Evaluation of Primary Stability of Self‐Tapping and Non‐Self‐Tapping Dental Implants. A 12‐Week Clinical Study

Purpose: The aim of this study was to investigate the relationship between surgical techniques and implant macro‐design (self‐tapping/non‐self‐tapping) for the optimization of implant stability in the low‐density bone present in the posterior maxilla using resonance frequency analysis (RFA). Materials and Methods: A total of 102 implants were studied. Fifty‐six self‐tapping BlueSkyBredent® (Bredent GmbH&Co.Kg®, Senden, Germany) and 56 non‐self‐tapping Standard Plus Straumann® (Institut Straumann AG®, Waldenburg, Switzerland) were placed in the posterior segment of the maxilla. Implants of both types were placed in sites prepared with either lateral bone‐condensing or with bone‐drilling techniques. Implant stability measurements were performed using RFA immediately after implant placement and weekly during a 12‐week follow‐up period. Results: Both types of implants placed after bone condensing achieved significantly higher stability immediately after surgery, as well as during the entire 12‐week observation period compared with those placed following bone drilling. After bone condensation, there were no significant differences in primary stability or in implant stability after the first week between both implant types. From 2 to 12 postoperative weeks, significantly higher stability was shown by self‐tapping implants. After bone drilling, self‐tapping implants achieved significantly higher stability than non‐self‐tapping implants during the entire follow‐up period. Conclusions: The outcomes of the present study indicate that bone drilling is not an effective technique for improving implant stability and, following this technique, the use of self‐tapping implants is highly recommended. Implant stability optimization in the soft bone can be achieved by lateral bone‐condensing technique, regardless of implant macro‐design.     

Biomechanical and Bone Histomorphological Evaluation of Two Surfaces on Tapered and Cylindrical Root Form Implants: An Experimental Study in Dogs

Purpose: The aim of this study was to evaluate the early bone response of tapered and cylindrical root form implants with two different surface treatments in fresh extraction sockets after 4 and 8 weeks. Materials and Methods: Surface treatments and implant design comprised (n = 9 each): tapered with dual acid‐etched surface; tapered with dual acid‐etched and sandblasted surface (T DAE SB); cylindrical with dual acid‐etched surface (C DAE); and cylindrical with dual acid‐etched and sandblasted surface (C DAE SB). Implants were placed in the distal sockets of mandibular premolars (₂P_2,3P_3,4P₄) of six beagle dogs, remaining in vivo for 4 and 8 weeks. After sacrifice, the implants were subjected to torque to the point of interface fracture and subsequently nondecalcified for histomorphological study. Statistical analysis was performed by a General Linear Model (GLM) analysis of variance model with a significance level of 5%. Results: Torque to interface fracture was significantly greater for the C DAE SB group than for the other groups (p < .001). Histomorphological analysis showed woven bone formation around all implant surfaces at 4 weeks and its replacement by lamellar bone at 8 weeks. Study time (4 or 8 weeks) did not affect torque measures. Conclusions: The double acid‐etched and sandblasted sample surface increased early bone biomechanical fixation of both cylindrical and tapered root form implants. The cylindrical root form implants showed higher torque to interface fracture values when compared with the tapered root form implants. The C DAE SB surface group showed the highest biomechanical fixation values (p < .001).     

Intact parathyroid hormone measurement at 24 hours after thyroid surgery as predictor of parathyroid function at long term

Background

There is no consensus about the usefulness of postoperative intact parathyroid hormone (iPTH) determination to predict permanent hypoparathyroidism (pHPP). We evaluated the value of calcium (Ca²⁺) and iPTH concentration at 24 hours after total thyroidectomy (TT) for predicting pHPP.

Methods

Ca²⁺ and iPTH levels from 70 consecutive patients who underwent TT were measured at 24 hours and 6 months after TT.

Results

Five patients (7.1%) developed pHPP. An iPTH concentration ≤5.8 pg/mL at 24 hours after TT identified patients at risk for pHPP (sensitivity, 100%; specificity, 81.5%), but it was not accurate enough to predict its development (positive predictive value, 30%). Conversely, an iPTH level >5.8 pg/mL predicted normal parathyroid function at 6 months (negative predictive value, 100%). Compared with iPTH, a postoperative Ca²⁺ level ≤1.95 mmol/L was 60% sensitive and 78.5% specific to predict pHPP.

Conclusions

An iPTH concentration >5.8 pg/mL on the first postoperative day rules out pHPP with much better diagnostic accuracy than Ca²⁺. Postoperative iPTH could be helpful in identifying patients at risk for developing pHPP.     

Impact of preoperative radiation on survival of patients with T3N0 >7-cm non–small cell lung cancers treated with anatomic resection using the Surveillance,Epidemiology, and End Results database

Background

Very large non–small cell lung cancers (NSCLC) remain a therapeutic challenge. The objective of this study was to evaluate the effect of surgery in the presence and absence of neoadjuvant radiation (NRT) on survival of patients with T3N0 >7-cm NSCLCs.

Materials and methods

The Surveillance, Epidemiology, and End Results database was used to identify patients undergoing lobectomy or pneumonectomy for T3N0 NSCLC tumors >7 cm from 1999–2008. Patients were categorized into groups based on type of surgery performed and whether NRT was used. Five-year overall (OS) and lung cancer–specific survival (LCSS) were estimated by the Kaplan-Meier method and comparisons made using log-rank tests and Cox regression models.

Results

There were 1301 patients evaluated, including 1232 undergoing primary surgical therapy (PST) and 69 receiving NRT. NRT was not associated with improvements in 5-y OS (48% versus 41%, P = 0.062) or LCSS (59% versus 52%, P = 0.116) compared with PST. Lobectomies were associated with better 5-y OS (43% versus 33%; P = 0.006) and LCSS (54% versus 43%, P = 0.005) compared with pneumonectomies. On multivariate analysis, NRT did not produce any significant advantage in OS (P = 0.242) and LCSS (P = 0.208). Pneumonectomies were associated with significantly worse OS (hazard ratio, 1.32; P = 0.007) and LCSS (hazard ratio, 1.38; P = 0.005) when compared with lobectomies.

Conclusions

NRT, which most likely was a combination of chemotherapy and radiation, was not associated with improvements in OS or LCSS in patients with T3N0 >7-cm NSCLC compared with PST. When feasible, lobectomy appears more beneficial than pneumonectomy in terms of long-term survival for very large tumors.     

Dental injury after conventional direct laryngoscopy: a prospective observational study

This observational study assessed the frequency and risk factors of dental damage after classic direct laryngoscopy for tracheal intubation in 536 adult patients. The patients' sex, age, height, weight, dental condition, dental mobility, Mallampati class, interincisor gap, thyromental distance, neck circumference, and head and neck extension were recorded. From anaesthesia records, the difficulty of intubation, the number of attempts, type of neuromuscular blocking agent used and duration of anaesthesia were recorded. After anaesthesia, examination revealed that 134 patients (25.0%) had dental damage affecting 162 teeth (147 maxillary; 15 mandibular). Enamel fracture was the commonest injury. In tooth number 21, the interincisor gap (OR 2.5 (95% CI 1.0–5.9)) and in tooth number 22, the number of intubation attempts (OR 5.3 (95% CI 1.3–22.0)) were considered a risk factor for dental injury. Conventional direct laryngoscopy is associated with a strikingly high incidence of dental damage, although specific risk factors remain unclear.     

Magnetic resonance imaging of right ventricular papillary endothelial hyperplasia

Papillary endothelial hyperplasia (PEH) is a benign process characterized by endothelial cell proliferation in a papillary pattern, usually occurring in reaction to traumatic vascular stasis or a thrombus. Commonly found in the soft tissues of the neck and extremities, intracardiac lesions in the left atrium, left ventricle, and coronary atherotomy specimens associated with trauma or thrombus have rarely been reported. A single prior report of a pure, isolated form of intracardiac PEH in the literature is noted. To the best of our knowledge, the imaging characteristics have not been described. We describe the dynamic magnetic resonance characteristics of a pure, isolated PEH occurring in the right ventricle.