Accuracy of vertical height measurements on direct digital panoramic radiographs using posterior mandibular implants and metal balls as reference objects.

OBJECTIVES: Conventional panoramic radiography, a widely used radiographic examination tool in implant treatment planning, allows evaluation of the available bone height before inserting posterior mandibular implants. Image distortion and vertical magnification due to projection geometry is well described for rotational panoramic radiographs. To assess the accuracy of vertical height measurements on direct digital panoramic radiographs, implants and metal balls positioned in the posterior mandible were used as radio-opaque reference objects. The reproducibility of the measuring method was assessed by the inter- and intraobserver agreements. METHODS: Direct digital panoramic radiographs, performed using a Kodak 8000C (Eastman Kodak Company, Rochester, NY), of 17 partially edentulous patients (10 females, 7 males, mean age 65 years) were selected from an X-ray database gathered during routine clinical evaluation of implant sites. Proprietary software and a mouse-driven calliper were used to measure the radiological length of 25 implants and 18 metal reference balls, positioned in mandibular posterior segments. The distortion ratio (DR) was calculated by dividing the radiological implant length by the implant's real length and the radiological ball height by the ball's real height. RESULTS: Mean vertical DR was 0.99 for implants and 0.97 for balls, and was unrelated to mandibular sites, side, age, gender or observer. Inter- and intraobserver agreements were acceptable for both reference objects. CONCLUSIONS: Vertical measurements had acceptable accuracy and reproducibility when a software-based calibrated measurement tool was used, confirming that digital panoramic radiography can be reliably utilized to determine the pre-operative implant length in premolar and molar mandibular segments.

Titanium hydride and hydrogen concentration in acid-etched commercially pure titanium and titanium alloy implants: a comparative analysis of five implant systems.

OBJECTIVES: Acid etching is a popular method to texture the surface of dental implants. During etching, the titanium oxide protective layer is dissolved and small native hydrogen ions diffuse into the unprotected implant surface. They enrich the implant surface with hydrogen and precipitate into titanium hydride (TiH). The aim of this study was to measure the concentration of TiH at the implant surface and the total concentration of Hydrogen at five commercially available implant systems, made of either commercially pure (cp) titanium or titanium alloy. MATERIAL AND METHODS: X-Ray diffraction (XRD) was conducted on each implant system to determine the compounds present at the implant surface. Following a TiH(2)/Ti calibration curve, the concentration of TiH was determined. Concentration of hydrogen in the implants was measured by the inert gas fusion thermal conductivity/infrared detection method. RESULTS: XRD data showed that TiH was present on all cp titanium implants but not on the alloyed implants. TiH concentration varied between 5% and 37%. Hydrogen concentration varied between 43 and 108 ppm, no difference in uptake was found between the cp titanium and alloyed implants. Low solubility of hydrogen in alpha-titanium is responsible for precipitation into TiH. Stronger etching conditions led to higher concentration of TiH2-x. CONCLUSION: High solubility of hydrogen in the beta-phase of the alloy is preventing hydrogen from precipitating into TiH. All implants, even those lacking TiH at the surface, were enriched with hydrogen. In all implants, hydrogen concentration was within the normative limit of 130 ppm.

Periapical central giant cell granuloma misdiagnosed as odontogenic cyst.

AIM: To present the clinicopathological features of a series of four periapically located central giant cell granulomas (CGCGs) that were misdiagnosed and treated as being of endodontic origin. SUMMARY: Four cases of periapical CGCGs were submitted with a clinical diagnosis of either radicular or residual cyst. In two cases, root canal treatment had been performed previously. The patients were two women and two men whose age ranged from 31 to 85 years. Two cases were located in the mandibular premolar-molar region, and two in the anterolateral region of the maxilla. Two lesions were submitted for histological examination with a diagnosis of radicular cyst whereas the remaining two were submitted with a diagnosis of residual cyst. KEY LEARNING POINTS: Periapical giant cell lesions may be unilocular and therefore misdiagnosed as an endodontic lesion because of their radiographic similarity to an inflammatory periradicular lesion, especially if the teeth have been root filled or if the vitality is negative or doubtful. It is important to follow up the healing process of a periapical radiolucency related to a root filled tooth and, in case of persistence, to perform surgery and to submit the specimen for histological examination.

Recurrent peripheral giant cell granuloma associated with cervical resorption.

A case of recurrent peripheral giant cell granuloma in a 38-year-old man is reported. The lesion was localized on the attached gingiva of the lower left second premolar (tooth #35). The surgical excision of the lesion revealed a superficial resorption of the cervical region of the involved tooth. The resorption was smoothed out, and there was no sign of recurrence or further resorption after 14 months. Root resorption, although extremely rare, may be associated with peripheral giant cell granuloma.