The traditional two-stage protocol with delayed implant loading has achieved excellent long term results.However, this protocol is extremely demanding on our patients, who are expected to tolerate treatment protocols that could extend up to two years and necessitate endless numbers of visits.Patients are often required to be edentulous or to function with a removable prosthesis for extended periods during this treatment. Following osseointegration, a second surgical procedure is required to expose the implant fixtures and allow for prosthetic reconstruction.
Over the years, evidence has emerged in the literature that demonstrates success with a single-stage surgical approach, thereby avoiding a second surgical procedure.Immediate loading of dental implants was the next logical step, and has now increasingly become an acceptable mode of therapy.A tremendous body of literature exists to support the feasibility of functionally loading dental implants immediately after placement in the edentulous arch.
The restoration of the edentulous patient with fixed implant-supported prosthesis is a challenging and highly gratifying procedure.Our ability to predictably load dental implant fixtures at the time of surgery necessitated the development of a systematic protocol for the surgical placement and fabrication of an immediate functional and esthetic prosthesis. This paper outlines that protocol.
History
The authors’ experiences in loading fully edentulous arches immediately after implant placement have been complicated by several issues:1. the chair time required to seat temporary abutments VALUES(both straight and multi-unit) in an open flap surgical field; 2. the time required to properly position the laboratory-processed resin provisional over both straight and angulated abutments so that the screw hole accesses are either occlusal or lingual to the respective tooth facial surfaces; 3. the time required to carefully place, cure and polish flowable acrylic around the temporary abutments; and 4. completing the challenging restorative protocols on patients who are often under anesthesia.
Diagnostics
Upon clinical presentation, the clinician may be faced with a myriad of choices for both the number of implant fixtures to place and the design of the final prosthesis.However, regardless of the number of implants placed and the final prosthesis design, the success of full arch immediate loading is dependent upon the ability of the restorative dentist, implant surgeon and prosthetic laboratory to work effectively as a team.
This “team effort” commences at the earliest stages of patient evaluation – the diagnosis and evaluation of all relevant clinical records.This includes health history, diagnostic casts, face-bow articulation, photographs and appropriate radiographs.The authors believe that the use of volumetric CT images software such as SimPlant or NobelGuide and computer-milled surgical templates are diagnostic and therapeutic necessities.
This article will explore the protocol and rationale for successfully loading edentulous arch with a provisional, laboratory-processed prosthesis within 24 hours.The protocol was developed to minimize the postsurgical chair time required to manipulate, seat and cure the temporary bridge, while maximizing the laboratory’s ability to fabricate and return a completed, accurate, esthetic provisional prosthesis the next day.
The patient is a 65-year-old female with sever periodontal disease and a hopeless dentition.Extractions were performed sequentially for initial maxillary complete denture fabrication and mandibular, immediate-load fixed prosthesis.
The first step involves taking accurate full-arch preliminary and final custom-tray impressions for fabricating stable wax bite rims.This is necessary for both fully edentulous and partially edentulous patients, to establish the vertical dimensions of occlusion, esthetic profile with proper lip support and evaluate speech pattern.The clinician will then go through the basic clinical steps VALUES(set-up, try-in, etc.) to fabricate a mounted complete denture.This will serve as the template for fabricating the immediate fixed provisional restoration.
The prosthetic laboratory will, after careful articulation of the denture set-up, create an index of the denture teeth to fabricate a hollow shell resin provisional with a Rexillium metal lingual frame for additional strength.In addition, the laboratory will duplicate the resin provisional in clear acrylic.The reason for this will be explained later in this article.
Successful loading of the edentulous patient requires that both the restorative dentist and implant surgeon work together at the time of surgery.The surgical operatory is set up with two instrument tables, one for the surgeon and one for the restorative dentist.The table for the restoring dentist will have the resin provisional and clear duplicate; an assortment of implant impression copings for the planned number and platforms of fixtures being placed; at least two temporary implant abutments, again matching the platforms of the planned fixtures; calipers for marking vertical dimension; polyether impression material and disposable syringe; assorted plastic impression trays; periphery wax; slow-speed acrylic burs; surgical ink pen; flowable, light-cured resin; and a laboratory prescription and bag.
Prior to administering the local anesthetic, the patient is seated upright with dentures in place and asked to softly bring the lips together.Surgical ink is used to make a dot on the nose and chin, and calipers are used to record the vertical dimensions.A small piece of surgical tape can be substituted for the surgical marker.This caliper measurement is the one constant to permit the accurate reestablishment of vertical dimension after the implants are placed.
The resin provisional and clear duplicate shell VALUES(having been fabricated from the denture set-up) is then applied to the occlusal surface of the resin provisional, and a registration is obtained with the opposing dentition or denture.This is done outside the mouth, since the resin provisional, at this stage, would have no positional integrity in the mouth.
Using appropriate techniques, the periodontist creates osteotomies to allow placement of implants with torque values greater than 35 Ncm.Once the implant positions are verified and they are inserted, open-tray impression copings are seated and light suturing of the open soft-tissue flaps is completed around each coping.
A stock plastic perforated tray is measured either on the master cast of chair side in the mouth, and an ink mark is made on the tray surface where each impression coping touches the tray.An acrylic bur is then used to cut out a small window at each ink mark site so that the head of each impression coping is clearly visible.A small amount of periphery wax is placed over each impression coping screw head to prevent impression material from blocking the screw access.A small piece of medium soft pink wax is softened in warm water and pressed over the impression coping tray cutouts.This is to prevent flowable impression material from rapidly extruding through the openings, thereby permitting a neater working field.
The impression is taken using Impregum with both disposable syringe and plastic tray.Syringe material is carefully expressed around the base of each impression coping, and the loaded tray is seated over the open tray copings until their heads can be palpated and seen through the pink overlying wax.At that time, with the tray firmly in place, the assistant, using a plastic instrument and cotton applicators, clears wax and impression material from ass of the screw access holes.
Once the impression material is set, the coping set screws are backed out, and the tray can be removed easily from the patient’s mouth.It is important to make certain that the set screws are completely unscrewed and lifted several millimeters with a curved hemostat prior to attempting to remove the impression from the mouth.This is to prevent screw-thread binding inside divergent-placed implant fixtures, which can cause a tear in the impression.
The next procedure was developed to enable the dental laboratory to accurately mount the fixture-level master cast against a cast of the opposing dentition on the articulator.Once this is achieved, the laboratory must be able to properly position the resin provisional shell on the implant master cast, so that temporary implant abutments can be cured in place.
With multiple prior full-arch immediate load cases, repeated attempts to seat the laboratory-completed provisional on straight and multi-unit angled abutments resulted in a procedure that was time consuming and, because of the need to repeatedly refinish acrylic, often damaging to the esthetic of the laboratory-glazed resin provisional.The solution was the creation of a clear duplicate provisional shell that functions as an occlusal guided index.
The clear stent and resin provisional are occlusally interchangeable; thus, either can be mounted against the opposing dentition at the dental laboratory.First the clear duplicate stent is seated in the mouth with the occlusal surface inside the previously created bite registration.The patient’s edentulous jaw is guided closed until the correct vertical dimension is re-established and the stent is then removed from the mouth.
Temporary abutments are then seated on two of the implants.The clear duplicate stent is partially seated onto the temporary abutments, and surgical ink is used to mark the location on the stent where seating interference occurs.Acrylic cutting burs are then used to relieve the stent until it fully seats into occlusion with the opposing dentition.If the temporary abutments interfere with the occlusal positioning because they are too long, they should be shortened with a separating disc, using a laboratory abutment handle.Since the only function of the clear stent is to serve as a duplicate of the actual occlusal design of the resin provisional, it can be adjusted rapidly with laboratory acrylic burs until it fully seats.
Critical to the success of this step is the measurement of the vertical dimensions, again with the previously set calipers.Once this is verified and the patient is occluding with both arches into the occlusal registration created prior to surgery, the clear stent must be rigidly secured to both temporary implant abutments.This is achieved by flowing syringe-able, light-cured composite resin around the temporary abutments so that most of the voids in the adjacent acrylic are filled.Care must be taken so resin does not obliterate the screw access holes in the temporary abutments.
Once this is completed, each abutment area is light cured until set.The abutment screws are retrieved, and the clear acrylic stent is removed with both temporary implant abutments rigidly secured in place.Healing abutments are then placed over the implants and the patient is discharged with instructions to return the following day to the restorative dentist’s office.
At this time, the implant-level impression with analogues and the duplicate clear stent with secured, temporary implant abutments are wrapped and forwarded immediately to the dental laboratory.They should be accompanied by the previously mounted articulation of the patient’s denture set-up stone casts.
The laboratory will create a fixture-level implant master cast using Type III dental stone, and with the articulated mounted denture set-up, will mount the clear acrylic resin using the two temporary abutments.Once articulated, they will use a facial profile tooth index and bite registration to substitute the resin provisional accurately on the master cast.The laboratory will then process temporary abutments inside the provisional and complete its fabrication.
The healing abutments are removed when the patient returns the next day.No local anesthesia is required.The provisional prosthesis is inserted and secured with torque tight screws.The fixtures are torqued to 20 N/cm.the patient is discharged with home care instructions, which include chlorhexidine rinses and a very soft diet.
At four weeks postoperative, the patient remains completely asymptomatic and extremely happy.
Discussion
The ability to provide our patients with a fixed, esthetic and functional prosthesis one day following surgery has been a tremendous motivating factor in our patients’ desire to proceed with implant dentistry.The confidence and appreciation expressed by our patients upon completing this protocol and experiencing the collaborative team effort of the periodontist, restorative dentist and prosthetic laboratory are unprecedented in dentistry.
This simplified protocol has been established to allow the restorative dentist to offer his or her patients with opportunity to proceed with implant dentistry in a comfortable and expeditious manner.