Dental implant surfaces after insertion in bone: an in vitro study in four commercial implant systems.

OBJECTIVES: Primary healing of dental implants is influenced by their surface morphology. However, little is known about any alterations in morphology during their insertion. Therefore, the aim of this study was to evaluate the surface morphology of four different implant systems, following their insertion in porcine jaw bones. METHODS: Four fresh porcine mandible specimens were used. Six new implants of four systems (Ankylos® 4.5 × 14 mm, Frialit Synchro® 4.5 × 15 mm, NobelReplace ® Tapered Groovy RP 4.3 × 13 mm, Straumann SLA® Bone Level 3.3 × 14 mm) were inserted, whereas one implant of each system served as a control. After their removal, implants were cleaned in an ultrasonic bath. All 28 implants were examined quantitatively by 3D confocal microscopy for surface characteristics. RESULTS: In the evaluated zones, implants of the Ankylos, Frialit, and Straumann systems showed mostly a reduction of the mean surface roughness Sa, the maximal surface roughness Sz, and the developed surface area ratio Sdr; Nobel implants showed an increase in these parameters. With respect to all three parameters Sa, Sz, and Sdr, statistical analysis revealed that differences between the four systems were highly significant in the apical region of implants. Controls showed no morphologic alterations. CONCLUSION: The insertion process had an impact on the surface of all four implant systems. Anodized implant surface modification seems to result in more alterations compared with subtractive surface modifications. Therefore, surgical planning should take into consideration the choice of surface treatment because the characteristics of the implants may be modified during the installation process. CLINICAL RELEVANCE: The given information is of value for daily implantation practice and the course of osseointegration.

Toxicity of platinum, palladium and rhodium to Daphnia magna in single and binary metal exposure experiments.

Mainly due to automobile traffic, but also due to other sources, the platinum group elements (PGE) platinum (Pt), palladium (Pd) and rhodium (Rh) are introduced into aquatic biotopes where they accumulate in sediments of lakes and rivers. However, the toxicity of these noble metals to aquatic organisms is not well understood and especially toxicity studies under standardized condition are lacking. Thus, the toxicity of Pt, Pd and Rh to Daphnia magna was tested in single metal exposure experiments according to OECD guideline 202. Immobility and lethality was recorded after 24 h and 48 h of exposure and EC50 and LC50, respectively, were determined. As the nominal exposure concentration of Pd differed significantly from the quantified concentration, the control of the real exposure concentration by chemical analysis is mandatory, especially for Pd. The toxicity decreased in the order Pd > Pt â‰« Rh with e.g. LC50(48 h) values of 14 µg/L for Pd, 157 µg/L for Pt and 56,800 µg/L for Rh. The exposure period had a clear effect on the toxicity of Pt, Pd and Rh. For Pt and Rh the endpoint immobility was more sensitive than the endpoint lethality whereas Pd toxicity was similar for both endpoints. The Hill slopes, which are a measure for the steepness of the concentration-response curves, showed no significant discrepancies between the different metals. The binary metal exposure to Pt and Pd revealed a more-than-additive, i.e. a synergistic toxicity using the toxic unit approach. The present study is a start to understand the toxicity of interacting PGE. The modes of action behind the synergistic effect are unclear.

Do CBCT scans alter surgical treatment plans? Comparison of preoperative surgical diagnosis using panoramic versus cone-beam CT images.

Cone beam CT and/or panoramic images are often required for a successful diagnosis in oral and maxillofacial surgery. The aim of this study was to evaluate if 3D diagnostic imaging information had a significant impact on the decision process in six different classes of surgical indications. MATERIAL AND METHODS: Records of all patients who had undergone both panoramic X-ray and CBCT imaging due to surgical indications between January 2008 and December 2012 were examined retrospectively. In February 2013, all surgically relevant diagnoses of both conventional panoramic radiographs and CBCT scans were retrieved from the patient's charts. It was recorded whether (1) 3D imaging presented additional surgically relevant information and (2) if the final decision of surgical therapy had been based on 2D or 3D imaging. RESULTS: A total of 253 consecutive patients with both panoramic radiographs and CBCT analysis were eligible for the study. 3D imaging provided significantly more surgically relevant information in cases of implant dentistry, maxillary sinus diagnosis and in oral and maxillofacial traumatology. However, surgical strategies had not been influenced to any significant extent by 3D imaging. CONCLUSION: Within the limitations of this study it may be concluded that CBCT imaging results in significantly more surgically relevant information in implant dentistry, maxillary sinus diagnosis and in cases of oral and maxillofacial trauma. However, 3D imaging information did not alter significantly the surgical plan that was based on 2D panoramic radiography. Further studies are necessary to define indications for CBCT in detail.