Quintessence International, 06/2004

Things are getting rougher out there. Or smoother, depending on where you started. We're talking implant surfaces here. When we first began using osseointegrated implants, it was like the Model A Ford. You could choose any color you wanted, as long as it was black. In our case, you could have any surface you wanted, as long as it was machined. This surface, now called turned by my more erudite colleagues, was produced when screw threads were milled on a blank titanium rod. When the corporate world caught up with Professor Brånemark, they started making modifications to his original design. In my opinion, he should have too; but that is another story. The result was a panoply of surfaces ranging from smooth to rough and everything in between. While all these surfaces established an intimate relationship with the bone, some did so to a greater degree than others. In addition, some surfaces underwent great scientific scrutiny before coming to market; some were just produced in the inventor's garage and sold the next day. To understate, this led to confusion and to the beginnings of the implant wars. These wars continue today. But science intervened. I will never forget seeing the first SEM of what was assumed to be an osteoblast laying across a machined surface looking to all the world, like a fried egg. This was the beginning, along with torque removal tests, percentage of bone-to-implant contact, etc, of a great debate that we all see and read about today. As I understand it, the happier the osteoblast, the more bone it produces, and the fried egg model does not represent a happy osteoblast. They tell me that these cells need to stand up on their own little legs (pseudopodia to the academic types) before they can really turn out the bone we surgeons love, and turn it out faster so we can get the crowns on those implants faster and make the referring dentists and the patients happier more quickly. Again, as legend has it, you need certain surface characteristics to allow this to occur with the rapidity that we all are seeking. The result of this desire to load faster was the great surface battle. This battle was fought primarily by the companies and their designated surrogates (remember yours truly is occasionally one of those hired guns-see my May 2001 editorial). We all went out and shot at each other for years; the fact that we had little ammunition did not deter us one whit. But slowly the tide changed. Science started to come to the fore, and a group of surfaces that osteoblasts like to stand up on were discovered. This improved torque tests and bone-to-implant contact percentages. And what have we found so far regarding the optimal surface? That this surface is somewhere between two extremes. Not overly smooth or overly rough. So now all the large manufacturers feature some type (or many types) of rough surface. The war continues, but the combatants have reached a general agreement in the surface battle. Gosh, that was hard. Thomas G. Wilson, DDS Editor-in-Chief

A major disadvantage in using the forced eruption technique is the necessity for the placement of an unesthetic orthodontic appliance, especially when the tooth involved is a maxillary incisor. The aim of this article is to present two alternative simple, specific task-oriented devices that may be placed on the lingual side of the teeth and may be used in the anterior of the mouth without compromising appearance.

Objective: The dental literature has been unclear about long-term success of fixed cantilever prostheses supported by dental implants. The disappointing results reported when cantilever fixed partial dentures (FPDs) are supported with natural teeth are not directly applicable to implant cantilever FPDs. This article reports on 10 years of implant-retained fixed prostheses primarily in the maxillary arch using the ITI dental implant system. Method and materials: Sixty cantilever prostheses using 115 ITI dental implants on 36 patients were placed and monitored over a 10-year period. Results: No implant fractures, abutment fractures, porcelain fractures, prosthesis fractures, soft tissue recession, or radiographic bone loss were recorded. All 60 cantilevered prostheses remain in satisfactory function. Conclusion: Positive, long-term results, using implant-retained cantilever FPDs can be achieved by: (1) using a rough surface implant of 4.1 mm or greater; (2) using an implant/abutment design that reduces stacked moving parts and reduces the implant-to-crowns ratio; and (3) using a cementable prosthesis design that eliminates the need for occlusal screw retention.

Objectives: This study aimed to evaluate the retention on two or four implants of eight resilient and nonresilient retentive anchors used in overdentures. Method and materials: Eight groups of retentive anchors were used: Dyna and Shiner (magnets); Dalla Bona and O-Ring (balls); Ceka Revax and Zaag attachments (studs); the cast bar (Dolder type) system with plastic clips; and the milled bars system. These specimens with their respective overdentures were prepared on two similar acrylic resin models with four implants (3.75 × 13 mm). Ten tensile strength tests (Instron) were performed on each group at a speed of 3 mm per minute. The statistical analysis (one-way analysis of variance, Tukey's HSD test) was considered significant. Results: The pull force values ranged between 0.400 and 3.800 daN (International System of Units). There was a significant difference in retention in favor of the milled bars in comparison with the Ceka Revax, Hader bars, Zaag attachments, O-Ring, and Dyna groups, and a marginally significant difference compared with the Dalla Bona group. There was a highly significant difference with the Shiner magnets. Conclusion: The milled bar system was the most retentive anchor, with the Dalla Bona, Ceka Revax, Hader Bar, Zaag attachment, and O-Ring groups being the second most retentive. The least retentive groups were the Shiner and Dyna magnets. Proper abutment placement in the mandible and the correct selection of the retentive anchor will improve overdenture retention.

Objective: The purpose of this study was to develop and adapt a new method for testing dental implant systems and to apply it to existing systems with and without dampers. The parameters examined were the fatigue strength of the superstructure-retaining titanium screw, the deformation of the damper, and the effect on the supporting, bone-stimulating, and embedding material. Method and materials: Ten pairs of implant specimens were prepared according to standard laboratory procedure and embedded in transparent polymethylmethacrylate (PMMA). Five pairs were provided with polyoxymethylene dampers and five with nondamping titanium connectors. Each pair was connected with a metal beam, and cyclic loads were applied with a pneumatic-driven machine at a frequency of 2 Hz. Chewing forces of 150 to 450 N were transmitted by springs individual to each specimen. For each of the 2 × 10⁵ cycles, there was a control of the retaining screw and bonding between the fixture and embedding material by registration of gap propagation in the implant-PMMA interface. Results: A significant damping effect was noticed on the implant -embedding material interface. Damping did affect the superstructure, since the retaining screws were plastically deformed. The screws were unscrewed when the applied load exceeded 300 N, while the undamped system was seemingly unaffected. Conclusion: The study method made it possible to evaluate damping effects on different levels of implant systems, while satisfying the requirements for testing in a "clinical-like" way. PMMA was comparable to bone in supporting implants during fatigue testing.

Patient demand for esthetics has increased globally, and often for reasons of patient self-esteem. However, important ethical issues encompass treatment for purely esthetic reasons. Also, perceptions of what is esthetic differ among patients and clinicians. Therefore, the aim of this article is to make suggestions regarding some of the issues surrounding the ethical, esthetic treatment of patients, as well as present three cases illustrating the different meanings of esthetic health to different people.

Objectives: The purpose of this study was to determine the effect of three cavity disinfectants (chlorhexidine gluconate-based, Consepsis; benzalkonium chlorite-based, Tubulicid red; iodine-potassium iodide/ copper sulphate-based, Ora-5) on the microleakage of nonrinsing dentin-bonding systems, Clearfil SE Bond and Prompt L-Pop. Method and materials: Class V cavity preparations were placed on the buccal and lingual surfaces of extracted molars with occlusal margins at the enamel and gingival margins in cementum. In the experimental groups, cavities were treated with combinations of one of the three cavity disinfectants with either Clearfil SE Bond or Prompt L-Pop. The preparations without disinfectant application were used as the negative controls for each adhesive system, and the cavities in which neither disinfectant nor dentin-bonding resin were applied, served as the positive controls. After the cavity preparations were restored with resin composite, specimens were thermocycled, stained, and sectioned to evaluate dye penetration. The tooth-resin composite interface of the sectioned specimens was examined under scanning electron microscopy. Results: Consepsis and Tubulicid red did not significantly affect the sealing ability of Clearfil SE Bond and Prompt L-Pop. Ora-5 exhibited gap formations at the tooth-resin composite interface and produced significantly higher microleakage when used with these bonding systems. Conclusion: Consepsis and Tubulicid red can be used as cavity disinfectants with Clearfil SE Bond and Prompt L-Pop without affecting their sealing abilities. However, Ora-5 is not an appropriate disinfectant to use with these bonding systems.

Objective: The maxillary (or second division) nerve block is an effective method of achieving profound anesthesia of a hemimaxilla. This block can be used for procedures involving the maxillary sinus, including the maxillary sinus elevation procedure. The purpose of this study was to evaluate a computer-controlled anesthetic delivery system (Wand) for maxillary nerve block injection to attain maxillary sinus anesthesia for sinus floor elevation procedure. Method and materials: The study population consisted of 61 healthy adult patients, ranging in age from 40 to 72 years (mean 45 years), who received 76 maxillary nerve blocks (17 having both right and left maxillary blocks) by means of the Wand system via the greater palatine nerve approach, for sinus floor elevation procedure. Two patients (3%) were excluded from the study due to the inability to negotiate the greater palatine foramen. For each block, two cartridges of 2% lidocaine hydrochloride with adrenaline (1:100,000) were administered, using a 27-gauge-long needle. After ensuring the anesthetized areas (waiting time 2.5 minutes), the sinus elevation procedure was performed. Parameters recorded were the success or failure of anesthesia, positive (blood) aspiration, bony obstructions in the greater palatine canal, and complications. Results: The use of this technique increased the ability to more easily locate the greater palatine foramen. A local infiltration (at the incisor region) was needed in 13 (17%) of the blocks, and seven (9.2%) sites required an extra infraorbital block injection in addition to the maxillary nerve block. One block had a positive aspiration. There were no bony obstructions demonstrated in the canal interfering with the injection, and no complications were recorded. Conclusion: The Wand appears to offer a number of advantages over the hand-held syringe when the greater palatine block technique for the maxillary nerve block is used. It is suggested that, when indicated, and with the required knowledge and respect for the associated anatomy, this technique should be considered with greater ease and more confidence.

The routine use of antibacterial agents for the management of odontogenic infections has not been shown to be effective and is inappropriate. Most of these bacterial infections can be resolved satisfactorily through an approach that incorporates debridement (primary dental care) in conjunction with local anesthesia. Odontogenic infections are polymicrobial. Facultative anaerobes, particularly viridans streptococci, accompanied by strict anaerobes, appear to predominate in all types of odontogenic infections. When antibacterial chemotherapy is indicated, the drug of choice should be either the most effective drug against the infective pathogens or the least toxic alternative among several available agents. It should also be emphasized that drugs seldom exert their beneficial effects without also causing adverse side effects. Dealing with this certainty, the clinician familiar with the mechanisms of action, principles of disposition, and therapeutic and adverse effects of antibacterial agents, has the advantage.