Mahatma Gandhi Institute of Medical Sciences

This study investigates the influence of different irrigation systems on thermal management during implant osteotomy, along with their effects on implant stability and peri-implant tissue health.

The study comprised an initial in vitro phase using freshly sacrificed goat mandibles to compare internal and external irrigation systems versus external irrigation alone. Temperature variations were measured at multiple distances from the osteotomy site. Subsequently, a clinical trial included 26 patients receiving 30 implants, where periodontal pocket depth, crestal bone loss, and implant stability were assessed over a one-year follow-up period.

In the in vitro phase, both irrigation methods showed comparable thermal management, with no significant temperature differences observed between groups. Clinical outcomes from the trial demonstrated stable implant integration and negligible peri-implant tissue complications across both irrigation approaches. Periodontal pocket depths and crestal bone loss were similar between groups, indicating no significant difference in long-term outcomes.

The findings highlight the effectiveness of both internal and external irrigation systems, as well as external irrigation alone, in minimizing thermal damage during implant osteotomy. These irrigation methods support stable implant integration and preserve peri-implant tissue health over a one-year period. Optimized irrigation techniques are crucial for enhancing implant dentistry practices and ensuring favorable patient outcomes.

Radiotherapy treatment planning for head and neck cancers (HNCs) is usually based on contrast-enhanced computed tomography (CECT). However, soft-tissue contrast is better evident in magnetic resonance imaging (MRI). The study evaluates the gross tumour volumes (GTVs) delineated on CECT vs MRI along with their Dice similarity coefficients (DSCs) and resultant impact on the dose-volume histogram (DVH) parameters, conformity index (CI), and homogeneity index (HI) during intensity-modulated radiotherapy (IMRT) planning in HNCs.

This prospective study enrolled 50 consecutive HNC patients. Following CECT and MRI simulations, GTV_p (primary) and GTV_n (node) were delineated independently on these co-registered images. Corresponding MRI volumes were then copied onto co-registered CECT images and IMRT plans were generated on the CECT-defined planning target volume (PTV) of primary and nodes (PTV_p+n).

The GTV_p, GTV_n, and GTV_p+n observed on MRI were significantly larger than the corresponding GTVs defined on CECT (all P < .001). The DSC of GTV_p, GTV_n, and GTV_p+n was inversely correlated with the corresponding % differences of GTV_p (r = -0.49, P < .001), GTV_n (r = -0.41, P = .021), and GTV_p+n (r = -0.73, P < .001) between CECT and MRI. The mean DSCs of GTV_p, GTV_n, GTV_p+n, and PTV_p+n were 0.78, 0.32, 0.67, and 0.78, respectively. This led to significant differences in CI and HI (both P < .001), as well as other DVH parameters (D₂, D₅₀, D₉₅, D₉₈, V₉₅, and V₁₀₀, all P < .001) between CECT- and MRI-defined PTV_p+n.

The GTVs and PTV_p+n defined on MRI were significantly greater than those depicted on CECT, resulting in significant differences in DSC, DVH parameters, CI, and HI. Thus, IMRT planning for HNCs based on CECT-defined PTV appears inappropriate. The study emphasises the importance of accurate delineation to ensure adequate coverage of the target volume and the potential benefit of MRI in this regard.