This article describes the method of temporary prosthesis screw fixing immediately after implant installation in the conditions of complete lower jaw adentia with following prosthetics by permanent orthopedic construction.
Long-term investigations have proven the efficacy of patient rehabilitation with complete jaw adentia using implants. There are several protocols of upper and lower jaw adentia elimination, where the number of the construction implants and ways of temporary and final prosthesis fixation are mentioned. Several methods of immediate prosthetics on implants are proposed. This article describes the method of immediate implant load using temporary prosthesis, attached using screw fixation. Prosthetics of a complete toothless jaw with immediate occlusion load is indisputably advantageous. On the day of surgery the patient can return home with normally looking and functioning teeth. The number of following procedures is decreased. The gum has enough time to form, and the permanent prosthesis would be better adapted to soft tissues. A clinical observation. A 57-year-old patient has referred to the clinic concerning manufacture of a non-removable dental prosthesis on lower jaw, using implant support. Objective findings included considerable alveolar crest atrophy (see photograph 1 below).
Satisfactory fixation of a complete removable prosthesis was impossible. Following diagnostic models installation into the articulator, wax modeling was performed. The wax model was used for estimation of occlusion, aesthetic parameters, and interrelation between teeth and alveolar crest (gingival contour). Panoramic X-ray examination, determination of alveolar crest thickness and mucous tunic thickness were also conducted.
The following indications for prosthetics of a complete toothless jaw with immediate occlusive load according toDIEM (3i) program were taken into account:
1. Adequate bone quality (3-rd type and higher).
2. Bone height no less than 12 mm, which allows installing the implant of minimal length 10 mm.
3. Bone thickness no less than 6 mm, suitable for installation of an implant of minimal diameter 4 mm.
4. Adequate arc curvature and distances between foramina, which allows creating correct mesiodistal ratio between prosthesis with consoles and occlusion on the first molar.
Mesiodistal ratio determination (see Fig. 1 below):
mesiodistal ratio is a maximal length of prosthesis console from the most distal implant to the distal edge of the prosthesis;
in order to determine this ratio, we measured the distance between two parallel straight lines.
The first of them is lined along the lingual edges of distal implants, and the second one is lined through the center of frontal implant; after multiplying the obtained result by 1.5, we have obtained the maximal patient’s console length, equal to 13.5 mm. A temporary prosthesis has been manufactured preliminarily; its edges were cut so that the distance from the most distal implant to the distal edge of the prosthesis comprised 13 mm (see photograph 2 below). Surgical model, duplicating a removable prosthesis, has been made of transparent plastic. Guide holes for 5 implants were perforated in the surgical model, distributed in its frontal part from the 1-st left premolar to the 1-st right premolar between foramina (see photograph 3 below).
For occlusion position fixation, material for occlusion registration was administered on tooth masticatory surface, the patient was allowed to make maximal occlusion, and the abovementioned manipulation was repeated for surgical model. Following incision along the crest and foramina visualization on alveolar crest, position of mandibular nerve was indicated using spherical dental drill. Considering the foramina position an orientation point, the surgical model was installed in the mouth, the implants’ position was indicated, the holes for implants were perforated, and Osseotite implants, sized 4 mm in diameter and 11.5 mm in length, were embedded according to the protocol, with torsion strain 20 N/cm. All of the five implants were standing in the bone firmly. Later, IOL abatements were installed and twisted using dynamometer screwdriver with the strain of 20 N/cm, around which mucosal-periosteal graft was sutured by interrupted stitches, using absorbable suture material.
In order to separate surgical and prosthetic areas, robberdam has been established. The frontal part of temporary prosthesis was filled with basic impression material, the lower prosthesis was matched with the upper one, using imprints for occlusion registration, and the patient was allowed to close her mouth, so that IOL abatements were reflected inside the temporary prosthesis. The holes were perforated in temporary prosthesis in abatement position sites (see photograph 4 below). Temporary IOL cylinders were installed on the abatements and fixed with Gold-Tite screws (see photograph 5 below). Self-hardening plastic was applied inside the prosthesis, the latter was placed into the oral cavity, and the patient was allowed to close her mouth with registration imprints. Following the plastic polymerization, the cylinders height was adjusted to the prosthesis level from the lingual side, using hardmetal shear-cutting borer (see photograph 6 below). The plastic excess was removed from internal and external prosthesis surface (see photograph 7 below). The occlusion was adjusted using articulation paper, minimizing lateral load. The prosthesis was polished. The prosthesis was mounted on IOL abatements and fixed with Gold-Tite screws, applying the strain 10 N/cm. Protective material was placed over the fixation screws, the holes were filled with plastic and polished (see photograph 8 below). The patient was explained the rules of temporary prosthesis hygiene and care.
In 12 weeks, manufacture of permanent orthopedic construction was initiated. After temporary construction removal one can see well-adapted soft tissues (see photograph 9 below). X-ray image shows integrated implants (see photograph 10 below). Cauterizable abatements were attached to IOL abatements by screws, and the impression was obtained in silicone modeling mass using an individual impression tray. Analogues of implant supports were screwed into impression elements. SAM orthopedic facial arc was installed on upper jaw, and the impression was obtained. Central occlusion height was registered using wax roller. The manufacture was carried out in SAM articulator.
One of obligatory conditions of proper implant functioning is precision of dental prosthesis manufacture. Meso- and suprastructures, mounted on implants with effort, result in pains, osseous tissue decrease, and osteointegration loss. Inaccurate attachment of meso- and suprastructures to osteointegrated implants can be determined in several ways.
We used two methods:
1. In order to determine conformity precision, we used silicone material first on the model, and then in oral cavity.
2. Metal framework was fixed with one screw near the external edge of the construction to the implant analogue and to IOL abatement in oral cavity (Sheffield-test). Here, no gap was formed between mesostructure, the analogue and IQL abatement (see photographs 11-12 below).
The metal suprastructure was supplemented with ceramic, renewing red-and-white aesthetics. The prosthesis was fixed in oral cavity with Gold-Tite screws, using the strain 10 N/cm, and occlusion was verified using articulation paper. Protective material was placed over fixation screws; the holes were filled with composite material and polished (see photographs 13, 14, 15 below). The patient was explained the rules of permanent orthopedic construction hygiene and care.
The dental prosthesis conformed to the following requirements:
1. It ensured adequate possibility of oral cavity hygiene conduction.
2. It possessed excellent functional characteristics.
3. It had good aesthetic properties.
4. It ensured excellent phonetics.
At present, the patient feels social comfort and satisfaction.
Head doctor, «Clinic of aesthetic dentistry» Duda V.V.