Bicon Surgical Techniques (2004)

Dear colleagues, the procedures and techniques depicted have been successfully utilized over the years by many Bicon clinicians. However, as any experienced dentist knows, there are many ways of achieving a particular result and by no means are the depicted techniques the only way of providing for your patients’ needs. Clinicians for whom the Bicon system is a new experience should be impressed with the flexibility, forgivingness, and facility with which Bicon implants can be placed and restored even in challenging clinical cases. Many of Bicon’s beneficial restorative attributes such as the extraoral cementation of crowns and the Bicon integrated abutment crown, are directly related to the implant’s elegant design with a one point five degree locking taper connection, which provides for three sixty degrees of universal abutment positioning. Hopefully, with the depicted techniques, you will enjoy the benefits of the Bicon system, such as never again having to apologize to your patients for a dark metallic gumline. Selecting the appropriate length and width of an implant depends upon the available bone and the expected occlusal loads. In general, choose the widest, but not necessarily the longest implant possible. Panoramic and periapical radiographs, models, and a clinical examination are used to determine if enough mesial distal space and vertical bone height, free of anatomic problem areas, exist to appropriately place a Bicon implant. Using a transparent overlay, which depicts implant outlines of actual size and one hundred and twenty five percent of the actual size may prove helpful in selecting an appropriately sized implant. However, since radiographs are not necessarily precise representations, their magnification and or distortion must be considered while using them with an implant overlay to determine an appropriately sized implant. With digital radiography, only computer generated and adjusted simulations should be used. To consistently place implants well, it is essential to have knowledge of the intended prosthesis prior to the patient’s surgical visit for the fabrication of a surgical template. Mounted casts and a diagnostic wax up of the teeth to be replaced are usually necessary for the fabrication of a variety of surgical templates that will aid the surgeon in the appropriate placement of an implant. After making an impression and a subsequent cast of the diagnostic wax up of the intended restoration, a vacuum formed template is formed onto the cast from thin template stock, which is used in restorative dentistry for the chairside fabrication of transitional restorations. A hole slightly larger than the diameter of a two millimeter pilot bur is drilled in the center of the incisal edge or occlusal surface of the template in the location of the intended tooth to facilitate the pilot bur’s positioning. For stability, the vacuum form template, if possible, is trimmed to include at least one tooth distal to the implant site and three or four teeth mesial to the site. Palatal templates can be fabricated on a stone model or by duplicating or using an existing removable prosthesis. When using a duplicated stone model of a diagnostic wax up, draw a line through the incisal edge and occlusal surfaces of the teeth and another line on the facial surface through the center of each tooth to be replaced bisecting the drawn incisal or occlusal line. Remove the stone representing the lingual half of the teeth to be replaced. Mold acrylic onto the lingual aspect of the modified model up to the level of the central fossa or incisal edge of the teeth to be restored. Cut a two point five to three point zero millimeter wide groove in the acrylic corresponding to the center and long axis of each intended tooth to be replaced. When using an existing or duplicated prosthesis, draw a line on the occlusal aspect of the prosthesis bisecting the incisal edges and central fossa and another on the alveolar ridge side of the prosthesis corresponding to its greatest concavity. To afford better visibility for the surgeon, the buccal aspect of the prosthesis is removed to the level of the central fossa or incisal edge and to the line corresponding to the greatest concavity of the alveolar ridge side of the prosthesis. The slot, slightly wider than the two millimeters, is made in the long axis and center of each tooth, which will act as a guide for the pilot drill. After the appropriate local anesthesia, initiate or a broad based pedicle flap with the crestal incision slightly palatal or lingual to the actual crest. The envelope flap is recommended for use in the posterior part of the mouth for two stage surgical placements and in areas with a narrow alveolar ridge. The flap consists of two parallel incisions next to the papillae joined by one transverse incision which is made palatal or lingual to the crest of the ridge. The semilunar flap design is recommended for aesthetic areas as well as for the one stage technique and for the immediate stabilization and functioning technique. The semilunar flap consists of a pedicle flap type incision with its base on the lingual or palatal aspect of the ridge. Caution is advised when preparing an osteotomy using the semilunar flap since visualization of the implant site is limited to only the crestal aspect of the bone. Therefore, inadvertent buccal or lingual fenestrations are more likely to occur. Simply stated, the pilot osteotomy to the extent possible should be positioned in the center of the edentulous space and with the same trajectory of the proposed tooth. Using a surgical template as a guide with a two millimeter pilot drill in an eighteen to one reduction handpiece, the initial penetration for the pilot osteotomy is made completely through the crestal cortex with the drill rotating at approximately eleven hundred RPM with external sterile irrigation. It is advisable to use a two handed drilling technique where one hand guides the drill while the other hand applies the apical drilling pressure. After half of the necessary depth of the osteotomy is achieved, the pilot drill is removed and a paralleling pin is placed into the newly formed osteotomy to assess the positioning and trajectory of the preliminary pilot osteotomy. A vacuum form template is placed over the paralleling pin to confirm the appropriateness of the preliminary osteotomy while it is still possible to change its trajectory. If the trajectory is appropriate, drilling is continued with a pilot drill to the depth marking which will allow for the chosen implant to be seated below the bone to the extent that it is, for aesthetic reasons, five millimeters below the crest of the buccal soft tissue cuff. Therefore, the extent to which the implant is placed below the crest of the bone depends upon the thickness of the overlying mucosa. If multiple implants are being placed, paralleling pins should be inserted consecutively into the completed pilot osteotomies to facilitate establishing the trajectory of the pilot drill for the preparation of subsequent osteotomies. While preparing an osteotomy on a slope, the leveling of the uneven heights of bone at the orifice of a pilot osteotomy is advisable to avoid chattering and potential displacement of the wider latch reamers. Leveling may be achieved by rotating a sulcus reamer as a planisher on a two millimeter guide pin inserted into the two millimeter osteotomy. Or alternatively, by using a round bur to even the bone level around the orifice of the osteotomy. The pilot osteotomy is initially widened with a two point five millimeter latch reamer and then with successively wider latch reamers in a four hundred to one reduction handpiece without irrigation until the diameter of the intended implant is achieved. Reamer burs rotating in excess of fifty rpm may frictionally overheat the bone potentially causing failure of an implant to integrate. However, in exceptionally dense bone, it may be necessary to use the narrower diameter latch reamers rotating at 1000rpm with external water irrigation to achieve an osteotomy and reserve the 50rpm reamer bur speed for the reamer diameter of the intended implant size. For the immediate placement of a maxillary anterior implant, it is advisable to avoid a buccal perforation by initially drilling into the palatal wall the socket more perpendicularly than the intended trajectory and immediately upon engagement of the pilot drill, change the drill’s trajectory to be more parallel with the adjacent teeth and the intended restoration. To facilitate achieving an appropriate osteotomy depth, the narrow reamers have horizontal markings at the levels of eight, eleven, and fourteen millimeters. And the five millimeter and wider reamers have an additional horizontal marking at the six millimeter level. If the trajectory is appropriate, drilling is continued with a pilot drill to the depth marking which will allow for the chosen implant to be seated below the bone to the extent that it is, for aesthetic reasons, five millimeters below the crest of the buccal soft tissue cuff. Therefore, the extent to which the implant is placed below the crest of the bone depends upon the thickness of the overlying mucosa. The latch reamers are best used in a two handed drilling technique. While one hand guides the trajectory of the drilling, the other hand applies the apical inserting and coronal withdrawal force. In order to prevent bone shavings from clogging the flutes of the reamers and overheating the walls of the osteotomies by burnishing, the reamers, while continuing to rotate, are intermittently withdrawn from the osteotomy for the harvesting of bone from their flutes. The harvested bone is collected in a flexible silicone Dappen dish for its use as an autogenous graft over the seated implant. Alternatively, hand reamers threaded on a straight handle may be used to widen maxillary pilot osteotomies. Their use facilitates a clinician’s perception of the harder cortical layers of bone around the osteotomy as well as the movement of the thin walls of an osteotomy. Therefore, the use of hand reamers enhances the clinician’s ability to avoid inadvertently penetrating the nasal floor, the maxillary sinus, or the walls of an osteotomy. A hand reamer’s single cutting surface allows for only cutting the palatal side of an osteotomy while expanding the buccal ridge side of the osteotomy as it is rotated for only one hundred and eighty degrees with cutting pressure rather than a full three sixty degrees with cutting pressure. The sterile blister package containing the selected implant is removed from its cardboard folder by the circulating assistant. The assistant then tears open the Tyvek backing on the blister package and carefully without contaminating it drops the sterile inner plastic bag containing the implant and the plastic healing plug inserter onto the sterile instrument tray. The scrubbed assistant or the dentist grasps the implant through the plastic bag and opens the sterile package with a pair of scissors. All implants are packaged with the healing plug inserter attached. Grasp the healing plug inserter with gloved fingers or forceps and insert the implant into the prepared socket. The implant should not touch anything prior to being placed into the bleeding prepared socket. The socket is not flushed because it is desirable to have an undiluted clot form within the implant placement site. Rotating the assembly while pressing apically during seating will help to fully seat the implant. The implant should be wet with blood during seating. After its initial insertion with a twisting and pushing motion, the blood wetted implant may be definitively seated by tapping on it with either an implant seating tip or to an implant inserter retriever instrument attached to a straight or offset handle. The implant seating tip may be inserted into the handle of the black polyethylene plug or alternatively, it may be placed directly into the well of the implant. When the seating tip is inserted directly into the well of an implant, it should be fully seated prior to the application of any force since any distortion of the walls of the implant’s well may prevent the proper engagement of an abutment’s locking taper connection and possibly may result in the subsequent loosening of an unsplinted maxillary anterior abutment. It is essential for a clinician to fully understand how an implant is engaged and disengaged from the instrument prior to using it intraorally in an osteotomy. An implant is engaged by pressing the shaft of the instrument into the implant’s well. And an implant is removed from the inserter retriever instrument by holding the threaded knob or straight handle stationary while turning the knurled portion of the instrument in a counterclockwise direction. The descriptive terminology of the surgical techniques for placing implants refers to how soon after the extraction of a tooth the implant is being placed and to the manner in which the implant is treated after it has been definitively seated in its osteotomy. Immediate placement refers to an implant being placed on the same day as the tooth’s extraction. Whereas a delayed immediate placement refers to placing an implant prior to the remodeling of the extracted tooth socket. The two stage technique consists of cleanly cutting the black polyethylene healing plug with a pair of scissors or healing plug cutters either intraorally or extraorally so that the plug is smooth and flush with the crest of the bone when it is inserted into the well of the seated implant. To facilitate locating the implant at the time of its uncovering, the healing plug should not be placed below the crestal level of the bone over the implant. If a sharp edge were to be left on the plug, it may act as an irritant to the mucosa resulting in an operculum like fenestration often with a slight purulent exudate. Polishing and reinserting the plug usually resolves any soft tissue irritation. Alternatively, healthy soft tissue can be achieved by inserting a healing plug that is definitively transmucosal as though it were a one stage technique. After the healing plug has been inserted into the well of the implant, the bone that was collected in a flexible silicone Dappen dish during the preparation of the osteotomy is gently packed around and over the implant. In order to prevent seepage of oral fluids into the implant site, it is desirable to achieve a tight closure with a suturing of the mucoperiosteal flaps. The use of a resorbable cellulose material over the bone graft may facilitate the closure of some implant sites. The two stage technique is the most reliable technique in that the implant is not subject to the extraneous factors inherent with the one stage or immediate loading techniques. After three or four months of appropriate healing for osseointegration, the implant is surgically uncovered. Although a tissue punch technique may be used for the uncovering if the implant can be readily located through mucosa, it is more desirable to use a flat procedure which preserves the buccal mucosa for the emergence profile of the intended abutment. In non aesthetic areas, a slightly lingual or palatal crestal incision is made with only enough periosteal reflection to expose the black healing plug. For aesthetic areas such as the maxillary incisors, the incision should be semilunar. Relieving incisions for the semilunar flap can be made near and along but not through the gingival margins of the adjacent teeth. After locating the black healing plug, complete removal of any overlying bone or soft tissue with a curette, sulcus reamer, rongeur, or round bur is essential to facilitate the removal of the healing plug by twisting a healing plug remover or number one hundred ten root canal reamer into its center hole before removing it manually with a twisting and pulling motion. Alternatively, the plug may be removed by grasping it with a small soft tissue rongeur or by engaging it with a number four round bur in a latch handpiece. After removal of the black healing plug, a guide pin corresponding to the implant’s two millimeter or three millimeter well diameter is completely seated into the implant’s well to ascertain the success of its osseointegration by evaluating its stability. Immobility indicates osseointegration whereas slight lateral mobility would indicate that additional time may be required for further integration. And any apical mobility usually indicates failure of the implant to osseointegrate. After osseointegration has been confirmed, successfully wider sulcus reamers attached to either a straight handle or knob are rotated on a guide pin with apical pressure to remove any bone which may prevent the seating of the intended abutment. When deeply positioned implants are being restored with long shafted abutments such as the five millimeter by six millimeter stealth abutment, a red extended guide pin should be used. Its use will prevent the unnecessary removal of bone over the implant. Alternatively, if an implant level impression is to be taken, either a red two millimeter or a green three millimeter impression reamer is used with a guide pin to remove any tissue which might Since the one stage surgical technique employs a transmucosal abutment at the time of implant placement, a second surgical procedure is unnecessary for the placement of a permanent abutment. However, care must be taken not to transmit destabilizing forces to the implant through the transmucosal abutment during its healing for osseointegration. The one stage technique should be avoided in conjunction with the use of a removable prosthesis or with non compliant patients who may inadvertently apply destabilizing pressures onto the transmucosal abutment. For the one stage technique, it may be necessary to contour the orifice of the osteotomy with a sulcus reamer to accommodate the insertion of the intended transmucosal abutment. The transmucosal abutments should be wide and high enough to support the interdental papillae without encroaching upon them. They should also be narrower buccally than the intended final abutment to possibly prevent any undesirable recession of the buccal mucosa. The abutment should only extend minimally above the mucosa to minimize the effect of any adverse forces being applied to it by the patient’s tongue. The transmucosal abutment can be inserted into the implant either intraorally or while the implant is being grasped by its plastic envelope packaging. If the temporary abutment is inserted extraorally, it can be used as a handle to transport the implant to its osteotomy. This is particularly useful when the abutment is being used to prevent the inadvertent overseating of an implant into the maxillary sinus. After a period of healing for osseointegration, the transmucosal temporary abutment is removed and the implant is evaluated for osseointegration prior to its restoration. Hopefully, this video has given you a better understanding of proven surgical techniques for the successful placement and restoration of Bicon implants. While the techniques depicted are not the only way to provide for your patients’ needs, an adherence to the principles shown throughout this video should give you the confidence to offer your patients the exceptional benefits of the Bicon dental implant system.