Angiocentric T-cell lymphoma of the lung mimicking metastatic carcinoma. Case report

Displacement of soft tissue adjacent to an implant abutment is arduous. Currently, gingival retraction cord is used before making an impression for cement-retained implant restoration. This article presents a new impression system for a cementable abutment/implant. The advantages of a cement-retained implant crown are described. This system provides efficient and accurate impressions.     

Affordable implant prosthetics using a screwless implant system

Many dentists have been reluctant to place dental implants because they have found that most implants are costly and time-consuming to place and have long-term maintenance problems. Most of these problems are caused by using screws to connect the abutment to the implant, the crown to the abutment or both. The use of a screwless implant system and conventional prosthetics, the author contends, can make implant dentistry affordable, versatile and easy to incorporate into all general dental practices.     

The custom implant impression coping: technical note

Unsupported soft tissue can collapse around a submerged implant or abutment head during the time interval between removal of the provisional prosthesis and placement of the impression material. A technique is described for accurately recording the implant or abutment position as well as the position of the soft tissue for a single tooth restoration using the provisional prosthesis as a custom implant impression coping.     

One-stage surgery with a nonsubmerged implant system

Although nonsubmerged implant surgery can reduce patient trauma and costs by eliminating the uncovering procedure, one-piece implants cannot be shortened for esthetic results. However, a new implant design that comes preattached on a multipurpose collar is used for insertion, nonsubmerged healing, and as an abutment base. For submucosal margins, the collar can be replaced by an esthetic abutment that connects directly to the implant. Surface treatments include midsections roughened by hydroxyapatite or titanium plasma spray coatings, with smoother, acid-etched necks and self-tapping apical ends. Screw-retained, friction-fit abutments offer prosthodontic stability and uniformity, despite the submucosal implant type.     

An evaluation of torque (moment) on implant/prosthesis with staggered buccal and lingual offset

The supposition that staggered buccal and lingual implant offset is biomechanically advantageous was examined mathematically. The method of evaluation utilized a standard hypothetical geometric configuration from which implants could be staggered buccally and/or lingually in both arches. Torque (moment) values were calculated at the gold screw, abutment screw, and 3.5 mm apical to the head of the implant. Comparisons were made in percentages of change from the hypothetical standard to the buccal and/or lingual implant offset. In the maxillary arch, buccal offset decreased the torque (moment) while lingual offset increased it. If more lingually offset implants were present in the maxillary restoration, the total torque would be greater than if they were all in a straight line. Staggered buccolingual implant alignment often requires abutment reangulation. The resultant line of force produced by occlusal anatomy usually results in buccal inclination in the maxillary arch and lingual inclination in the mandibular arch. As a result, mandibular implant/prostheses are greatly favored over similar maxillary configurations because the mandibular resultant line of force usually passes lingually, closer to the components and supporting bone and considerably less torque is produced. Therefore, the concept of staggered offset for multiple implant-supported prostheses can be utilized on the mandible but is not recommended for the maxilla where maximum uniform buccal implant orientation is advised.     

Two applications of transmucosal milled ceramic in implantology: preliminary clinical examples

Two new implant systems, the Compound Implant and the TFM coping/abutment, are based on the association of titanium in the infrabony portion and a dense milled ceramic in the transgingival portion. The coating of zirconium ceramic on the transmucosal collar of the Compound Implant is particularly indicated for a single-stage surgical implant technique. The isolating properties and the high wettability of this material favor gingival healing and reduce the accumulation of plaque; the esthetic collar permits a supragingival or juxtagingival cervical margin favoring plaque control and minimizing the consequences of tissue remodeling. The hardness of the ceramic also allows it to undergo conventional prophylaxis with ultrasonic scalers without alteration of its surface quality. In addition to the above-mentioned advantages, the TFM coping/abutment, an implant-prosthesis connector in alumina ceramic, for use in a two-stage technique, provides electrogalvanic isolation of the implant, and personalized abutment preparation allows for simplified fabrication of an implant-supported prosthesis.     

The mucosal attachment at different abutments. An experimental study in dogs

The present experiment was performed to examine if the material used in the abutment part of an implant system influenced the quality of the mucosal barrier that formed following implant installation. 5 beagle dogs were included in the study. The mandibular premolars and the 1st, 2nd and 3rd maxillary premolars were extracted. Three fixtures of the Br?nemark System were installed in each mandibular quadrant (a total of 6 fixtures per animal). Abutment connection was performed after 3 months of healing. In each dog the following types of abutments were used: 2 "control abutments" (c.p. titanium), 2 "ceramic abutments" (highly sintered Al2O3), 1 "gold abutment", and 1 "short titanium abutment". This "short titanium abutment" was provided with an outer structure made of dental porcelain fused to gold. Following abutment connection a plaque control program was initiated and maintained for 6 months. The animals were sacrificed and perfused with a fixative. The mandibles were removed and each implant region was dissected, demineralized in EDTA and embedded in EPON. Semithin sections representing the mesial, distal, buccal and lingual aspects of the peri-implant tissues were produced and subjected to histological examination. The findings from the analysis demonstrated that the material used in the abutment portion of the implant influenced the location and the quality of the attachment that occurred between the periimplant mucosa and the implant. Abutments made of c.p. titanium or ceramic allowed the formation of a mucosal attachment which included one epithelial and one connective tissue portion that were about 2 mm and 1-1.5 mm high, respectively. At sites where abutments made of gold alloy or dental porcelain were used, no proper attachment formed at the abutment level, but the soft tissue margin receded and bone resorption occurred. The abutment fixture junction was hereby occasionally exposed and the mucosal barrier became established to the fixture portion of the implant. It was suggested that the observed differences were the result of varying adhesive properties of the materials studied or by variations in their resistance to corrosion.     

A modified occlusal registration and implant transfer technique

The technique for the transfer of implant and abutment position to a working cast has been hindered by multiple transfers and record reproductions. These serve only to delay completion of the patient's prosthetic requirements. A transfer technique that uses custom impression trays fabricated from surgical templates allows for a single-visit transfer of centric occlusion, vertical dimension, tooth position, and implant or abutment location in one procedure. This streamlines treatment and allows for quicker delivery of final prostheses.     

A general dentist's guide to proper dental implant placement from an oral surgeon's perspective

This article is designed to help the general or restorative dentist more accurately predict proper implant placement by using palatal stents for the maxilla and lingual stents for the mandible, as well as parallel pin guides and vacupress stents, which help ensure both precise location and angulation. Because these stents and pin guides are easily used during surgery, the restorative dentist can prescribe with accuracy the exact position where the implants should be placed. To further the predictability of implant placement, especially in the anterior maxilla, an abutment can actually be placed into the pilot hole in the bone and checked with a vacupress stent before making the implant socket.     

Mechanical considerations for the implant tooth-supported fixed partial denture

The implant tooth-supported fixed partial denture presents a biomechanical design problem, because the implant is rigidly fixed within the alveolus, and the tooth is surrounded by a periodontal ligament that allows movement. Nonrigid fixed partial denture designs are advocated by some dentists as a method of compensating for this differential movement. Rigid fixed partial denture designs, however, are advocated by many clinicians. Studies have failed to show the advantage of one design over the other. This study developed an in vitro method for testing such prosthesis designs and measured movement of a natural tooth abutment during simulated function. The movement of the natural tooth abutment was not found to change substantially with the fixed partial denture designs tested.     

Speed temporaries, anterior and posterior

Several laboratories have stopped accepting implant cases because of the technical demands and the additional labor time required to process them. This article will discuss the IMPAC PDQ abutment (Vident, Brea CA). This abutment offers technicians a simple, reliable method for producing a strong, high quality implant substructure ready for porcelain application in a matter of minutes.     

Restoring the single lower incisor implant with esthetics, antirotation, and retrievability

The long-term success of restoring the lower incisor implant is partially dependent on retrievability of all components down to the implant. Because this implant is usually placed vertically or buccally in the bone, the ability to achieve esthetics without seeing the screw access hole becomes critical. The emergence profile of the crown overlying the implant fixture ultimately dictates the esthetics. The single crown can also become loose during function and, therefore, antirotation of the abutment is imperative. The Octa-Hex Implant Restoration System presents an alternative method of achieving gingival seal with a titanium-alloy connector to the implant, emergence profile with a custom-fabricated casting on this connector, antirotation from intimate contact with implant indexing, and retrievability by a fixation screw and cementation. With the lower incisor, this system offers retrievability without the screw access hole affecting esthetics.     

Paradoxical response to photorefractive treatment for postkeratoplasty astigmatism

Traditionally, the procedure of implant placement requires a surgical periosteal flap to be raised. In a percentage of implant cases, there is no need for flap surgery for implant placement, or for a follow-up surgical procedure for abutment connection. In this clinical investigation, 20 maxillary and mandibular implants were placed in seven adult male patients. The sites for implant placement were prepared according to an alternative surgical technique without raising a surgical flap. Patients were recalled periodically for 2 years to evaluate healing and clinical integration of implants. The results showed normal clinical healing at the first week of reexamination in all implant sites; periodontal probing of less than 2 mm circumferentially around all healing caps at 3 months and later at subsequent recall periods; no radiolucency observed in the peri-implant zone; no sign of clinical mobility during recall examination; and no persistent or irreversible sign or symptoms of pain, infection, or necrosis. This alternative surgical technique can provide several advantages over the traditional 2-step procedure.     

Histological evaluation of bone reactions to aluminium oxide dental implants in man: a case report

Alumina implants have been shown to possess high biocompatibility. The authors present the case of an aluminium oxide ceramic implant removed because of fracture of the abutment after a 30-month loading period. It was possible to observe microscopically that the implant was covered by highly mineralized mature compact lamellar bone; no connective tissue or inflammatory cells were present at the interface. Osteocytes were observed very close to the bone-implant interface. These features indicate the good biocompatibility of the implant.     

Schnitzler''s syndrome

OBJECTIVE: The surface roughness caused by four implant scalers (Premier/Hawe-Neos, Advanced Implant Technologies, Hu-Friedy, and Nobel Biocare) on a titanium abutment was assessed in a standardized in vitro situation, and operators were asked to evaluate the clinical usefulness of each instrument. METHOD AND MATERIALS: Twenty-four evaluators scored scanning electron micrographs of abutment surfaces scaled for 15 minutes with each instrument. Twelve operators used each instrument on at least three implant recall patients and scored each for ease of access; efficacy in deposit removal; overall convenience; distance reached subgingivally; scaling time per abutment; and overall preference. RESULTS: The Advanced Implant Technologies scaler created a significantly rougher surface than all other instruments. The Premier/Hawe-Neos and Advanced Implant Technologies instruments were significantly preferred in most categories by the operators. There was no statistically significant difference in scaling time per abutment. CONCLUSION: The Premier/Hawe-Neos instrument combines operator acceptance with less damage to the abutments, and, of the instruments tested, is the scaler of choice.     

The Orthosystem--a new implant system for orthodontic anchorage in the palate

The present report describes the design and first clinical experiences of a newly developed endosseous orthodontic implant anchor system (Orthosystem, Institut Straumann, Waldenburg, Switzerland) for palatal anchorage. The 1-piece fixture made of titanium consists of a screw-type endosseous implant body (sandblasted, acid-etched, diameter 3.3 mm, lengths: 4 and 6 mm), a cylindrical polished transmucosal neck and an abutment. Clamp-caps provide attachment of square commercially available orthodontic wires (0.032 x 0.032 inch, SS) to the abutment (transpalatal bars). In a pilot study 1 fixture (implant body length: 6 mm) was inserted into the midsagittal anterior palatal region in each of 6 adult patients with Angle class II malocclusion (distocclusion 7 to 8 mm, overjet: approximately 9 mm). The treatment plan included extraction of the first maxillary premolars and retraction of the anterior teeth based on maximum anchorage of the posterior teeth without using compliance-dependent anchorage aids (headgear, class II elastics). Due to the design of the fixture only 1 simple surgical procedure was required for insertion (nonsubmerged method, 1-stage surgery). Accordingly the need for surgical exposure of the abutment for connection and wire insertion was eliminated. Thus, inconvenience to patients was reduced to a minimum. The patients are now at varying active treatment stages. The course of treatment of the most advanced case is described. Evaluation of the clinical and radiological findings after 12 months of treatment (3 months implant healing, 9 months active orthodontic treatment which is equal to the implant loading period) revealed no implant mobility/dislocation, favourable peri-implant soft tissue conditions, no marked mesial movement (approximately 0.5 mm) of the implant/transpalatal bar supported posterior teeth, and 8 mm retraction of the anterior teeth. Retrieval of the fixture and post-operative wound healing were uncomplicated. In the treatment of this case, no compliance-dependent extraoral anchorage was used, and the well aligned mandibular dentition was not bonded provide anchorage support (class II elastics).     

My workplace: head nurse surgical department, Kongsvinger Hospital. A hazardous position. Interview by Kjell Arne Bakke

A method for making transplants for repair of abutment tissue defects and deformations based on computer technology is proposed. The technology unites surgical treatment, clinical and x-ray computer-aided diagnosis, computer processing of information and models, experiments, and production. Correspondence of the implant to repaired structures, site of implantation, and individual defect was confirmed experimentally [5], clinically [10], and by control computer-aided tomography. For the first time an implant was made by computer technology, identical to abutment tissue defect, and a method for plastic repair of defects and deformations in the skull by individually prepared implants developed and realized under clinical conditions.     

Biomechanical considerations when combining tooth-supported and implant-supported prostheses

The force distribution of multiple tooth-supported and implant-supported prostheses is completely different. A direct correlation exists between the degree of flexion at the site of loading and the amount of force distribution to other members of the prosthesis. Micromovement produced by the periodontal fibers facilitates force distribution to all the root surfaces of the natural tooth abutments. The rigidity of the implant/abutment/prosthesis configuration concentrates the force at the crestal bone at the site of loading with limited distribution to the remaining implants. Differential mobility concentrates the force distribution to the bone support of the most rigid members of splinted natural teeth or to the implants when they are united with natural teeth in a combined prosthesis. Implants always support the natural teeth and never the other way around. Therefore a nonrigid attachment is recommended between a tooth-supported prosthesis and an implant-supported prosthesis when they are combined. However, when implants are interspersed with natural teeth in the same prosthesis, the restoration will be implant borne. This requires special force distribution analysis to prevent implant overload.     

Implant reconstruction of the jaws and craniofacial skeleton

Full oral rehabilitation with a high degree of success is now possible with osseointegrated implants. Osseointegration is a direct connection between living bone and the titanium implant at the level of the light microscope. Osseointegrated implants are currently used to replace single teeth, support fixed bridges and stabilize full dentures. These implants can also be placed extraorally for attachment of facial prosthesis. The surgical technique used to place implants intraorally into jaws or facial skeleton is performed in two stages using a local anesthetic and/or conscious sedation. During stage I surgery, holes are placed into the jaw using a series of gradually larger diameter burs until the desired diameter and depth of the bony preparation is achieved. The implant is then placed. The implant must remain undisturbed for 4 months for osseointegration to take place. Stage II surgery is then required to remove the mucosa over the implant and place the transmucosal abutment. After 1-2 weeks of healing, the restorative dentist can take an impression and fabricate the prosthesis. On occasion, it is necessary to augment the height and width of the atrophic jaw with autogenous or allogeneic bone grafts prior to implant placement. Bone grafts are sometimes placed on the floor of the nose or the floor of the maxillary sinus. Guided tissue regeneration is a technique used to generate bone within bony defects adjacent to implants. With long-term rates of success (5 years) of 99% for implants placed in the mandible and 95% for those placed in the maxilla, reconstruction of the jaws and cranial facial skeleton with osseointegrated implants has become the treatment of choice.     

Study of mechanical properties of micromachined dental implants

Advancements in technologies and techniques within the dental industry have given rise to new and effective tooth replacement procedures for damages resulting from causes such as trauma or aging. While these treatments are widely available for patients, they remain highly expensive, preventing patients from much-needed dental care. The elevated cost of dental implants is in part associated with their components that are mainly available through third-party companies at a premium cost. To be cost effective, dental laboratories are exploring the option of producing their own dental implant components, and are therefore acquiring knowledge of manufacturing techniques and quality assurance expertise to produce quality components. In order to ensure high quality and reliability, the fabricated components must be tested and benchmarked against current implants on the market. The present study examines the micro machining process of dental implants, specifically for the abutments and screws, and its impact on the mechanical properties of the components. To achieve this, dental implant abutment and screw prototypes were fabricated, experimentally tested, and compared. The impact of different machining processes on the mechanical properties of the implants was comparatively determined and analysed. The fabricated implant testing results show coherent mechanical properties displayed by good hardness, and material microstructures similar to market components, indicating a high level of prototype quality.