Inlay autograft of intra-membranous bone for lateral alveolar ridge augmentation: a new surgical technique.

This study describes a new surgical technique for harvesting intra-membranous bone from the mandibular symphyseal region and using it as an inlay graft. The surgical technique of turning a complex-shaped defect into a defect of defined size by contour preparation and insertion of an appropriate inlay graft was used in 31 patients. At 4 months, 15 patients (48%) showed negligible graft resorption of 0.33 mm. At 5-8 months the resorption rate in the remaining 16 patients was around 1.22 mm. All in all, a significant positive correlation was found between bone resorption and time (r = 0.574; P < 0.001). All patients received an implant after the fixation screw was removed. A conservative interpretation of the results suggests that, on account of the flush fit and the early revascularization of the graft, implants may and should, in fact, be inserted earlier in order to prevent graft resorption.

Short epithetic implants for orthodontic anchorage in the paramedian region of the palate. A clinical study.

Orthodontic movement of teeth often requires maximum anchorage, so that additional resistance must be added to teeth to avoid reaction to reciprocal forces. Thus, use of endosseous implants may be a valuable alternative for ensuring stable intraoral anchorage. This study was designed to evaluate the efficacy of short epithetic implants for orthodontic anchorage in the paramedian region of the palate. Twenty-one patients (15 female, 6 male; mean age 25.8+/-9.9 yrs, min 12.7, max. 48.1) were included in this study. Following adequate preoperative planning, an implant system with reduced length, which had already been used for anchorage of epitheses, was placed in the paramedian region avoiding the anterior palatine suture. After a mean period of 4 months with unloaded healing, the implants were subjected to direct or indirect orthodontic loading. Despite varying bone quality and varying vertical bone volume in this region, adequate primary stability was achieved for all of the implants. No implant was lost during the healing period. Three out of the 21 implants placed were considered as failures. Two implants loosened shortly after the start of orthodontic loading. One of these was lost at a later stage due to peri-implant inflammation, while the other one was left in place during the 9-month follow-up period because no inflammation developed and this implant is still indirectly included in the orthodontic treatment. Another implant loosening was observed after 8.5 months following direct loading with 8 N. This implant was also lost due to peri-implant inflammation. The time-related survival probability was 84.8% after 22.9 months. As yet, 4 implants have been removed due to completion of orthodontic treatment. The results of this study indicate that short epithetic implants are suitable to achieve maximum anchorage in the paramedian region of the hard palate in orthodontic treatment.

Lethal photosensitization for decontamination of implant surfaces in the treatment of peri-implantitis.

Peri-implantitis is considered to be a multifactorial process involving bacterial contamination of the implant surface. A previous study demonstrated that a combination of toluidine blue O (100 microgram/ml) and irradiation with a diode soft laser with a wavelength of 905 nm results in an elimination of Porphyromonas gingivalis (P. gingivalis), Prevotella intermedia (P. intermedia), and Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) on different implant surfaces (machined, plasma-flame-sprayed, etched, hydroxyapatite-coated). The aim of this study was to examine the laser effect in vivo. In 15 patients with IMZ implants who showed clinical and radiographic signs of peri-implantitis, toluidine blue O was applied to the implant surface for 1 min and the surface was then irradiated with a diode soft laser with a wavelength of 690 nm for 60 s. Bacterial samples were taken before and after application of the dye and after lasing. The cultures were evaluated semiquantitatively for A. actinomycetemcomitans, P. gingivalis, and P. intermedia. It was found that the combined treatment reduced the bacterial counts by 2 log steps on average. The application of TBO and laser resulted in a significant reduction (P<0.0001) of the initial values in all 3 groups of bacteria. Complete elimination of bacteria was not achieved.

Experimentally induced peri-implantitis: a review of different treatment methods described in the literature.

The aim of this article was to present the experimental peri-implantitis models described in the literature and to provide a review of currently used treatment methods. For this purpose, 29 English- and German-language studies published in internationally reviewed journals were examined for similarities and differences regarding animal models, types of implants, and methods used for inducing peri-implantitis. In almost all studies, the implants were located in the mandible, which suggests that peri-implantitis of the maxilla has been researched very little. While in most studies, peri-implantitis was induced by means of ligature and plaque accumulation, only 3 studies have been published that attempted to induce peri-implantitis by means of mechanical overload. Of the latter, only one author observed peri-implant bone resorption. Eleven studies reporting on ligature-induced peri-implantitis presented enough data to be subjected to further statistical data analyses. Meta-analysis revealed that the period of ligature application, and thus the duration of plaque accumulation, generally had no influence on the resultant depth of the bone defect. However, when screw-type and cylindric implants were analyzed separately, a weakly significant positive effect of the duration of ligature application on the resultant defect depth was determined for cylindric implants (P = .092). This could imply that smooth screw-type implants were less susceptible to ligature-induced peri-implant inflammation. Regenerative treatment methods included the membrane technique using non-resorbable membranes (guided bone regeneration), augmentation with autogenous bone, augmentation with bone substitute materials (hydroxyapatite or demineralized freeze-dried bone) or with recombinant human bone morphogenetic protein-2, and a combination of membrane and augmentation procedures. While all described methods resulted in acceptable bone gain, it seems to be difficult to achieve new osseointegration (reosseointegration) of treated implants. Of all tested treatment methods, the combination of guided bone regeneration and augmentation with demineralized freeze-dried bone resulted in the most favorable results regarding bone gain and reosseointegration.

[Influence of risk factor "hot foods over 37 degrees Celsius" on oral flora and the pathogenesis of gingivitis and periodontitis]. / Der Einfluss des Risikofaktors "Nahrung mit mehr als 37 degrees C" auf die Keimzahl der Mundhöhle und die Entstehung von entzündlichen Parodontopathien.

Austrian law prescribes that hot food and beverages must be served at a minimum temperature of 75 degrees C. Within a group of 50 volunteers, we studied hot food at a temperature higher than 37 degrees C as a risk factor for the pathogenesis of gingivitis and periodontitis. In the first part of the investigation the effects of heat on bacterial growth in the mouth were evaluated. Bacterial growth was significantly reduced after drinking hot tea (70 degrees C) (p < 0.001). The ability of the volunteers to estimate the temperature of a direct heat stimulus in the mouth was tested in the second part of the study. 82% of the volunteers underestimated the temperature of tea (70 degrees C) by about 15 degrees C. In the third part of the study the periodontal state of the volunteers was determined by index measurements. Moreover, eating behaviour was assessed by a questionnaire. No statistically significant correlation between eating behaviour (hot/cold) and periodontal inflammation was found.

Lethal photosensitization, autogenous bone, and e-PTFE membrane for the treatment of peri-implantitis: preliminary results.

This clinical study reports on the results of a new method in the treatment of peri-implantitis. The surfaces of 24 plasma flame-sprayed cylindric implants in 17 patients who were diagnosed with peri-implantitis were decontaminated with a combination of toluidine blue (100 micrograms/mL) and laser irradiation at a wavelength of 906 nm. Bone defects were filled with autogenous bone using e-PTFE membranes for retention of the grafting material. Premature membrane exposure occurred in all patients after an average of 3 weeks (+/- 10 days), which required immediate removal of the exposed membrane in 1 patient. Since the soft tissue showed minimal signs of inflammation, the membranes were left in situ for another 6 weeks in all other patients. The mean radiographic peri-implant bone gain was 2 mm +/- 1.90 mm after 9.5 months (maxilla 2.5 mm +/- 2.38 mm; mandible 1.9 mm +/- 1.87 mm). Two implants around which the initial bone defect had already reached the basket had to be removed after 10 months and 35 months, respectively, despite radiographic evidence of improvement of the peri-implant defect. The longer the membrane stayed in situ, the more bone was gained, as long as the membrane was covered by soft tissue (P = .01). However, the longer an exposed membrane was left in place, the smaller the resultant bone gain (P = .0001). Therefore, despite the absence of clinical signs of inflammation, exposed membranes should be removed immediately. The short-term results of this study corroborate the efficacy of the applied treatment method in prolonging the service time of dental implants involved with peri-implantitis.

Biostimulation of bone marrow cells with a diode soft laser.

In recent years, the use of low-intensity red light in regeneration of soft tissue has been increasingly pursued. As far as hard tissue is concerned, the biostimulating effect of laser has already been demonstrated successfully in more rapid healing of tibial bone fractures in mice at a dosage of 2.4 J. However, the effect of light of a low dose laser directly on osteoblasts has not been investigated yet. The aim of this study was to determine the effect of continuous wave diode laser irradiation on osteoblasts derived mesenchymal cells. Three groups of 10 cultures each were irradiated 3 times (days 3, 5, 7) with a pulsed diode soft laser with a wavelength of 690 nm for 60 s. Another 3 groups of 10 cultures each were used as control groups. A newly developed method employing the fluorescent antibiotic tetracycline was used to compare bone growth on these culture substrates after a period of 8, 12 and 16 days, respectively. It was found that all lased cultures demonstrated significantly more fluorescent bone deposits than the non-lased cultures. The difference was significant, as tested by the Tukey Test (P < 0.0001) in the cultures examined after 16 days. Hence it is concluded that irradiation with a pulsed diode soft laser has a biostimulating effect on osteoblasts in vitro, which might be used in osseointegration of dental implants.

Alternative to the median region of the palate for placement of an orthodontic implant.

Tooth-borne anchorage may be one of the greatest limitations of modern orthodontic treatment, because teeth move in response to forces. Previous investigators have placed temporary implants in the median-sagittal palate in order to establish maximum anchorage. This area, however, may be characterized by relatively low vertical bone support. The aim of this study was therefore to find an alternative palatal implant site which offers a higher amount of bone support. This study comprised 22 patients wishing for maximum anchorage underwent presurgical diagnostic evaluation by means of low-dose dental CT. The measuring results regarding vertical bone volume and the position of the neighbouring tooth roots were used as the basis for further treatment. The statistical data analysis indicated an area suitable for implant placement in the group of patients examined. This area was located 6 to 9 mm posterior to the incisive foramen and 3 to 6 mm paramedian, under avoidance of the mid-palatal suture. The patients showed such a great range of variation in vertical bone volume that a preoperative diagnostic evaluation also seems to be recommendable when very short implants are used in order to avoid perforations of the lower nasal duct.

Use of crestal bone for augmentation of extremely knife-edged alveolar ridges prior to implant placement: report of 3 cases.

A technique is presented for interforaminal lateral augmentation of mandibles with adequate bone height, but extremely knife-edged mandibular alveolar ridges (Class IV of Cawood and Howell's classification of residual ridges), in which the crestal portion of the knife-edged ridge is used as grafting material. Following an osteotomy and rotation of the grafts by 180 degrees, the grafts were fixed to the residual ridge below the osteotomy line by means of miniscrews. All grafts showed only mild resorption after a healing period of 3 months, and it was possible to place 4 implants in the now sufficiently wide host region.

Experimental study of the damping behaviour of IMZ implants.

Measurements of the damping behaviour of dental implants with the Periotest device are considered to be an objective means to assess the mobility of implants. The effects of the position of an implant in the maxilla or mandible, the period of time passing between the measurements and implant placement and the height at which the Periotest measurements are performed on the damping behaviour of implants have been discussed controversially. This experimental study examined the influence of the use of different measuring devices, the measuring height and the embedding depth on the damping behaviour of IMZ implants. The implants were embedded in resin at different depths and damping measurements were carried out at different measuring heights. It was found that the values rose with an increasing measuring height and a decreasing embedding depth. Analysis of variance was used to assess the influence of the embedding depth and revealed that the embedding depth had a significant impact on the measuring values at each measuring height, above 6 mm. Moreover, it was found that the higher the measuring height, the higher the measured values and the greater the differences between the values obtained at the individual depths. The different measuring devices had no influence on the measuring results (P = 0.79). The results of this study suggest that a longitudinal follow-up of the peri-implant residual bone height around individual implants is possible. Single measuring values by themselves do not allow any conclusions about the prognosis of an implant. The assessment of the peri-implant bone height through Periotest measurements is conceivable only when a table of damping values taking into account the physical length of the implant, the embedding depth and the measuring height for the examined implant system is available. In cylindrical implants, the head of the available prefabricated measuring post can be recommended as a constant measuring point for further studies, especially when the results are to be compared with those obtained by other study groups.

Bovine hydroxyapatite for maxillary sinus augmentation: analysis of interfacial bond strength of dental implants using pull-out tests.

This study examines the effect of sinus lift surgery using bovine hydroxyapatite on the bone anchorage of titanium plasma flame-spray-coated cylindrical implants. A total of 54 implants were placed in the lateral bony antral walls of 27 mountain sheep. Host site augmentation was done simultaneously using bovine hydroxyapatite and autogenous cancellous bone from the iliac crest in 18 sinuses each. The bone walls of the remaining 18 sinuses received no augmentation. Pull-out tests were carried out at 12, 16, and 26 weeks, revealing a significant influence of the implants' residence time on pull-out strength (P = 0.004). The implants of the non-augmented group and those of the group augmented using cancellous bone showed a linear increase in pull-out strength to 169.8 N and 523.7 N, respectively, until the 26th week. The implants of the group augmented with bovine hydroxyapatite exhibited the highest initial pull-out strength (325.1 N) that further increased to 521.8 N until the 26th week. All in all, this group showed a significantly greater pull-out strength tan did the negative control group (P = 0.03).

Elimination of bacteria on different implant surfaces through photosensitization and soft laser. An in vitro study.

Microbiologic examinations of implants have shown that certain microorganisms described as periodontal pathogens may have an influence on the development and the progression of peri-implant disease. This experimental study aimed to examine the bactericidal effect of irradiation with a soft laser on bacteria associated with peri-implantitis following exposure to a photosensitizing substance. Platelets made of commercially pure titanium, either with a machined surface or with a hydroxyapatite or plasma-flame-sprayed surface or with a corundum-blasted and etched surface, were incubated with a pure suspension of Actinobacillus actinomycetemcomitans or Porphyromonas gingivalis or Prevotella intermedia. The surfaces were then treated with a toluidine blue solution and irradiated with a diode soft laser with a wave length of 905 nm for 1 min. None of the smears obtained from the thus treated surfaces showed bacterial growth, whereas the smears obtained from surfaces that had been subjected to only one type of treatment showed unchanged growth of every target organism tested (P < 0.0006). Electron microscopic inspection of the thus treated platelets revealed that combined dye/laser treatment resulted in the destruction of bacterial cells. The present in vitro results indicate that lethal photosensitization may be of use for treatment of peri-implantitis.

In vitro testing of clarithromycin in combination with ethambutol and rifampicin against Mycobacterium avium complex.

The activity of clarithromycin in combination with ethambutol and rifampicin was tested at concentrations achievable in serum against 20 strains of Mycobacterium avium complex. The combination of clarithromycin plus rifampicin showed inhibition of 11 of the strains and bactericidal synergism against seven of the strains. When ethambutol was added, a bactericidal effect was observed against 16 strains. On the basis of these in vitro data it seems that clarithromycin in combination with rifampicin and ethambutol may be a promising drug for the effective treatment of infections caused by M. avium complex.