Full mouth rehabilitation of a patient with mandibular implant screw retained Fp-3 prosthesis opposing maxillary acrylic removable over-denture
A 52-year-old white woman was initially seen with an existing maxillary tooth supported over-denture opposing edentulous mandibular arch []. The patient had initiated treatment previously with a general dentist, but decided to seek specialty care for the completion of her treatment. Fabrication of screw retained hybrid prosthesis was planned for the mandibular arch and a new over-denture for maxillary arch. The unfavorable sinus anatomy in the posterior maxilla and patient's unwillingness for bone grafting to facilitate implant placement precluded the placement of implants in the maxillary arch []. The treatment options presented to the patient also included the fabrication of an implant-supported over-denture, but the patient's desire was to eliminate a removable prosthesis in the mandible. The following clinical and laboratory procedures were performed.\nA full thickness mucoperiosteal flap was raised in the mandibular arch from distal to mental foramen on one side to mental foramen on the other side. In the right quadrant, implants (Tapered self-thread, Hi-Tech Implants, and Life care implant system) were placed in the 2nd premolar (4.2 mm × 10 mm), lateral incisor (4.2 mm × 10 mm) regions. In the left quadrant, implants were placed in 2nd premolar (4.2 mm × 10 mm), lateral incisor (4.2 mm × 10 mm) and regions. The implant dimensions were selected with the help of a computed tomography scan and 3D reconstructive image []. A total of four implants were placed in the mandibular arch with a help of surgical stent. The flap was closed using the horizontal interrupted sutures. After 1 week, the sutures were removed and an immediate denture was relined with a permanent soft denture liner (Permasoft, Dentsply, York, PA, USA) and inserted.\nAfter a waiting period of 4 months, an (Orthopantomograph 10E, Siemens) OPG was obtained to evaluate the bone to implant contact percentage [] and later stage II surgery was performed under local anesthesia cover screws were exposed and healing abutments were placed and the flap sutured.\nMaxillary and mandibular arch impressions were made using alginate (Tulip Alginate Impression Material, Cavex, Holland Bv, Haarlem, Holland). A conventional special tray was fabricated for the maxillary arch and a custom open tray was fabricated in acrylic resin (Autopolymerizing acrylic resin, ALIKE™; GC America, ALSIP, USA) for the mandibular arch. The open tray was verified in the patient's mouth. After 1 week, the healing abutments were removed, and impression copings were connected to the implants (Impression Coping Pick-up Type, 4 mm Profile; 3i Implant Innovations, Palm Beach Gardens, Fla.). These open tray impressions copings were stabilized with 23 gauge ortho wire and blocked out with acrylic resin (Autopolymerizing acrylic resin, ALIKE™; GC America, ALSIP, USA). The mandibular impression was made with monophase polyvinyl siloxane impression material (Aquasil Lv Ultra, Smart Wetting Impression Material, Dentsply, Detrey Gmbh, Konstanz, Germany). Border molding was completed with green stick compound and secondary impression was made using addition silicone impression material (Aquasil Lv Ultra, Smart Wetting Impression Material, Dentsply, Detrey Gmbh, Konstanz, Germany) for the maxillary arch. The impressions were poured in die stone (Ultrarock, Kalabhai Karson Pvt. Ltd., Mumbai, India) Master casts were recovered and trimmed and record bases and occlusion rims were fabricated. Patient returned for recording of maxillomandibular relations and tooth selection. Master casts were then mounted on a semiadjustable articulator (Hanau Modular Articulator System, Waterpik Technologies Inc., Fort Collins, Colo.). The path of insertion deviated considerably, so castable abutments were used to produce the optimal angulations. Wax up for framework fabrication was carried out. The framework was waxed, cast, recovered, and fitted on the master cast. Disclosing media (Kerr's Disclosing Wax; Kerr, Romulus, Mich. and Occlude; Pascal Co Inc., Bellevue, Wash.) were used to evaluate the fit of the framework and to guide adjustment procedures. The fit was refined until the framework seated passively on the master cast. The metal framework was tried in to evaluate and verify a passive fit intra-orally []. Disclosing media was used to discern any fit discrepancies. Adjustments were performed, and abutments were removed from the implant fixtures and healing abutments reconnected. The mandibular denture teeth were waxed to the hybrid framework, and a final wax try-in was performed to verify and correct maxillomandibular relations. At this appointment, the customized abutments along with the framework were connected to the implants for the final wax try-in. At this time an OPG was made to evaluate the fit between frameworks and implant interface []. The maxillary tooth supported over-denture was invested/flasked and processed by use of the maxillary master cast as any conventional complete denture. However, the mandibular hybrid prosthesis was invested without the master cast. The internal aspects of the casting that fit on the abutments were blocked out with the polyvinyl-siloxane impression material, and the prosthesis was invested directly into the lower half of the processing flask. The investing, flasking, and processing procedures were then completed. The prostheses were finished and polished, a clinical remount was performed to allow for refinement of occlusal contacts, the hybrid prosthesis was screw retained and provisional cement (Temp Bond; Kerr) was used to cover screw access hole. Maxillary over-denture and Mandibular hybrid prosthesis were inserted []. Hygiene techniques were reviewed, and patient was scheduled for recall and maintenance.\nOcclusion was evaluated using guided closure and was considered as: Good, if centric relation (CR) coincided with centric occlusion (CO); moderate, if minor (<0.5 mm) deviation was observed between CR and CO; poor, if clear (>0.5 mm) deviation was observed between CR and CO. Articulation was considered as good when it was fully balanced during lateral movements performed from CO, otherwise it was considered poor. Presence or absence of frontal contact in CO was also noted.[]\nRetention of the maxillary tooth supported over-denture was examined using the following scores: (1) good = good resistance to vertical pull, and sufficient resistance to lateral forces; (2) satisfactory = slight to moderate resistance to vertical pull, and little or no resistance to lateral forces; and (3) poor = no resistance to vertical pull and lateral forces; the denture falls out of place. Stability was determined with the following criteria: (1) good = slight or no rocking on denture-supporting structures when under pressure; (2) moderate = moderate rocking on supporting structures under pressure; and (3) poor = extreme rocking on supporting structures under pressure.[]