Why Guided When Freehand Is Easier, Quicker, and Less Costly?

Dental implants are subject to masticatory loads of varying magnitude. Implant performance is closely related to load transmission at the bone-to-implant interface where bone quality will be highly variable. The type and architecture of bone is known to influence its load bearing capacity and it has been demonstrated that poorer quality bone is associated with higher failure rates. To date, bone classifications have only provided rough subjective methods for pre-operative assessment, which can prove unreliable. The results of an extensive analysis of computerized tomography scans using Simplant software (Columbia Scientific Inc., Columbia, MD, USA) demonstrate that an objective scale of bone density based on the Houndsfield scale, can be established and that there is a strong correlation between bone density value and subjective quality score (P = 0.002) as well as between the bone density score and the region of the mouth (P < 0.001).

The purpose of the present clinical study was (1) to evaluate the Osstell as a diagnostic tool capable of differentiating between stable and mobile ITI implants, (2) to evaluate a cut-off threshold implant stability quotient (ISQ) value obtained at implant placement (ISQitv) that might be predictive of osseointegration, (3) to compare the predictive ISQitv of immediately loaded (IL) implants and implants loaded after 3 months (DL). Two patient groups were enrolled, 18 patients received 63 IL implants and 18 patients were treated with 43 DL implants. The ISQ was recorded at implant placement, after 1, 2, 4, 6, 8, 10 and 12 weeks. All implants passed the 1-year loading control. Two implants failed, one DL implant with ISQ at placement (ISQi) of 48 and one IL implant with ISQi of 53. The resonance-frequency analysis (RFA) method was not a reliable diagnostic tool to identify mobile implants. However, implant stability could be reliably determined for implants displaying an ISQ> or =47. After 1 year of loading, all DL implants with an ISQi> or =49 and all IL implants with an ISQi> or =54 achieved and maintained osseointegration. By the end of 3 months, implants with ISQi 69 had their stability decrease during the first 4 weeks before remaining stable. Although preliminary, these data might orient the practitioner to choose among various loading protocols and to selectively monitor implants during the healing phase.

To evaluate the association between trabecular bone density measurements of potential implant sites made on axial DICOM images (DentaCT software) and on the same images with eFilm workstation, to correlate bone densities in Hounsfield units (HU) with subjective classification, and to establish a quantitative scale for each bone quality class. Twenty-seven maxillary and 27 mandibular computed tomographic (CT) examinations of 75 potential implant sites were selected. Trabecular bone density was evaluated with DentaCT and eFilm. Bone quality was subjectively evaluated by 2 examiners. Descriptive statistics, between- and within-group comparison, correlation analysis, and Bland-Altman plot were used for data analysis. DentaCT measurements were higher than eFilm (P 200 to 400 HU. Different qualities of bone can be found in any of the anatomical regions studied (anterior and posterior sites of maxilla and mandible), which confirms the importance of a site-specific bone tissue evaluation prior to implant installation.