present or absent. Suppuration was evaluated by applying finger pressure to the peri-implant complex and registered as present or absent and mucosal seal efficacy evaluation, modified from the regular probing depth for standard implants (usually up to 4 mm in depth) and performed with a calibrated plastic periodontal probe, which recorded the space between the implant and the mucosa in millimeters. This modification was made as the implant was placed in the palatal, mesial and distal aspects of the maxillary bone, with no buccal support and therefore, the traditional criteria did not apply. The radiological evaluation was made with panoramic radiographs, but no bone height could be recorded as the implant platform slightly superimposed the marginal bone. An implant was classified as surviving, if it has fulfilled its purported function as support for the prosthesis, was stable when individually and manually tested, no signs of infection, a good esthetic outcome of the rehabilitation should be demonstrated.

Figure 6

Definitive prosthesis delivered 6 months after surgery

Figure 7

Radiographic evaluation after 2 years of function case 1

Figure 8

Radiographic evaluation after 2 years of function case 2

DISCUSSION

Studies have shown that dental implants show promising success rate in patients with periodontal diseases.[11] Usually, treatment procedures for these patients start with evaluation of existing dentition, periodontal treatment combined with antibiotic therapy. Furthermore, teeth that are not salvageable and cannot be treated will be extracted and followed by rehabilitation. Even with complete extraction, the pathogens associated with GAP will not be totally eliminated. In addition to the altered microbial flora, patients’ systemic response which is also compromised will also contribute much to the peri-implant infection. The most common complication with GAP patients is peri-implantitis, which can be associated with the microbial strains associated with GAP. Implant maintenance is more critical in these patients. However, it has been documented that patients in general with periodontal conditions can be treated with dental implants and the success rate is comparable with the normal patients with proper maintenance. A critical review of dental implant prognosis in periodontally compromised partially edentulous spaces was performed by Karaussis in articles that were published until 2006. This study shows that there was no statistically significant differences in both short-term and long-term implant survival exist between patients with a history of chronic periodontitis and periodontally healthy individuals.[7] GAP patients have also been successfully treated with implants and also is no evidence that GAP is a risk factor or contraindication for dental implant therapy.[1213]

In both cases reported in this article, patients were advised complete extraction followed by full mouth rehabilitation. Several removable and fixed treatment options were considered after, which full mouth fixed implant prosthesis was decided to be the treatment of choice. As bone loss was one of the main concerns with these patients, Zygomatic implants were used for rehabilitation. The advantage of using Zygomatic implants was that patients did not have to go through grafting procedure, which eliminated an additional surgical procedure and also shortened the treatment completion time. Furthermore, implants were evaluated continuously during the follow-up period. At the end of 2 years, no implant failure occurred. Standard diagnostic criteria were used for the assessment of implant failures, which included clinical signs of infection, clinical mobility and radiographic signs of failure.[14] However, a few clinical complications were observed. The following complication parameters were assessed: Fracture or loosening of mechanical and prosthetic components (mechanical complications); soft-tissue inflammation, fistula formation, pain or maxillary sinus infections (biological complications); esthetic complaints of patient or dentist (esthetic complications); phonetic complaints, masticatory complaints, comfort complaints or hygienic complaints (functional complications).[10] The most common clinical observation in these patients during recall visits was peri-implant soft-tissue inflammation which was, considered as a biological complication. This was with no trouble, controlled by using proper oral hygiene aids and maintenance. The success, failure and complication assessment on the implants placed in the mandible were not explained in detail, as this case report is to explain the rehabilitation of atrophic maxilla using zygomatic implants. Nevertheless, similar occurrences with no failure and very few biological complications were observed in the conventional implant placed in the mandible, during this period of time.

CONCLUSION

In our case series, which included two cases with 2-year follow-up, no implant failures occurred, the most common clinical observation in these patients during recall visits was peri-implant soft-tissue inflammation which was, considered as a biological complication. With bilateral sinus grafting, implant placement can be planned only after 6 months. Loading these implants might take an additional 4-6 months depending on the stability of the implants, which brings the time from extraction to getting fixed teeth to almost a year or more. Furthermore, sinus lift and grafting has its own risks and complications, which further delays the procedure. Treating these patients with zygomatic implants essentially helped patients to avoid extensive sinus grafting and reduced the treatment completion time. For a treatment option of bilateral sinus graft and conventional implant placement was to be performed, patient would have gone through intense bone grafting procedure (iliac graft and artificial bone graft material). After a healing time of 8 months, bone has to be evaluated and then implants will be placed. Implants placed in grafted sites are not suitable for immediate loading. Prosthesis will be placed on these implants 6-8 months after placement. This treatment option of placing Zygoma implants reduced the surgical phase and aided in getting fixed implant prosthesis much faster than a conventional implant placement procedure. This procedure requires thorough knowledge of the technique, superior surgical skills and meticulous training in prosthetic rehabilitation. Within the limitations of this study, we can state that it can definitely be considered as a viable treatment option treating patients with GAP. However, studies with more follow-up time and controlled clinical trials should be done in order to document the longevity of this treatment modality.