What's New in Dentistry

Immediate loading of dental implants does not compromise success. Implants have revolutionized the restoration of patients with missing teeth. When they were introduced to dentistry in the early 1980s, the standard technique involved placing the implant and allowing it to integrate with the bone for 4 to 6 months before placing a restoration and providing an occlusal load on the implant. It was believed that this quiescent integration phase was critical to the long-term success of the implant. However, in recent years clinicians have challenged this delayed loading hypothesis, and have suggested that implants can be loaded immediately. A study published in the International Journal of Maxillofacial Implants (2005;20:99– 107) evaluates the results of early loading in a large sample of subjects. Over 250 patients took part in this study. A total of 700 implants were placed in these individuals. All implants were from the same manufacturer in order to reduce the variability of the experiment. The sample was divided into three groups. In one group, the implants were inserted into the alveolus and a restoration that occluded with the opposite arch was placed the same day. In the second group, implants were placed and restored on the same day, but the restoration was not allowed to occlude with the opposite arch. In the third group, the implant was buried, allowed to integrate, and restored thereafter. Then the surrounding bone level and implant mobility of all three groups were evaluated after 24 months. The results showed that early loading did not compromise the success of the implants. In each of the three study groups, only two implants failed. For all of the remaining implants, from a radiographic and clinical perspective, integration of the implant was successful. This convincing study suggests that immediate functional loading can provide satisfactory implant success rates in selected cases.

Fluoride tablets are beneficial for elderly individuals. The number of elderly people with teeth in the United States is increasing annually. In some, of these older individuals, proper oral hygiene becomes a challenge and dental decay can become a threat to the longevity of the teeth in our aging population. In order to reduce the risk of dental decay in this older age group, researchers have explored the possibility of using fluoride as an adjunct to oral hygiene. But how should the fluoride be delivered to the teeth? A study published in Acta Odontologica Scandinavica (2005; 63:65–72), evaluated the use of fluoride tablets as a means of delivering the fluoride effect to caries risk areas in the mouths of elderly subjects. Six healthy males between the ages of 60 and 70 years participated in this study. All participants were completely dentate and had a high number of restored teeth. One of the individuals had a history of active carious lesions in recent years. The subjects were asked to either place the fluoride tablet under their tongue or in the buccal vestibule near the cervical areas of the posterior teeth, which have a high risk for developing caries. Then these researchers measured the levels of fluoride in the saliva and in the plaque of each participant, to determine how long the fluoride remained in the oral cavity. The results of this study showed that the best place for elderly subjects to place the fluoride tablet was in the vestibule. In this location, high concentrations of fluoride were found in the cervical plaque on the posterior teeth as well as in the subjects' saliva. However, the fluoride effect decreased with time. Most of the fluoride in the plaque had been lost after five hours in the high-risk cervical areas, whereas in the non-risk areas on the teeth, it was largely retained. This study has demonstrated that fluoride exposure to vestibular caries risk areas on posterior teeth can be strongly increased by placing fluoride tablets close to them. The relatively rapid loss of fluoride from plaque indicates that more than one daily treatment would be required for elderly caries risk subjects.

Bone morphogenetic protein preserves alveolar socket width after tooth extraction. When teeth are extracted due to caries, trauma, or periodontal disease, the alveolar width of the remaining tooth socket diminishes with time. If implants will be used to replace the extracted teeth, and the implants are not placed soon after extraction, the alveolar ridge may require secondary bone grafting or augmentation in order to place the implant. Anecdotal references in the surgical literature suggest that placing various materials into the extraction socket will help to preserve the alveolar width and avoid the need for bone grafting when the implant is placed. However, few if any studies exist that have adequately tested this hypothesis. Recently, an article appeared in the Journal of Periodontology (2005;76:605–613) that investigated the use of bone morphogenetic protein placed into extraction sockets, as a method of preserving alveolar width prior to implant placement. The sample for this study consisted of 80 patients who were scheduled to have teeth extracted in order to place dental implants. These subjects were randomly divided into three groups. In one group, bone morphogenetic protein was impregnated into a resorbable collagen sponge and placed in the extraction sockets. In the second group, the sponge was placed into the socket without the bone morphogenetic protein impregnation (placebo). In the third group, nothing was placed in the extraction sockets (control). The authors assessed each of the socket areas after four months to determine the amount of bone induction, the adequacy of the alveolar bone volume to support an endosseous dental implant, and the need for a secondary augmentation. The results of this study showed that the widths of the alveolar bone in the group treated with the bone morphogenetic protein were nearly twice as great compared to the control and placebo groups. In addition, the bone density and histology revealed no differences between the newly induced and native bone. The data from this randomized, placebo controlled multicenter clinical study demonstrate that the combination of bone morphogenetic protein and a commonly utilized collagen sponge had a striking effect on bone formation for placement of dental implants.

Stannous fluoride reduces bacteria around single-stage implants. In the past, most implants were submerged beneath the gingiva during the integration process. By closing the flap over the implants, the potential ingress of bacteria was prevented. However, these implants required a secondary surgical procedure to uncover the implant. In order to avoid the need for a second surgery, newer implant designs allow the implant to be placed in a single surgical procedure with a healing cap protruding into the oral cavity. Unfortunately, this exposes the implant site to the ingress of oral bacteria. In order to combat the bacteria, chlorhexidine is often prescribed as a bactericidal agent to prevent bacterial contamination during the healing of the tissue surrounding the implant. However, chlorhexidine stains teeth and has an unfavorable taste. A study published in the Journal of Periodontology (2005;76:334–3405), evaluated the use of an amine fluoride/stannous fluoride mouthwash as a substitute for chlorhexidine after implant placement. The sample for this study consisted of 33 patients aged 34 to 79 years of age who required placement of dental implants. After surgery, patients were given mouthwash containing either chlorhexidine or amine fluoride/stannous fluoride. Various clinical parameters were then recorded at implant placement, and at 3 and 12 months after surgery. The implant survival rate for both groups was very high. Compliance with the mouthwash was slightly higher for the fluoride mouthwash compared to the chlorhexidine. With time, the staining from the chlorhexidine was slightly greater than the fluoride-containing mouthwash. This study has shown that mouthwash containing amine fluoride/stannous fluoride combination can be used successfully after single-stage implant placement to help control the bacterial population during the implant healing process.

Implants placed in grafted maxillary sinuses are successful. The long-term success of endosseous implants depends on the maintenance of bone support. In the posterior portion of the maxilla, the maxillary sinuses often become pneumatized after tooth extraction. This reduces the amount of bone and the potential support for a posterior maxillary implant. However, bone grafting of maxillary sinuses became popular several years ago as a method for adding bone in the posterior maxillary quadrants. Until now, few long-term reports of implants functioning in grafted sinuses have been available. A study published in the International Journal of Oral and Maxillofacial Implants (2005;20:261–266), evaluated the amount of bone resorption that occurred around dental implants placed in grafted sinuses after up to four years. The sample for this study consisted of 18 subjects who had 26 sinus grafting procedures performed. In this patient population, 37 implants were placed in their grafted maxillae. After four years, the change in marginal bone level around the implants at the mesial side was 1 millimeter during the first year after the abutment connection, followed by an annual loss of 0.1 millimeter. The change in marginal bone level around the implants at the distal side was 1.1 millimeter during the first year, flowed by an annual loss of 0.2 millimeter. In conclusion, the authors believe that their study suggests that bone grafting of sinuses is predictable. Their results showed low resorption in the medium term and provided optimal primary stability to the implants placed in their limited patient population.