Lack of equilibrium between opposite arches in edentulous patient leads sometimes to major problems related to occlusal planes. They can be left untreated or improperly treated. This article reviews one such problem known as Combination Syndrome. The treatment method described involves using a fixed mandibular prosthesis over implants that have been placed immediately after extraction.
Rewarding outcomes depend on thorough evaluation and proper diagnosis of a patient’s oral condition. Once the starting point has been determined and the final outcome is designed, the treatment plan merely becomes the method of reaching the desired result.
Kelly first described combination Syndrome in 1972 as destructive changes in hard and soft tissues of patients with complete maxillary denture opposing an unstable bilateral free-end mandibular partial denture.1, 2 In different words, Combination Syndrome is a description of a dental condition that is the result of long term use of a few, usually (6) remaining lower anterior teeth, #22-27 and a complete upper denture with no other natural remaining teeth and a lower free end Kennedy class I removable partial denture. The normal biting pressure or forces are directed from the remaining lowfrocks teeth and transmitted through the upper anterior denture, with resulting resorption of bone and slow auto-rotation & tilting of the denture upward and backward, with the upper anterior teeth becoming less visible and the upper posterior teeth becoming more visible as the denture is rotated from function with bone loss of the pre maxilla.
There may be seven characteristics associated with this syndrome: 1. Bone loss in the premaxilla. 2 . Dropping of the posterior maxilla (tuberosities). 3 . Extrusion of the lower anterior teeth. 4 . Posterior bone loss in the mandible under the RPD. and 5 . Papillary hyperplasia of the maxilla. 6 . Decreased Occlusal Vertical Dimension. and 7 . Facial aesthetics often altered dramatically.
If not corrected, the unstable occlusion can result in progressive posterior mandibular atrophy leading to greenstick fractures. The method of reestablishing a proper occlusal relationship is discussed in this article using a conventional maxillary denture and fixed mandibular implant restoration to correct the occlusal issues.
A healthy 54 year-old female patient presented with a complete maxillary conventional denture and class I Kennedy lower partial denture (Fig. 1). The mandibular residual ridge was shaped in the form of a knife edge and the tissue covering the edentulous ridge appeared loose. The buccal shelf areas were inadequate in size to provide the denture with support. The mandible showed extrusion of both the alveolar process and remaining dentition (Fig. 2). The maxilla showed enlarged tuberosity, atrophic pre maxilla, and Papillary hyperplasia on her hard palate (Fig. 3). A limited interarch space was evident at the approximate occlusal vertical dimension (Fig. 4). The patient desired restoration of her teeth within her budgetary limits, with a preference for a nonremovable prosthesis of lower arch and more stable maxillary prosthesis, if possible. The treatment plan that was developed included a new upper denture opposing a fixed mandibular prosthesis.
Initial treatment planning began with mounted study casts, panoramic radiographic film, cephalometric radiographic film, and intraoral photographs. The mandibular cast was duplicated and a diagnostic wax-up was fabricated to identify ideal implant sites. Two surgical templates were fabricated, one involving occlusal window to indicate approximate implant sites and another outlining the buccal limitations 3 (Fig. 5, and 6). The mandibular cast was also used to fabricate an immediate complete lower denture.
The patient was required to have no food or fluids from midnight before surgery (NPO). The patient was given 0.5 mg sublingual triazolam 1 hour before surgery for sedative purposes. In addition, amoxillin (antibiotic to prevent infections), dexamethasone (corticosteroid used to minimize postoperative swelling) and ibuprofen (nonsteroidal anti-inflammatory drug used to assist in preventing swelling as well as analgesia) were also administered 1 hour before surgery. The patient’s mouth and face were scrubbed with chlorhexidine (0.12%). Bilateral inferior alveolar nerve blocks were given with 2% articaine (1:100,000 epinephrine) and local infiltration with 2% lidocaine (1:50,000 epinephrine) to assist with hemostasis. A midcrestal incision was made from the right distal first molar area to the left distal first molar area with midline vertical releasing incision. A full-thickness buccal flap was reflected and tied back to the vestibule using 2-0 silk suture material. The surgical template was inserted to mark the locations on the alveolar crest. The remaining teeth were extracted, and an alveoplasty was performed on the anterior undercuts of the buccal aspect of the ridge to level the extruded segment (Fig. 7). The template was inserted again to prepare the osteotomy within the buccal confines of the template. Teeth # 34 (21), 33 (22), 41 (25), 43 (27) and 44 (28) sites were prepared for a 3.5 mm X 10.0 mm (Nobel Direct Groovy, Nobel Biocare) endosteal root form implant and inserted. Healing caps were placed. An Amalgam tattoo at Site no. 43 (27) was removed using a round bur. The resulting defect was filled with a demineralized freeze-dried bone allograft (DFDBA) (Puros, Zimmer Dental, CA, USA) and covered with a collagen membrane (BioMend, Zimmer Dental, CA, USA).
Flap margins were trimmed with scissors to allow primary closure with no redundant tissue. Flaps were reapproximated using 3-0 Vicryl (Johnson & Johnson, Somerville, NJ) in an interrupted and continuous manner. The immediate complete lower denture was relined using CoeSoft tissue conditioner (GC America, Alsip, IL). Ice packs were given to the patient and postopepostoperative toons were reviewed.
Sutures were removed 2 weeks postsurgically, and the immediate lower denture was once again relined using soft chairside liner (GC America, Alsip, IL).
The patient was instructed not to wear the upper denture for 24 hours before this appointment to permit tissue relaxation.4-6 A final impression of the maxilla using a custom tray and polyvinylsiloxane was made.
Two months later, the patient received a final impression of the implants using impression pick up technique, a custom tray, and polyvinylsiloxane. The midline, incisal edge position, occlusal plane, buccal lip support, and anterior segment were indicated on the acrylic maxillary base and wax rim. Mandibular record bas and wax rim was used with the air of modified temporary abutment to secure the acrylic bas for vertical dimension and bite registration record.
Temporary Abutments were used on the master cast to wax up the mandibular framework (Fig. 8). Completed framework wax up was sent to be scanned and a milled titanium framework to be fabricated. The milled titanium framework (NobelProcera Implant titanium bridge, Nobel Biocare, NJ) tried in the patient mouth for passive fitness (Fig. 9).
Final try-in of the maxillary denture with teeth set in wax was made against mandibular denture teeth try-in set over the titanium framework. The occlusal plane (Curve of Spee and Curve of Wilson) was developed on the mandibular try-in hybrid denture using a Circular setup template. This plate is set against the occlusal surfaces of the mandibular teeth and is based on a 3-inch Sphere.
Denture teeth were set in a medial-positioned lingualized occlusion. Misch proposed this occlusal design, which is a modification of the occlusal scheme first developed by Payne and Pound. Only the lingual cusps of the maxillary posterior teeth are in contact with the central fossa during centric occlusion. The mandibular molar cusps are positioned medial to a line drawn from the mesial of the canine to the lingual aspect of the retromolar pad.7 The mandibular prosthesis was created in 1 peice with Procera milled titanium framework. The mandibular implants were placed within mental foramen area to accommodate mandibular flexure and limit torsion on the implants.8, 9
After esthetics, occlusion, phonetics, and comfort were evaluated both dentures were processed in heat-cured acrylic and delivered at the same appointment (Fig. 10). 10 Verification of abutments being seated required periapical films. The implant abutments were then torque to 30 Ncm. Cotton was placed over the abutment screws and sealed with Fermit-N (Vivadent, Schaan, Liechtenstein).
Final panoramic (Fig. 11) was taken to verify baseline crestal bone levels.
The patient was recalled two weeks post delivery to evaluate the occlusion, oral hygiene, and soft tissue.
Combination Syndrome is an aggressive occlusal problem that slowly develops over time. Once detected, treatment options are evaluated. Different treatment approaches should be suggested for a patient with Combination Syndrome. The choice of treatment ultimately depends on the patient, the amount of time and money she is willing to spend for the treatment, her oral condition and her desire for fixed or removable prosthesis. These options must resolve the problems of function, esthetics, and patient desires, as well as economics. To fulfill these requirements, 2 types of prostheses are available: conventional denture or an implant-retained prosthesis. The use of a conventional denture in restoring the mandibular dentition provides the least patient satisfaction as compared with a fixed prosthesis. For this reason, the patient elected to have the mandibular rehabilitation with an implant-retained prosthesis. The maxillary dentition was restored with a conventional denture because the patient had been wearing, had tolerated, and had accepted a complete denture. Also, both esthetics and economics were easily managed with this prosthesis.
Post treatment maintenance recalls appointments are essential to assure denture stability, proper occlusal scheme, and maintenance of posterior support and vertical dimension of occlusion. The patient should be recalled on 3 months, 6 months, and 12 months intervals during the first year to observe any changes in posterior support. If acrylic tooth wear and support are lost in the posterior regions, accelerated premaxilla atrophy will develop from excessive forces. Bilateral balanced occlusion is essential for long-term success.
This case study deals with treatment of Combination Syndrome. Understanding the cause can assist the practitioner in preventing further residual ridge deterioration.
The assessment of the risk of developing the combination syndrome depends on past dental history, the condition of the remaining mandibular anterior teeth, and posterior lack of occlusal support. The dentist should study the case carefully in order to assure the irreversibility of this syndrome. Implants provide a predictable method of tooth replacement offering excellent functional and esthetic benefits. Like with any complicated treatment, thorough diagnosis, planning, and implementation of treatment will result in an outstanding outcome for both the patient and dentist.
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8. Misch CE. Diagnostic casts, preimplant prosthodontics, treatment prostheses, and surgical templates. In: Misch CE, ed. Contemporary Implant Dentistry, 2nd ed. St. Louis: Mosby; 1999:143–144.
9. Goodkind RJ, Heringlake CB. Mandibular flexure in opening and closure movements. J Prosthet Dent. 1973;30: 134–138.
10. Zarb GA, et al. Boucher’s Prosthodontic Treatment for Edentulous Patients, 10th ed. St. Louis: Mosby; 1990: 400–405.
by Dr. Husain Ghadhanfari, Dr. Abdulaziz AlSanousi, Dr. Edward Monaco