Peri-implant bone reactions to immediately loaded implants. An experimental study in monkeys.

BACKGROUND: There are reports which demonstrate that immediately loaded splinted implants can be osseointegrated when they are placed in the anterior part of the lower jaw. The concept of immediate loading has not been well investigated in the posterior mandible. The aim of this study was to evaluate the bone reactions around immediately loaded implants placed in the posterior region of the lower jaw in the monkey model. METHODS: Six adult Macaca fascicularis monkeys were used in this study. A total of 36 implants were placed after extraction of the second premolars, first and second molars, and complete healing of the sockets. Three control (C) group implants were placed in one quadrant of the lower jaw of each monkey. After a delay of 3 months to allow osseointegration to take place, the implants were loaded for 1 month using temporary resin bridges and later for 2 months using metal splinted crowns. In the contralateral region of the lower jaw, 3 test (T) group implants were placed and loaded immediately with the same sequence as carried out for the C implants. Specimens were examined and evaluated histologically after sacrifice. RESULTS: All of the implants were osseointegrated. Compact, cortical bone in contact with the implant surface without any gaps or connective tissue formation was observed. CONCLUSIONS: It was concluded that immediately loaded, splinted implants can be osseointegrated with a similar hard and soft tissue peri-implant response as delayed-loaded implants in the posterior mandible.

Effects of diode and Nd:YAG laser irradiation on titanium discs: a scanning electron microscope examination.

BACKGROUND: Dental lasers have been recommended for uncovering submerged implants as well as decontaminating implant surfaces when treating peri-implantitis. The aim of this study was to show the possible alterations in titanium disc surfaces using an Nd:YAG or a diode laser. METHODS: Three different titanium discs were used (sandblasted, titanium plasma-sprayed [TPS], and hydroxyapatite [HA] coated) to determine the effects of laser irradiation on these surfaces using a scanning electron microscope (SEM). The discs were either irradiated with a pulsed Nd:YAG laser with a contact handpiece and power settings of 2.0, 4.0, and 6.0 W or with a diode laser at 5.0, 10.0, and 15.0 W power settings and continuous wave (cw) in the contact handpiece. Irradiated areas were compared with control titanium sites which were not lased. The specimens were prepared for SEM examination after the disc irradiation. RESULTS: The SEM examination demonstrated extensive melting in all of the Nd:YAG laser irradiated areas. Damage was seen in all TPS- and HA-coated discs even at the lowest power setting. Loss of porosity, coating microfractures, and a relatively smooth surface were observed. In contrast, the diode laser did not cause any damage or modify the disc surface. Regardless of the power setting, there was no visible difference between lased and non-lased surfaces after cw irradiation with the diode laser. CONCLUSIONS: From these findings, it was concluded that the diode laser (980 nm) does not damage titanium surfaces, which should be of value when uncovering submerged implants and treating peri-implantitis.

Single molar replacement with a progressive thread design implant system: a retrospective clinical report.

Many clinical studies have shown that replacement of molars with only 1 implant is commonly associated with various functional complications, such as implant fracture and screw loosening. Thus, multiple implants have been recommended to withstand the high occlusal forces present in the molar region. The aim of this retrospective study was to evaluate the clinical response to the use of single implants with a progressive thread design (Ankylos) in the replacement of molar teeth. Fifty-eight implants (10 in the maxilla and 48 in the mandible) were placed in 51 patients. The implants were in situ for 29.30 +/- 16.52 months and in function for 20.60 +/- 16.64 months. All crowns were cemented to the abutments. The crown occlusion was adjusted to obtain minimal normal contacts in the centric occlusion and eccentric positions. Implants were clinically and radiographically evaluated, and clinical indices (Plaque Index, Sulcus Bleeding Index, probing pocket depth, keratinized mucosa width, Perio-test) were recorded immediately before the placement of the prosthesis and once annually. Vertical and horizontal bone loss were also examined radiographically. Two implants were lost (1 because of fracture in a patient who was a bruxer and another because of abutment fracture in the endosseous part of the implant). All clinical and radiographic parameters of most of the implants were comparable to the values found for the same type of implant in other clinical indications. The reduced incidence of failure (96.55% survival rate) found in this study with the Ankylos implant system compared to the results reported in the literature indicate that this system can be used for the replacement of molars using single-implant-supported restorations.

Diode laser (980 nm) in oral and maxillofacial surgical procedures: clinical observations based on clinical applications.

OBJECTIVE: The aim of this study was to examine the wound healing of soft tissue after the application of a diode laser (980 nm) in oral surgical procedures. SUMMARY BACKGROUND DATA: Like the CO2 laser, the diode laser can be used for soft tissue surgery without extensive experience in the field of oral surgical. METHODS: A diode laser was used to treat a variety of oral soft tissue lesions in 22 patients. The oral surgical procedures included removal of soft tissue tumors, frenectomies, excision of gingival hyperplasias, vestibuloplasties, hemangioma removal, and periimplant soft tissue surgery. The laser was used in both pulsed and continuous modes, with and without contact to the tissue. Intraoperative and postoperative clinical observations are reported. RESULTS: Our preliminary clinical findings include sufficient hemostasis and precise incision margin with all of the surgical procedures. The coagulation properties, associated with the use of a diode laser, were particularly beneficial during removal of vascular lesions. The postoperative advantages, i.e., lack of swelling, bleeding, pain or, scar tissue formation, and the good wound healing were observed in all of the clinical applications and were dependent only on the laser physical parameters used. CONCLUSIONS: The clinical application of the diode (980 nm) laser in oral and maxillofacial surgical procedures seems to be of beneficial effect for daily practice.

Application of automated thermal disinfection instead of sterilisation procedures for treatment of rotating dental instruments: efficacy against viruses?

In dentistry it is of primary importance to take into consideration microbial transfer due to the nature of the construction of rotating dental instruments. This aspect was the starting point for our research with the question whether or not sterilisation is fundamentally necessary for slow and high speed hand pieces to make them "safe" out of a virological point of view, or whether a thermal disinfection could also possibly be adequate for this purpose. In this context, we tested the efficiency of the cleaning and disinfection capacity of an automated steam disinfection and sterilisation unit (Sirona Hygiene Center, Siemens, AG, Bensheim) intended to the hygienic treatment of dental instruments with respect to viruses. In model tests the corresponding instruments were experimentally infected with herpes simplex virus type 1 (HSV) and simian vacuoling virus (SV40). As indicator systems we used for both cell cultures (measurement of the degree of infectiosity) and (for HSV) polymerase chain reactions (PCR; determination of viral nucleic acids). In the tests for (residual) infectiosity after thermal disinfection (as an isolated step of the Hygienic Centre) and also for a combination of cleaning and subsequent thermal disinfection (also after protein application), no infectious virus could be found in the interior of the slow handpieces and turbines tested. In opposite to this, infectious HSV and SV40 could be found after completion of every isolated cleaning program in the turbine (in all three ducts) and in the slow handpiece (only in the gearbox duct in the case of HSV, and in the case of SV40 also in the water and air ducts in very small amounts). The PCR analyses showed that no nucleic acids could be found in both instruments (in the air and water ducts) following a practice-relevant combination of cleaning and disinfection, but that PCR-positive signals were obtained for the larger-volume gearbox and drive and return air ducts in 1 or 2 of 3 test samples. The detection of viral nucleic acid proves that it is not a matter of complete removal of the infectious agents from the instruments, but rather that they are simply inactivated. Since the test samples did not show similar amounts of viral nucleic acid, it demonstrates the strong influence of the basic parameters (efficiency of the virus contamination, flushing conditions and the like). Our experimental model demonstrate that thermal disinfection may be adequate to prevent virus contamination of rotating dental instruments, while compulsory sterilisation is not mandatory. Further studies are necessary to demonstrate whether the present data are applicable for rotating dental instruments from other manufactures.

[The therapy of the postextraction syndrome with Taurolin. A controlled clinical study]. / Die Therapie des Postextraktionssyndroms mit Taurolin. Eine kontrollierte klinische Studie.

In a controlled clinical study with a total of 200 patients the broad spectrum agent and antitoxin taurolidine (Taurolin) was clearly superior to conventional medication with the broad spectrum antibiotic chlortetracycline (Aureomycin) when applied topically to treat the postextraction syndrome. Thus, the mean duration of therapy (primary target criterion) with Taurolin (group A) was 5.6 days compared to 8.2 days with the standard therapy (group B). In statistical terms this difference was highly significant (p < 0.0001). Compared with the conventionally treated patient group, the clinical control parameters such as pain, swelling, secretion, tenderness to pressure and remission (secondary target criteria) in the Taurolin group exhibited not only a markedly more rapid normalisation of the score-data during the initial phase, but also an appreciably shorter interval until the patients were symptom-free. Age, gender, localisation of the lesion or facultative systemic antibiotic or analgetic administration had no demonstrable effect on the course of the treatment, although the patients in the reference group required concomitant medication with antibiotics (p = 0.007) and analgetics (p = 0.01) considerably more often than those in the Taurolin group.

[Comparison of treatment results after collum fractures in children and adolescents]. / Vergleich der Behandlungsergebnisse nach Kollumfrakturen bei Kindern und Jugenlichen.

52 patients aged between 5 and 19 years with a total of 68 collum fractures were examined in a clinical, radiological and sirognathographical follow-up study. Except for the luxation fractures of the upper collum there was no significant difference in the results of immobilisation therapy (77%) and functional therapy. Only in the case of collum luxation fractures were our X-ray findings less positive. Patients under the age of 15 showed a better tendency for restitution.

[Survival rate of desmodontal cells in relation to their extraoral dehydration]. / Uberlebensrate desmodontaler Zellen in Abhängigkeit von der extraoralen Austrocknung.

The success of tooth replantation following traumatic avulsion depends to a large degree on the vitality of periodontal ligament cells which remain on the root surface. Loss of vitality promotes root resorption. In this study 124 freshly extracted teeth, only front teeth and premolars, were stored in dry environment for periods of 10 to 150 min. The vitality of the residual periodontal ligament tissue was tested by means of the fluorescein-diacetate reaction. The root area covered by vital tissue decreased to 90% after 30 min and to 70% after 45 min of dry storage. Between 60 and 90 min after extraction the vital tissue area decreased rapidly to about 10%.