Accuracy and Self-Confidence Level of Freehand Drilling and Dynamic Navigation System of Dental Implants: An In Vitro Study

BACKGROUND AND OBJECTIVE

The impact of the experience of the clinician on learning a new skill or equipment was still an intriguing subject. The goal of this research is to determine the accuracy level of a dynamic navigation system to that of freehand drilling by expert and novice practitioners with varied levels of experience. Additionally, the duration of the surgical procedure and the self-confidence level of the surgeons were also evaluated.

MATERIALS AND METHODS

An analog impression of the patient was used to make 20 polyurethane simulation models of the maxilla. Five expert and five inexperienced surgeons prepared the site and placed the implants at random on ten models each. Two different techniques were used to insert dental implants: freehand and dynamic navigation systems. Dental implants were placed in Group 1 utilizing a computer-assisted dynamic navigation device. The implants in Group 2 were secured using free-hand drilling. The dental implants were inserted first in the maxillary right first molar, then in the maxillary right lateral incisor, and the maxillary left second premolar. Preoperative and postoperative CBCT scans were superimposed by employing the Evalunav software and contrasted. The coronal 3-D, apex 3-D, apex vertical depth, and angular deviations for both procedures were evaluated. A pre-tested self-confidence questionnaire was also administered to assess the self-confidence of the practitioners. The duration of the surgical time was also documented for each strategy. The t-test was used to measure the difference in accuracy and confidence levels between freehand and dynamic navigation systems among expert and novice surgeons using SPSS software (IBM Corp., Armonk, NY, USA).

RESULTS

A total of 60 implants were used (three insertion sites, two methods, and 10 practitioners). Each of the five expert and novice clinicians implanted 15 implants (five models each). Except for entry 3-D, there was a statistically significant difference between the two approaches in all of the primary outcome variables. The apex 3-D (5.89±1.08 mm) and apex vertical (2.08±1.27 mm) dimensions of the dynamic navigation system were significantly smaller than those of the freehand drilling approach (p<005). Dynamic navigation and freehand drilling had angular deviations of 7.16±1.76ᵒ and 9.06±2.18ᵒ, respectively (p=0.0004). The apex vertical deviation was reduced in the navigation technique (2.07±1.5 mm) than in the freehand drilling (2.86±1.4 mm) by experienced practitioners (p=0.04). The difference in time between the two procedures was determined to be statistically highly significant (p<0.001) by both expert and novice surgeons. Furthermore, when contrasting with experienced practitioners, novice practitioners had an overall increase in surgery time (p<0.001) for both approaches.

CONCLUSION

The current in vitro study found that the dynamic navigation system enables more accurate implant placement than the freehand drilling technique, irrespective of the experience of the surgeons. However, this technique appears to benefit novice practitioners more, as they can profoundly minimize their deviations while accomplishing results comparable to those of expert surgeons.

3D-Printed Implant Sliding Guide: A New Dental Implant Surgical Guide

PURPOSE

To compare the linear and angular deviations of sites prepared for implants with the proposed 3D-printed sliding guide vs a 3D-printed conventional sleeveless static guide.

MATERIALS AND METHODS

This study consisted of two groups: a control group of 14 3D-printed conventional sleeveless static guides, and a test group of 37 3D-printed sliding guides. The guides were designed to drill 37 implant sites in each group. Linear and angular deviations were determined after scanning the drilled casts. Linear deviations were measured at the coronal and apical aspects of the drilled implant sites at 5-, 10-, 15-, and 20-mm distances.

RESULTS

There were no significant differences between the control and study groups regarding the coronal and 5-mm apical linear deviations. The angular and 10-, 15-, and 20-mm linear deviations of the 3D-printed sliding guide were significantly smaller than the control group.

CONCLUSIONS

The proposed 3D-printed sliding guide could reduce the angular deviation of drilled implant sites from the planned positions, which is reflected in reducing the linear apical deviation of prepared implant sites longer than 5 mm.

Exploring the Relationship Between Clinical Presentation in Hallux Valgus and Response to AbobotulinumtoxinA Treatment

The relationship between pain/disability and angular deviation of the hallux valgus (HV), and the impact of orthotic use, laterality, and pain variability on treatment outcomes remain unclear. This was explored in post hoc analyses of a placebo-controlled trial of abobotulinumtoxinA (aboBoNT-A; Dysport®) for HV-associated pain (NCT03569098). The primary endpoint was not met in this study (change from baseline Numeric Pain Rating Scale [NPRS] score vs placebo at week 8); however, there was a greater reduction from baseline in mean NPRS score at week 12 with aboBoNT-A 500U versus placebo (p = .06). Adults with painful HV without surgery were randomized (1:1:1) to aboBoNT-A 300U, aboBoNT-A 500U, or placebo. NPRS was completed for 7 days before baseline and weeks 4, 8, and 12. Over-the-counter orthoses were permitted. Participants (N = 186) had a mean [standard deviation, SD] age of 48.2 [13.1] years, 18% (33/186) used orthotics, and 67% (124/186) had bilateral HV. No associations between baseline pain severity and angular deviation were identified. Participants with high pain variability at baseline (SD > 2) had a poorer response to aboBoNT-A treatment than those with less variability. In conclusion, no relationship between HV-related pain/disability and angular deviation was observed. PLAIN LANGUAGE SUMMARY: A bunion (medical term: hallux valgus) is a common adult foot problem in which the big toe points inward toward the other toes, and this can be painful. How much the big toe points inward (how deformed the foot is) has been linked to the amount of pain the patient experiences. A better understanding of this foot deformity and bunion pain will help doctors and patients to make the right treatment decisions. A study was completed looking at how injections of a type of botulinum toxin (abobotulinumtoxinA) into specific muscles in the foot may help to reduce bunion pain in patients without surgery. This subsequent analysis of the study data looked at the amount of foot deformity in patients, the bunion pain they experienced, and which factors affected how well abobotulinumtoxinA worked to reduce bunion pain. The results of this study showed that the amount of foot deformity was not linked to the level of bunion pain. When deciding the best treatment option to relieve bunion pain, it is important that doctors not only consider how deformed the foot is, but also other important factors such as foot pain levels.

In Vitro Comparison between Metal Sleeve-Free and Metal Sleeve-Incorporated 3D-Printed Computer-Assisted Implant Surgical Guides

The present study aims to compare the accuracy of metal sleeve-free 3D-printed computer-assisted implant surgical guides (MSF group) (n = 10) with metal sleeve-incorporated 3D-printed computer-assisted implant surgical guides (MSI group) (n = 10). Implants of diameter 4.0 mm and 5.0 mm were placed in the left second premolars and bilateral first molars, respectively, using a fully guided system. Closed-form sleeves were used in teeth on the left and open-form sleeves on the right. The weight differences of the surgical guides before and after implant placement, and angular deviations before and after implant placement were measured. Weight differences were compared with Student's t-tests and angular deviations with Mann-Whitney tests. Cross-sectional views of the insert parts were observed with a scanning electron microscope. Preoperative and postoperative weight differences between the two groups were not statistically significant (p = 0.821). In terms of angular deviations, those along the mesiodistal direction for the left second premolars were significantly lower in the MSF group (p = 0.006). However, those along the mesiodistal direction for the bilateral molars and those along the buccolingual direction for all teeth were not significantly different (p > 0.05). 3D-printed implant surgical guides without metal sleeve inserts enable accurate implant placement without exhausting the guide holes, rendering them feasible for fully guided implant placement.

Enhanced Coalescence-Induced Droplet-Jumping on Nanostructured Superhydrophobic Surfaces in the Absence of Microstructures

Superhydrophobic surfaces are receiving increasing attention due to the enhanced condensation heat transfer, self-cleaning, and anti-icing properties by easing droplet self-removal. Despite the extensive research carried out on this topic, the presence or absence of microstructures on droplet adhesion during condensation has not been fully addressed yet. In this work we, therefore, study the condensation behavior on engineered superhydrophobic copper oxide surfaces with different structural finishes. More specifically, we investigate the coalescence-induced droplet-jumping performance on superhydrophobic surfaces with structures varying from the micro- to the nanoscale. The different structural roughness is possible due to the specific etching parameters adopted during the facile low-cost dual-scale fabrication process. A custom-built optical microscopy setup inside a temperature and relative humidity controlled environmental chamber was used for the experimental observations. By varying the structural roughness, from the micro- to the nanoscale, important differences on the number of droplets involved in the jumps, on the frequency of the jumps, and on the size distribution of the jumping droplets were found. In the absence of microstructures, we report an enhancement of the droplet-jumping performance of small droplets with sizes in the same order of magnitude as the microstructures. Microstructures induce further droplet adhesion, act as a structural barrier for the coalescence between droplets growing on the same microstructure, and cause the droplet angular deviation from the main surface normal. As a consequence, upon coalescence, there is a decrease in the net momentum in the out-of-plane direction, and the jump does not ensue. We demonstrate that the absence of microstructures has therefore a positive impact on the coalescence-induced droplet-jumping of micrometer droplets for antifogging, anti-icing, and condensation heat transfer applications.

Dosimetric impact of angular deviations in positioning for spinal radiosurgery

PURPOSE

During image-guided radiosurgery, it is common to account only for translational shifts while leaving rotational deviations uncorrected. The aim of this study is to investigate the rotational setup deviations and estimate the dosimetric impact in spinal radiosurgery.

MATERIALS AND METHODS

Stereoscopic image registrations of 711 spine radiosurgery procedures (546 patients) were retrospectively reviewed and classified to cervical (C), thoracic (T), and lumbar (L) spines. The probability of rotational deviations were estimated in three orthogonal axis. In order to investigate the dosimetric impact, the original simulation CT images were rotated in the range of ±5 deg in each axis. Then, the dosimetric changes were recorded; including the coverage (V90) and minimum dose (Dmin) to the target, and the dose of 10% volume (D10) and maximum dose (Dmax) to the spinal cord.

RESULTS

Target rotations of >5 deg and >3 deg occurred respectively in 1% and 8% of cases. The mean rotations were small (|μ|<0.6 deg) with no axis and site dependent trends. The standard deviations (σ) of different sites and axes ranged from 1.4 to 2.0 deg (mean σ=1.7 deg). The overall dosimetric changes of the target coverage(V90) and cord D10 were small. Five degree rotation resulted in a target V90 decrease of 1±1%, 2±2% and 3±1%, respectively in the lateral, vertical, and longitudinal axes. The corresponding cord D10 increased by 3±6%, 2±2%, and 6±5%. The changes in cord Dmax ranged from 92% to 138% of the original reference spinal cord. Corresponding changes in target Dmin were 59~106%.

CONCLUSION

Large target rotations occurred in a small percentage of patients. The overall dosimetric impact on target coverage and cord D10 was small. However larger effects were observed on the target Dmin and cord Dmax. Special care must be taken for targets of elongated shapes involving multiple vertebrae.