{"id":{"repo_id":"iupui","oai_identifier":"oai:scholarworks.indianapolis.iu.edu:1805/12841"},"canonical_url":"https://search.dev.ndltd.org/etd/iupui/oai:scholarworks.indianapolis.iu.edu:1805/12841","repository":{"repo_id":"iupui","name":"IUPUI","base_url":"https://scholarworks.indianapolis.iu.edu/server/oai/request"},"display":{"title":"Beam profile characterization of light-emitting-diode curing units and its effect on polymerization of a resin-matrix composite","abstract":"The general aim of this study was to investigate the influence of the localized irradiance beam profiles from multiple light-emitting-diode (LED) light-curing units (LCUs) on the polymerization pattern within a resin-matrix composite (RMC). Irradiance beam profiles were generated from one quartz-tungsten-halogen and various single and multiple emission peak LED LCUs using a camera-based beam profiler system combined with LCU power measurements obtained using an integrating sphere/spectrometer assembly. The influence of distance on irradiance, radiant exposure (RE) and degree of conversion (DC) on the top and bottom surfaces of a RMC increment, using various LCUs, at two clinically relevant distances was investigated. Molar absorptivity of the photoinitiators present in the nano-hybrid RMC (Tetric EvoCeram bleaching shade-XL) assessed was using UV-spectrophotometry. The correlation among irradiance, RE and DC was explored. A mapping approach was used to investigate DC, microhardness and cross-link density (CLD) within 5×5×2 mm specimens at various depths; top, 0.5, 0.7, 0.9, 1.1, 1.3,1.5 mm and bottom. The localized irradiance correlation with its corresponding DC, microhardness and CLD was explored, and localized DC correlation with microhardness was assessed. The DC was measured using micro-Raman spectroscopy, and CLD was assessed by an ethanol-softening method (%KHN reduction) using an automated microhardness tester. Molar absorptivity of diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide was 20-fold higher than camphorquinone. Non-uniform LCU beam profiles caused localized polymerization discrepancies that were significant at specific depths and points within the specimens with respect to DC, microhardness and CLD, which did not follow a specific pattern regardless of the LCU or curing distance assessed. A moderate correlation was displayed among irradiance, RE and DC. The localized irradiance from the LCUs was weakly correlated with the corresponding DC, microhardness and CLD on the top surface of a RMC at both curing distances. The localized microhardness was moderately correlated with DC. In conclusion, polymerization within the RMC investigated was non-uniform and did not reflect the LCU irradiance pattern at the area assessed. Also, a mapping approach within the specimens provided a detailed polymerization pattern assessment occurring within a RMC increment. Therefore, the LCUs explored may potentially increase the risk of RMC fracture.","abstract_html":"The general aim of this study was to investigate the influence of the localized irradiance beam profiles from multiple light-emitting-diode (LED) light-curing units (LCUs) on the polymerization pattern within a resin-matrix composite (RMC). Irradiance beam profiles were generated from one quartz-tungsten-halogen and various single and multiple emission peak LED LCUs using a camera-based beam profiler system combined with LCU power measurements obtained using an integrating sphere/spectrometer assembly. The influence of distance on irradiance, radiant exposure (RE) and degree of conversion (DC) on the top and bottom surfaces of a RMC increment, using various LCUs, at two clinically relevant distances was investigated. Molar absorptivity of the photoinitiators present in the nano-hybrid RMC (Tetric EvoCeram bleaching shade-XL) assessed was using UV-spectrophotometry. The correlation among irradiance, RE and DC was explored. A mapping approach was used to investigate DC, microhardness and cross-link density (CLD) within 5×5×2 mm specimens at various depths; top, 0.5, 0.7, 0.9, 1.1, 1.3,1.5 mm and bottom. The localized irradiance correlation with its corresponding DC, microhardness and CLD was explored, and localized DC correlation with microhardness was assessed. The DC was measured using micro-Raman spectroscopy, and CLD was assessed by an ethanol-softening method (%KHN reduction) using an automated microhardness tester. Molar absorptivity of diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide was 20-fold higher than camphorquinone. Non-uniform LCU beam profiles caused localized polymerization discrepancies that were significant at specific depths and points within the specimens with respect to DC, microhardness and CLD, which did not follow a specific pattern regardless of the LCU or curing distance assessed. A moderate correlation was displayed among irradiance, RE and DC. The localized irradiance from the LCUs was weakly correlated with the corresponding DC, microhardness and CLD on the top surface of a RMC at both curing distances. The localized microhardness was moderately correlated with DC. In conclusion, polymerization within the RMC investigated was non-uniform and did not reflect the LCU irradiance pattern at the area assessed. Also, a mapping approach within the specimens provided a detailed polymerization pattern assessment occurring within a RMC increment. Therefore, the LCUs explored may potentially increase the risk of RMC fracture.","abstract_has_math":false,"creators":["AlZain, Afnan Omar"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Platt, Jeffrey A."],"committee_chairs":[],"committee_members":[],"year":2017,"date_issued":"2017","date_published":"2017","updated_at":"2026-07-24T02:40:24Z","subjects":["Cross-link density","Degree of conversion","Light-curing unit","Light-emitting-diode","Resin composite","Beam profile"],"languages":["en_US"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier.doi","label":"DOI","values":["10.7912/C2GC8M"],"render_values":[{"text":"10.7912/C2GC8M","href":"https://doi.org/10.7912/C2GC8M","code":true}]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://dx.doi.org/10.7912/C2/1532"],"render_values":[{"text":"http://dx.doi.org/10.7912/C2/1532","href":"http://dx.doi.org/10.7912/C2/1532","code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/1805/12841","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Platt, Jeffrey A."]},{"key":"dc:contributor.other","label":"Dc Contributor Other","values":["Chu, Tien-Min G.","Bottino, Marco C.","Hara, Anderson T.","Goodpaster, John V.","Roulet, Jean-Francois"]},{"key":"dc:creator","label":"Author","values":["AlZain, Afnan Omar"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2017-06-05T17:49:52Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2019-05-25T09:30:13Z"]},{"key":"dc:date.issued","label":"Date","values":["2017"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Cross-link density","Degree of conversion","Light-curing unit","Light-emitting-diode","Resin composite","Beam profile"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en_US"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.doi","label":"DOI","values":["10.7912/C2GC8M"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/1805/12841","http://dx.doi.org/10.7912/C2/1532"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Indiana University-Purdue University Indianapolis (IUPUI)"]},{"key":"dc:description.abstract","label":"Abstract","values":["The general aim of this study was to investigate the influence of the localized irradiance beam profiles from multiple light-emitting-diode (LED) light-curing units (LCUs) on the polymerization pattern within a resin-matrix composite (RMC). Irradiance beam profiles were generated from one quartz-tungsten-halogen and various single and multiple emission peak LED LCUs using a camera-based beam profiler system combined with LCU power measurements obtained using an integrating sphere/spectrometer assembly. The influence of distance on irradiance, radiant exposure (RE) and degree of conversion (DC) on the top and bottom surfaces of a RMC increment, using various LCUs, at two clinically relevant distances was investigated. Molar absorptivity of the photoinitiators present in the nano-hybrid RMC (Tetric EvoCeram bleaching shade-XL) assessed was using UV-spectrophotometry. The correlation among irradiance, RE and DC was explored. A mapping approach was used to investigate DC, microhardness and cross-link density (CLD) within 5×5×2 mm specimens at various depths; top, 0.5, 0.7, 0.9, 1.1, 1.3,1.5 mm and bottom. The localized irradiance correlation with its corresponding DC, microhardness and CLD was explored, and localized DC correlation with microhardness was assessed. The DC was measured using micro-Raman spectroscopy, and CLD was assessed by an ethanol-softening method (%KHN reduction) using an automated microhardness tester. Molar absorptivity of diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide was 20-fold higher than camphorquinone. Non-uniform LCU beam profiles caused localized polymerization discrepancies that were significant at specific depths and points within the specimens with respect to DC, microhardness and CLD, which did not follow a specific pattern regardless of the LCU or curing distance assessed. A moderate correlation was displayed among irradiance, RE and DC. The localized irradiance from the LCUs was weakly correlated with the corresponding DC, microhardness and CLD on the top surface of a RMC at both curing distances. The localized microhardness was moderately correlated with DC. In conclusion, polymerization within the RMC investigated was non-uniform and did not reflect the LCU irradiance pattern at the area assessed. Also, a mapping approach within the specimens provided a detailed polymerization pattern assessment occurring within a RMC increment. Therefore, the LCUs explored may potentially increase the risk of RMC fracture."]},{"key":"dc:title","label":"Title","values":["Beam profile characterization of light-emitting-diode curing units and its effect on polymerization of a resin-matrix composite"]}]}],"canonical_facts":{"dc:contributor.advisor":["Platt, Jeffrey A."],"dc:contributor.other":["Chu, Tien-Min G.","Bottino, Marco C.","Hara, Anderson T.","Goodpaster, John V.","Roulet, Jean-Francois"],"dc:creator":["AlZain, Afnan Omar"],"dc:date.accessioned":["2017-06-05T17:49:52Z"],"dc:date.available":["2019-05-25T09:30:13Z"],"dc:date.issued":["2017"],"dc:description":["Indiana University-Purdue University Indianapolis (IUPUI)"],"dc:description.abstract":["The general aim of this study was to investigate the influence of the localized irradiance beam profiles from multiple light-emitting-diode (LED) light-curing units (LCUs) on the polymerization pattern within a resin-matrix composite (RMC). Irradiance beam profiles were generated from one quartz-tungsten-halogen and various single and multiple emission peak LED LCUs using a camera-based beam profiler system combined with LCU power measurements obtained using an integrating sphere/spectrometer assembly. The influence of distance on irradiance, radiant exposure (RE) and degree of conversion (DC) on the top and bottom surfaces of a RMC increment, using various LCUs, at two clinically relevant distances was investigated. Molar absorptivity of the photoinitiators present in the nano-hybrid RMC (Tetric EvoCeram bleaching shade-XL) assessed was using UV-spectrophotometry. The correlation among irradiance, RE and DC was explored. A mapping approach was used to investigate DC, microhardness and cross-link density (CLD) within 5×5×2 mm specimens at various depths; top, 0.5, 0.7, 0.9, 1.1, 1.3,1.5 mm and bottom. The localized irradiance correlation with its corresponding DC, microhardness and CLD was explored, and localized DC correlation with microhardness was assessed. The DC was measured using micro-Raman spectroscopy, and CLD was assessed by an ethanol-softening method (%KHN reduction) using an automated microhardness tester. Molar absorptivity of diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide was 20-fold higher than camphorquinone. Non-uniform LCU beam profiles caused localized polymerization discrepancies that were significant at specific depths and points within the specimens with respect to DC, microhardness and CLD, which did not follow a specific pattern regardless of the LCU or curing distance assessed. A moderate correlation was displayed among irradiance, RE and DC. The localized irradiance from the LCUs was weakly correlated with the corresponding DC, microhardness and CLD on the top surface of a RMC at both curing distances. The localized microhardness was moderately correlated with DC. In conclusion, polymerization within the RMC investigated was non-uniform and did not reflect the LCU irradiance pattern at the area assessed. Also, a mapping approach within the specimens provided a detailed polymerization pattern assessment occurring within a RMC increment. Therefore, the LCUs explored may potentially increase the risk of RMC fracture."],"dc:identifier.doi":["10.7912/C2GC8M"],"dc:identifier.uri":["https://hdl.handle.net/1805/12841","http://dx.doi.org/10.7912/C2/1532"],"dc:language.iso":["en_US"],"dc:subject":["Cross-link density","Degree of conversion","Light-curing unit","Light-emitting-diode","Resin composite","Beam profile"],"dc:title":["Beam profile characterization of light-emitting-diode curing units and its effect on polymerization of a resin-matrix composite"],"dc:type":["Dissertation"]},"updated_at":"2026-07-24T02:40:24Z"}