Does a black light lens aid in composite removal?

OBJECTIVE

To evaluate the effectiveness of a black light lens as visual aid in composite restoration removal. Lost tooth structure, residual composite, and removal time were compared for operators with different levels of experience.

METHODS

Occlusal preparations in 24 matched-pair extracted molars were etched, bonded, restored with composite, and thermocycled. The restored teeth were radiographed and two faculty and two student doctors removed the restorations with or without a black light lens while time was recorded. Digital scans of the cavity before and after restoration removal were used to calculate lost tooth structure and residual composite.

RESULTS

Removal of restorations resulted in tooth structure loss and left residual composite. The use of the black light lens had no significant effect (two-way ANOVA; p value >0.05). However, operator experience significantly affected operating times and average depth of tooth structure loss (two-way ANOVA; p value <0.05). Student doctors assisted by the black light lost less tooth structure than experienced operators and improved their operating times (multiple comparisons; p value <0.05).

CONCLUSIONS

The black light lens did not conserve tooth structure or avoid composite remnants compared to routine operation, nor affected the operating time. However, less-experienced operators did benefit from the black light in conserving tooth structure and time.

CLINICAL SIGNIFICANCE

Replacement of defective composite restorations is a regular practice in restorative dentistry. When existing composite restorations are removed, loss of tooth structure is unavoidable. A black light lens might improve the ability of operators with less experience to conserve tooth structure even though it did not provide benefits for the experienced operators.

Prognostic Impact of Operator Experience and IVUS Guidance on Long-Term Clinical Outcomes After Complex PCI

BACKGROUND

Although consistent clinical data support intravascular ultrasound (IVUS) use during complex percutaneous coronary intervention (PCI), long-term follow-up outcomes on differential effects of IVUS according to operator experience are scarce.

OBJECTIVES

The current study aimed to evaluate the influence of operator experience on lesion complexity, long-term clinical outcomes, and the interactions of IVUS guidance in patients undergoing complex PCI.

METHODS

A total of 6,005 patients who underwent PCI with drug-eluting stents for complex lesions were recruited from the institutional registry of Samsung Medical Center. The study population was stratified by the use of IVUS and operator experience (less experienced operator [lifetime independent experience with PCI ≤5 years] vs experienced operator). The primary endpoint was a composite of cardiac death or target vessel myocardial infarction (TVMI) up to 10 years.

RESULTS

Compared with less experienced operators, experienced operators used IVUS more frequently (29.6% [1,128/3,805] vs 24.8% [546/2,200]; P < 0.001) and achieved a lower risk of cardiac death or TVMI (experienced vs less experienced, adjusted HR: 0.779; 95% CI: 0.663-0.915; P = 0.002). IVUS use was associated with a significantly lower risk of cardiac death or TVMI than angiography alone for less experienced operators (23.5% vs 11.4%; adjusted HR: 0.477; 95% CI: 0.337-0.673; P < 0.001) as well as experienced operators (18.0% vs 13.5%; adjusted HR: 0.747; 95% CI: 0.559-0.998; P = 0.048). There were significant interactions for the risk of cardiac death or TVMI between IVUS use and operator experience (P = 0.037).

CONCLUSIONS

PCI by experienced operators and the use of IVUS during complex PCI were independently associated with lower long-term risks of cardiac death or TVMI. The beneficial effects of IVUS were more prominent for less experienced operators. (Prospective Percutaneous Coronary Intervention Registry [SMC-PCI]; NCT05624905).

Influence of Operator Experience on Scanning Time and Accuracy with Two Different Intraoral Scanners - A Prospective Clinical Trial

Objective

Operator experience and scanner type may influence the time taken and obtained accuracy of intraoral scanning. This study aimed to evaluate the influence of operator experience on the scanning time and correlate the accuracy of the scans taken with two different intraoral scanners (TRIOS 3, 3Shape and i500, Medit).

Methods

In this trial, a total of 20 subjects who required intraoral scanning for orthodontic treatment were included. Intraoral scanning was done with two different scanners, TRIOS 3 and i500. One operator each with high (group 1), medium (group 2) and low (group 3) levels of experience performed intra-oral scanning with two different intraoral scanners. A One-Way ANOVA test was performed to assess the intergroup difference in scanning time and Kendall's tau's correlation test to determine the correlation between the experience of the operator and accuracy among the three groups using the two scanners. Also Independent samples t-test were performed to assess the intragroup differences in scanning time with two different scanners.

Results

The scanning time was influenced by the type of intraoral scanner and operator experience (p<0.05). No significant correlation between operator experience and scanning accuracy in the three groups was noted (p>0.05). Statistically significant intragroup differences in scanning time between the two scanners were noted (p<0.05).

Conclusion

Less experienced operators took more time to scan a subject. Accuracy of scanning among three groups using two scanners was not influenced by the experience of the operator. Scanning with i500 IOS took more time than TRIOS.

Investigation of Fluoroscopy Time and Radiation Dose by the Number of Cerebral Angiography Operator Experiences

Objective

We investigated the fluoroscopy time (FT) and radiation dose by the number of cerebral angiography (CA) operator experiences to clarify the learning curve of CA.

Methods

The subjects were cases for whom CA was performed at our hospital for 5 years between April 2015 and March 2020. Based on the number of CA operator experiences, they were classified into four groups: 1-50 cases (group A), 51-100 cases (group B), 101-200 cases (group C), and 201 cases and later (group D). The FT and radiation dose were retrospectively investigated.

Results

Of the 865 consecutive CA cases, 293 cases for follow-up, i.e. after treatment, 54 for arteriovenous shunt diseases, 21 lacking data, and 1 case requiring intervention for thrombosis during CA were excluded. In total, 496 CA cases were investigated. There were 61 cases in group A, 56 cases in group B, 44 cases in group C, and 335 cases in group D, and there was no significant difference in patient background factors among the groups. The median FT and radiation dose (interquartile range) in each group were 20.2 min (14.6) and 374 mGy (185.3) in group A, 14.8 min (12.1) and 366 mGy (167.9) in group B, 10.8 min (6) and 320 mGy (151.7) in group C, and 9.4 min (6.4) and 336 mGy (171) in group D. The FT was significantly shorter in group C than in group A, and significantly shorter in group D than in groups A, B, and C. The radiation dose was significantly lower in groups C and D than in groups A and B.

Conclusion

This study suggested that CA can be performed alone after experiencing approximately 100 cases as an operator.

Influence of operator experience on bond strength of different adhesives to dentin

Aim

Application of adhesive systems on dentin is a multistep, technique-sensitive procedure. Thus, the aim was to assess the effect of operator experience on the shear bond strength of an etch-and-rinse adhesive system and a self-etch adhesive system on dentin.

Materials and Methods

Forty-eight extracted human molar teeth were used in the study. They were embedded in an acrylic resin after cutting off the roots. The mesial and distal enamels of the teeth were removed to expose dentin surfaces. The samples were allocated to four groups (n = 12): Group 1: restorative dentistry specialist with 13 years of experience, Group 2: with 6 years of experience, Group 3: postgraduate operator with 2 years of experience, and Group 4: undergraduate student with 1 year of experience and familiar with adhesive with systems. Each operator applied an etch-and-rinse adhesive system (Adper Single Bond 2) to mesial surface and a self-etch adhesive system (Clearfil SE Bond) to distal surface (n = 12). Then, a composite resin (Filtek Z250) was inserted with the aid of a plastic ring (2 mm × 2 mm) and light polymerized. The specimens were stored in distilled water before shear bond strength test. A two-way ANOVA test was used for statistical analysis.

Results

No statistically significant difference was found between each operator type with respect to etch-and-rinse adhesive system (P > 0.05); however, the undergraduate student performed better than 2-year experienced operator with respect to self-etch system application (P < 0.05).

Conclusion

The shear bond strength of a self-etch system might vary according to the operator's experience.

Effect of operator skill on the dentin bonding ability of a self-adhesive resin cement after different adhesive treatments

This study evaluated the influence of operator skill on the shear bond strength of a self-adhesive resin cement to dentin after different adhesive treatments. Flat dentin surfaces were prepared on 160 extracted molars. The teeth were distributed evenly (n = 80) to 2 groups based on the operator's skill (undergraduate dental student vs operative dentistry specialist). The teeth in each operator group were distributed into 5 groups based on pretreatments used before they were cemented to indirect composite resin cylinders with Panavia SA Luting Plus resin cement. The operators prepared the dentin surfaces for bonding according to the following pretreatment groups: 1, no treatment; 2, phosphoric acid etching; 3, Clearfil Universal Bond in etch-and-rinse mode; 4, Clearfil Universal Bond in self-etching mode; and 5, Clearfil SE Bond 2-step adhesive. After cementation was performed by the 2 operator groups, shear bond strength testing was performed, and data were analyzed with 2-way analysis of variance. The effects of operator skill and surface pretreatment and their cumulative effect were statistically significant (P < 0.05). The shear bond strength of the control group in the student group was significantly greater than that of the specialist group (P = 0.02). In group 5 (2-step adhesive), the shear bond strength of the specialist group was significantly greater than that of the student group (P < 0.001). The use of acid etching and the 3 adhesive treatments improved the bonding ability of resin cement for the expert group. This positive effect was observed only in the etch-and-rinse and self-etching modes for the student group. Extensive clinical experience did not have a positive effect on the bonding effectiveness of resin cement with no pretreatment, while the expert group showed better results in applying this cement with a 2-step adhesive pretreatment.

Endovascular Treatment of Intracranial Atherosclerotic Stenosis: Current Debates and Future Prospects

Intracranial atherosclerotic stenosis (ICAS) is a common cause of transient ischemic attack (TIA) and ischemic stroke. Endovascular treatment, including balloon angioplasty alone, balloon-mounted stents, and self-expandable stent placement with or without prior angioplasty, is an alternative to medical treatment for the prevention of recurrent TIA or ischemic stroke in patients with ICAS. Although the SAMMPRIS and VISSIT trials supported medical management alone against endovascular treatments, both randomized controlled trials (RCT) were criticized due to flaws relating to patient-, intervention-, and operator-related factors. In this review, we discuss the current debate regarding these aspects and suggest approaches to solve current controversies in the future. In our opinion, endovascular treatment in carefully selected patients, individualized choice of endovascular treatment subtypes, and an experienced multidisciplinary team managing the patient in the pre-, peri- and post-procedural period have the potential to provide safe and efficious treatment of patients with symptomatic ICAS.

Evaluation of the Effect of Operator Experience on Outcome of Hepatic Artery Embolization of Hepatocellular Carcinoma in a Tertiary Cancer Center

RATIONALE AND OBJECTIVES

There is lack of information on the learning curve and the effect of operator's experience on the quality outcomes of transarterial hepatic embolization (TAE). The aim of this study was to evaluate the effect of operator experience on outcomes of TAE of hepatocellular carcinoma.

MATERIALS AND METHODS

Demographic characteristics and outcomes including overall survival (OS), time to local tumor progression (TLP), and post-procedure complications in patients with hepatocellular carcinoma treated with TAE were collected. Operators' experience was measured in years based on the years after completion of fellowship and the date of first embolization, and was divided into five groups: G1, less than 5 years of operator's experience (YOE) at the time of first embolization; G2, 5-10 YOE; G3, 10-15 YOE; G4, 15-20 YOE; and G5, more than 20 YOE. The effects of operator's experience and outcomes were assessed using linear regression.

RESULTS

From January 2012 to January 2015, 93 patients (age range = 30-86 years) were treated. The number of patients treated by each group was as follows: G1 = 12; G2 = 8; G3 = 23; G4 = 5; and G5 = 45. All groups were similar in regard to degree of cirrhosis, Barcelona Clinic Liver Cancer staging, and Child-Pugh score (P > .05). Median TLP was 8.8 months. TLP was 7.0, 6.8, 19.2, 7.9, and 8.2 months in G1, G2, G3, G4, and G5, respectively (P = .56). OS for 1, 2, and 3 years was 75%, 56%, and 42% for G1; 87%, 54%, and 54% for G2; 91%, 71%, and 45% for G3, 100%, 50%, and 0 for G4; and 84%, 65%, and 40% for G5.

CONCLUSION

Among interventional radiology fellowship-trained operators in a tertiary cancer center, OS, TLP, and post-procedure complications of TAE were not affected by the years of post-fellowship experience.

A prospective cohort study of the morbidity associated with operative vaginal deliveries performed by day and at night

OBJECTIVE

To evaluate maternal and neonatal outcomes associated with operative vaginal deliveries (OVDs) performed by day and at night.

DESIGN

Prospective cohort study.

SETTING

Urban maternity unit in Ireland with off-site consultant staff at night.

POPULATION

All nulliparous women requiring an OVD with a term singleton fetus in a cephalic presentation from February to November 2013.

METHODS

Delivery outcomes were compared for women who delivered by day (08:00-19:59) or at night (20:00-07:59).

MAIN OUTCOME MEASURES

The main outcomes included postpartum haemorrhage (PPH), anal sphincter tear and neonatal unit admission. Procedural factors included operator grade, sequential use of instruments and caesarean section.

RESULTS

Of the 597 women who required an OVD, 296 (50%) delivered at night. Choice of instrument, place of delivery, sequential use of instruments and caesarean section did not differ significantly in relation to time of birth. Mid-grade operators performed less OVDs by day than at night, OR 0.60 (95% CI 0.43 to 0.83), and a consultant supervisor was more frequently present by day, OR 2.26 (95% CI 1.05 to 4.83). Shoulder dystocia occurred more commonly by day, OR 2.57 (95% CI 1.05 to 6.28). The incidence of PPH, anal sphincter tears, neonatal unit admission, fetal acidosis and neonatal trauma was similar by day and at night. The mean decision to delivery intervals were 12.0 and 12.6 min, respectively.

CONCLUSIONS

There was no evidence of an association between time of OVD and adverse perinatal outcomes despite off-site consultant obstetric support at night.

Learning curve for fetoscopic laser surgery using cumulative sum analysis

OBJECTIVE

To identify a learning curve and monitor operator performance for fetoscopic laser surgery for twin-to-twin transfusion syndrome using cumulative sum analysis.

DESIGN

Retrospective cohort study.

SETTING

National tertiary referral center for invasive fetal therapy.

POPULATION

A total of 340 consecutive monochorionic pregnancies with twin-to-twin transfusion syndrome treated with fetoscopic laser coagulation between August 2000 and December 2010.

METHODS

A learning curve was generated using learning curve cumulative sum analysis and cumulative sum methodology to assess changes in double survival across the case sequence. Laser surgery was initially performed by two operators, joined by a third and fourth operator after 1 and 2 years, respectively.

MAIN OUTCOME MEASURES

Individual operator performance, double perinatal survival at 4 weeks.

RESULTS

Overall survival of both twins occurred in 59% (201/340), median gestational age at birth was 32.0 weeks. Cumulative sum graphs showed that level of competence for double survival for the operators was reached after 26, 25, 26, and 35 procedures, respectively. Two operators kept their competence level and continued to improve after completing the initial learning process; two others went out of control at one point in time, according to the cumulative sum boundaries. A difference in learning effect was associated with number of procedures performed annually and previous experience with other ultrasound-guided invasive procedures.

CONCLUSIONS

This study shows that all operators reached a level of competence after at least 25 fetoscopic laser procedures and confirms the value of using the cumulative sum method both for learning curve assessment and for ongoing quality control.