1.
Laser all-ceramic crown removal-a laboratory proof-of-principle study-Phase 2 crown debonding time
Rechmann, Peter; Buu, Natalie C.H.; Rechmann, Beate M.T. ...
Lasers in surgery and medicine,
October 2014, Letnik:
46, Številka:
8
Journal Article
Background and Objectives
The removal of all‐ceramic crowns is a time consuming procedure in the dental office. Little research has been done in alternative removal techniques for all‐ceramic crowns. ...
The objective of the second phase of this proof‐of‐principle laboratory pilot study was to evaluate whether Ivoclar Vivadent all‐ceramic crowns can be efficiently removed from natural teeth without damage to the underlying tooth structure using an Erbium laser.
Study Design/Materials and Methods
The ceramic materials used were IPS E.max CAD Lithium‐disilicate (LS2) (E.max CAD) and IPS E.max ZirCAD Zirconium‐oxide (ZrO2) (ZirCAD) (Ivoclar, Vivadent, Liechtenstein).
Molars, either as stand‐alone teeth or placed in an artificial row of teeth, were prepared to receive all‐ceramic crowns. Copings and full contour crowns with either featheredge or regular margins were produced. The all‐ceramic crowns were bonded to the teeth with Ivoclar Multilink Automix. The time for Er:YAG laser debonding of each crown was then measured. The Er:YAG (LiteTouch, Syneron, Yokneam, Israel) was used with an 1,100 µm diameter fiber tip with energies up to 600 mJ per pulse (wavelength 2,940 nm, 10 Hz repetition rate, pulse duration 100 µs at 126 mJ/pulse, and 400 µs at 590 mJ/pulse). The irradiation was applied at a distance of 10 mm from the crown surface following a defined pattern. Air‐water spray was applied to the crowns at a rate of 67 ml/minute.
Results
All of the all‐ceramic crowns were successfully debonded with the laser. On average, an all‐ceramic E.max CAD crown was debonded in 190 ± 92 seconds (average ± SD). The debonding time for ZirCAD featheredge crowns was 226 ± 105 seconds and for ZirCAD crowns with regular margins it was 312 ± 102 seconds. No crowns fractured and no damage to the underlying dentin was detected. The bonding cement deteriorated due to the Er:YAG irradiation. Additionally, no carbonization at the dentin/cement interface was observed.
Conclusion
Er:YAG laser energy can successfully be used to efficiently debond all‐ceramic full contour crowns from natural teeth without damage to the underlying tooth structure. Lasers Surg. Med. 46:636–643, 2014. © 2014 Wiley Periodicals, Inc.
več
Dostopno za:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
2.
Laser all-ceramic crown removal-A laboratory proof-of-principle study-Phase 1 material characteristics
Rechmann, Peter; Buu, Natalie C.H.; Rechmann, Beate M.T. ...
Lasers in surgery and medicine,
October 2014, Letnik:
46, Številka:
8
Journal Article
Background and Objectives
The removal of all‐ceramic crowns is a time consuming and destructive procedure in the dental office. The removal of all‐ceramic crowns using Er:YAG lasers has not been ...
previously described in the scientific literature. The objective of this laboratory proof‐of‐principle study was to evaluate whether with regards to absorption and transmission characteristics of bonding cements and ceramics all‐ceramic crowns can be removed from natural teeth using an Erbium laser.
Study Design/Materials and Methods
The Fourier Transform Infrared Spectroscopy (FTIR) was used on flat ceramic samples (IPS Empress Esthetic (EE), E.max CAD, and E.max ZirCAD) to assess which infrared laser wavelengths transmit through the ceramics. Additionally, FTIR spectra for four bonding cements (Variolink Veneer, Variolink II, Multilink Automix, and SpeedCEM) were obtained. The Er:YAG laser energy transmission (wavelength 2,940 nm, 10 Hz repetition rate, pulse duration 100 µs at 126 mJ/pulse to 300 µs at 508 mJ/pulse) through different ceramic thicknesses was measured. Ablation thresholds for bonding cements were determined. Cement samples were directly irradiated or laser light was transmitted through ceramic samples.
Results
While the ceramics did not show any characteristic water absorption bands in the FTIR, all bonding cements showed a broad H2O/OH absorption band. Some cements exhibited a distinct absorption peak at the Er:YAG laser emission wavelength. Depending on the ceramic thickness, EE and E.max CAD ceramics transmitted between 21 and 60% of the incident Er:YAG energy, with E.max CAD transmitting more energy than EE at comparable thicknesses. In contrast, E.max ZirCAD transmitted only 5–10% of the incident energy. Initial signs of cement deterioration occurred at 1.3–2.6 J/cm2. Multilink Automix, SpeedCEM, and Variolink II started ablation at 4.4–4.7 J/cm2. Variolink Veneer needed 44% less energy for ablation.
Conclusion
Er:YAG laser energy can be transmitted through all‐ceramic materials and those transmitted energies are sufficient for ablation of bonding cements. Lasers Surg. Med. 46:628–635, 2014. © 2014 Wiley Periodicals, Inc.
več
Dostopno za:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
3.
Dostopno za:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
4.
Er:YAG laser debonding of porcelain veneers
Morford, Cynthia K.; Buu, Natalie C.H.; Rechmann, Beate M.T. ...
Lasers in surgery and medicine,
December 2011, Letnik:
43, Številka:
10
Journal Article
Background and Objectives
The removal of porcelain veneers using Er:YAG lasers has not been previously described in the scientific literature. This study was designed to systematically investigate ...
the efficacy of an Er:YAG laser on veneer debonding, possibly without damage to the underlying tooth, and preservation of the veneer integrity.
Study Design/Materials and Methods
The Fourier Transform Infrared Spectroscopy was used on 10 flat veneer samples (IPS Empress Esthetic, e.max Press HT) to assess which infrared laser wavelengths transmits through a veneer. Additionally, Fourier Transform Infrared (FTIR) spectra for a bonding cement (RelyX) were obtained. Consequently, Er:YAG laser energy transmission (wavelength 2,940 nm, 10 Hz repetition rate, pulse duration 100 µseconds at 133 mJ/pulse) through different veneer thicknesses was measured. Twenty‐four veneers were bonded to freshly extracted and prepared incisors. The energy necessary for debonding was determined and then the veneers were debonded with the laser. Time needed for total debonding was measured and possible damage to the underlying tooth structure was assessed by light microscopy.
Results
While the veneer materials did not show any characteristic water absorption bands in the FTIR, the bonding cement showed a broad H2O/OH absorption band. The veneers transmitted between 11.5% and 43.7% of the incident Er:YAG energy with Emax transmitting twice the energy as EE at comparable thicknesses. Initial signs of cement ablation occurred at 1.8–4.0 J/cm2 with the fiber tip positioned at a distance of 3–6 mm from the veneer surface and 133 mJ output energy. All 24 bonded veneers were completely removed with an average removal time of 113 ± 76 seconds. Underlying tooth structure was not damaged. The debonding mainly occurred at the cement/veneer interface. None of the Emax veneers fractured during debonding, while 36% of the EE did.
Conclusion
Er:YAG laser irradiation effectively debonds porcelain veneers while preserving tooth structure. Maintaining veneer integrity possibly depends on the flexure strength of the veneer porcelain. Lasers Surg. Med. 43:965–974, 2011. © 2011 Wiley Periodicals, Inc.
več
Dostopno za:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
5.
Criteria for selection to anesthesia residency programs: a survey of Canadian anesthesia program directors
Niburski, Kacper; Buu, Natalie
Canadian medical education journal
12, Številka:
4
Journal Article
Introduction: Applicants to specialty programs lack guidance on knowing what exactly is desired by selection committees and program directors. Anesthesia is especially opaque, given its failure to ...
provide transparency reports nationally. This study was developed to survey Canadian anesthesia program directors about the aspects of the application package desired in an anesthesia applicant. The primary objective is to identify the preferred attributes of anesthesia applications by those mandating the selection committees.
Methods: Survey was developed via Google Surveys, and sent online over a period of two months in June and July 2020. All program directors were sent requests for filling in the survey. STATA was used for all statistical analyses. Two analyses, Mann-Whitney and ANOVA tests, were performed for comparison groups. A p < 0.05 was considered significant.
Results: Fourteen of seventeen (83%) Canadian anesthesia program directors completed the survey. Having done an anesthesia elective, good performance in it, and excellence of preclinical academic performance were considered among the most important aspects of the application package with the highest ranking important and smallest standard deviation. Any form of red flag was also considered an important criterion, again with little variation among program directors. The reference letters selected by the applicants were also important, with a personal relationship and well written reference being identified as most important (p < 0.05).
Conclusions: An applicant who has good academic performance, having anesthesia elective experience, personal, well-written reference letters, and general activity and interests that are not necessarily anesthesia-focused would be favoured by Canadian anesthesia programs.
več
Dostopno za:
NUK, UL, UM, UPUK
6.
Dostopno za:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
7.
The emergence of patterned movement during late embryogenesis of Drosophila
Pereanu, Wayne; Spindler, Shana; Im, Elisabeth ...
Developmental neurobiology (Hoboken, N.J.),
October 2007, Letnik:
67, Številka:
12
Journal Article
Larval behavioral patterns arise in a gradual fashion during late embryogenesis as the innervation of the somatic musculature and connectivity within the central nervous system develops. In this ...
paper, we describe in a quantitative manner the maturation of behavioral patterns. Early movements are locally restricted “twitches” of the body wall, involving single segments or parts of segments. These twitches occur at a low frequency and have low amplitude, reflecting weak muscle contractions. Towards later stages twitches increase in frequency and amplitude and become integrated into coordinated movements of multiple segments. Most noticeable among these is the peristaltic wave of longitudinal segmental contractions by which the larva moves forward or backward. Besides becoming more complex as development proceeds, embryonic movements also acquire a pronounced rhythm. Thus, late embryonic movements occur in bursts, with phases of frequent movement separated by phases of no movement at all; early movements show no such periodicity. These data will serve as a baseline for future studies that address the function of embryonic lethal genes controlling neuronal connectivity and larval behavior. We have analyzed behavioral abnormalities in two embryonic lethal mutations with severe neural defects, tailless (tll), which lacks the protocerebrum, and glial cells missing (gcm), in which glial cells are absent. Our results reveal prominent alterations in embryonic motility for both of these mutations, indicating that the protocerebrum and glial cells play a crucial role in the neural mechanism controlling larval movement in Drosophila. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007
več
Dostopno za:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
8.
Report of two cases of endobronchial tumour mass resection in children
Johansen, Mathias; Lakheeram, Indrani; Buu, Natalie
Canadian journal of anesthesia,
09/2021, Letnik:
68, Številka:
9
Journal Article
Purpose
Anesthesia for endotracheal tumour mass resection in pediatric patients is a rare, complex, and high-risk procedure. The purpose of this case report is to emphasize the importance of ...
multidisciplinary team collaboration and close communication during the perioperative management of shared airway surgery.
Clinical features
A six-year-old boy with no previous history of comorbidity and a 13-yr-old boy with a six-month history of upper respiratory tract infection, refractory asthma, chronic wheeze, and exercise-related dyspnea presented for acute endobronchial tumour mass resection. Decreased pulmonary function, religious beliefs (Jehovah’s Witness), risk of intraluminal bleeding, and imminent complete airway collapse constitute areas of specific interest.
Conclusion
Anesthesia for endotracheal tumour mass resection in pediatric patients is a rare, complex, and high-risk procedure. Decreased pulmonary function and low respiratory reserves combined with the need for extensive surgical airway access warrants multidisciplinary team collaboration and close communication. Maintaining spontaneous respiration is paramount to reduce the risk of hypoxemia-induced adverse events and preoperative considerations should include the possible need for extracorporeal membrane oxygenation. Finally, the use of nasal high flow for shared airway surgery shows promising prospects warranting further investigation.
več
Dostopno za:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
9.
Dostopno za:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
10.
Dostopno za:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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