Teledentistry adoption and applications: An American Dental Association Clinical Evaluators Panel survey.

BACKGROUND: The rise of teleworking technologies has affected various industries, including dentistry. Although some dentists have used it for some time, many are discovering the benefits of incorporating this technology to complement their existing patient care capabilities. METHODS: To assess how clinicians are using teledentistry in their practices, an electronic survey was developed and deployed to the American Dental Association Clinical Evaluators (ACE) Panel on February 27, 2023. The survey link remained open for 2 weeks. Nonrespondents received reminders after 1 week. RESULTS: Of the 244 respondents (24% response rate), 30% use teledentistry in their practices, with more than one-half of those using synchronous (53%) or asynchronous teledentistry (63%). The most common reasons for incorporating teledentistry were increased convenience for patients (53%), COVID-19 (50%), and increased accessibility to providers (39%). Teledentistry can help serve patients of all ages (the lowest represented age group [0-5 years] had 42% of dentists treating them) and distances, with 63% of teledentistry patients fewer than 20 miles away. Most users adopted teledentistry within the past 3 years and use it fewer than 5 hours per month. Benefits cited include a reduced number of in-person patient visits (63%) and increased access and quality of care (57%). Among nonusers, 60% felt there was no need, and 39% had concerns with reimbursement. CONCLUSIONS: Teledentistry has gained popularity in since the onset of the COVID-19 pandemic but may be underused, despite its potential to benefit a wider range of patients and applications than many believe. PRACTICAL IMPLICATIONS: Education on the capabilities and benefits of teledentistry may help increase adoption and improve patient care.

Intraoral appliance use in dental practice: An American Dental Association Clinical Evaluators Panel survey.

BACKGROUND: A growing variety of intraoral appliances are being used in dental practice. Insight about the range of applications and practice workflow as well as factors effecting change in practice trends was sought. METHODS: A survey was developed to ascertain intraoral appliance use, fabrication methods, staff involvement, and patient experiences in dental practice. The survey was sent to ADA Clinical Evaluators Panel members on July 25, 2022, in Qualtrics and remained open for 2 weeks. After 1 week, those who had not responded yet were sent reminders. Data were analyzed descriptively in SAS Version 9.4. RESULTS: Of the 286 respondents (a 28% response rate), 88% reported providing patients with intraoral appliances apart from providing patients with removable partial dentures. More than one-half of the respondents reported offering bleaching trays (88%), flippers or Essix retainers (83%), splints (81%), athletic mouthguards (72%), orthodontic retainers (60%), fluoride trays (56%), and clear aligners (55%). The biggest changes to practice in the past 5 years with respect to intraoral appliances have been intraoral scanning (56%) and the increase in the variety of intraoral appliances in use. Although 72% reported dental assistants were involved in obtaining impressions and fabricating models for intraoral appliances and 76% reported that laboratory technicians were involved in fabricating intraoral appliances, nearly all (97%) respondents indicated that the dentist was involved in the delivery of appliances to patients. Patient education about the use of their appliances appeared to be delivered using multiple approaches, given that it was reported to occur orally (95%), in print (61%), and visually (42%). That 90% of respondents reported having engaged in continuing education courses about intraoral appliances aligns with these appliances becoming a routine part of dental practice, with both increasing applications and improvements in the relevant technology. CONCLUSIONS: Intraoral appliances were found to be used commonly in dental practice, and often multiple members of the dental care team were engaged in the fabrication processes. PRACTICAL IMPLICATIONS: There likely will be ongoing interest in relevant learning opportunities about technologic advances as well as the increasingly diverse list of applications for intraoral appliances.

Oral health care practice patterns for geriatric patients: An American Dental Association Clinical Evaluators Panel Survey.

BACKGROUND: The geriatric adult population is expanding rapidly in the United States, with more of these patients expected to visit the dentist in the coming years. Understanding the dental community's preparedness and comfort treating this demographic is timely. METHODS: Survey questions were developed to assess how dentists treat geriatric patients, what challenges they face, and what tools they need to provide the best care. This set of questions was administered electronically and emailed to the American Dental Association Clinical Evaluators (ACE) Panel on March 29, 2022. After 2 weeks, the survey closed, and data were summarized descriptively. RESULTS: Of the 269 respondents, 59% indicated that treating geriatric patients is more challenging than treating nongeriatric patients. The most frequently cited challenges include comorbidities and their management (86%), cognitive impairment (68%), and home care needs for some of these patients (69%). The top 3 symptoms seen in these patients are dry mouth (89%), carious lesions (86%), and tooth wear (75%). Seventy-six percent of respondents reported being comfortable treating this demographic, and most (58%) indicated that training as a student contributed to this competency. CONCLUSIONS: Most respondents are comfortable treating geriatric patients, but they still face many challenges, with managing comorbidities with dental treatment a top concern. PRACTICAL IMPLICATIONS: A sound understanding of the impact of aging and associated medical treatments on oral tissues and patient management is essential. Equally important is finding innovative ways to improve access to care for this vulnerable population.

Oral-systemic health considerations in dental settings: An American Dental Association Clinical Evaluators Panel survey.

BACKGROUND: With an increased emphasis on considering optimal oral health in the context of overall health and well-being, there is interest in understanding how practicing dentists are using information about their patients' overall health status. METHODS: A survey tool was developed to understand how dentists assess the health status of their patients, the frequency at which they are gathering this information, and how they work with their medical colleagues. Emails with an electronic survey link were sent to 997 American Dental Association Clinical Evaluators (ACE) panel members on November 23, 2021. The survey closed after 2 weeks, and data were analyzed descriptively. RESULTS: A total of 258 (26%) ACE panel members responded to the survey. At initial visits, the dentist (60%) often discusses and reviews the patient's medical history, but in subsequent appointments, this task is often completed by the dental assistant (34%) or dental hygienist (32%). At every dental visit, 75%, 66%, and 33% of the respondents ask about and record changes to medical history, medication list, and visits with other health care professionals, respectively. Of the respondents, 85% collect at least 1 vital sign, and more than 90% use the medical history, medication list, and patient interview. A total of 32% of respondents reported disease monitoring is in their scope of practice, and, among them, cardiovascular conditions are the most frequent health condition seen. On average, 12% of patients are referred to another health care provider weekly. CONCLUSIONS: Most dentists use the patient's medical history and medication list and collect vital signs, but the frequency and application of these assessments vary. PRACTICAL IMPLICATIONS: Optimal oral health is integral to overall health, and identifying opportunities to improve communication and data sharing among all health care professionals can affect the patient's health positively.

Dentist-administered vaccines: An American Dental Association Clinical Evaluators Panel survey.

BACKGROUND: With many states in the United States permitting dentists to administer the COVID-19 vaccine, there is much discussion about their scope of practice in relation to delivering other vaccines. METHODS: Survey questions were developed to assess dentists' awareness about their vaccine administration scope of practice and attitudes and barriers if choosing to incorporate vaccine delivery into their practice scope. The survey was deployed electronically to members of the American Dental Association Clinical Evaluators (ACE) Panel (N = 989) on September 2, 2021, and remained open for 2 weeks. Data were summarized descriptively in Qualtrics and SAS Version 9.4. RESULTS: Of the 330 ACE Panel members who responded to the survey, 42% were not aware of which vaccines their state permits them to deliver. More than one-half (55%) would be willing to administer influenza or COVID-19 vaccines in their practice setting, but at present only 2% of respondents administer vaccines. To overcome vaccine administration barriers, the top 3 resources respondents want access to are the following: training or education, financial support, and access to protocols. Of all the respondents, 91% indicated the dental hygienist should be involved in certain capacities. CONCLUSIONS: Few dentists are administering vaccines, possibly owing to a number of challenges. Dental hygienists may play an integral role in the administration of vaccines in the dental clinic, but few dentists are educating their patients about vaccines. PRACTICAL IMPLICATIONS: Although dentists wishing to administer vaccines in their practice may encounter barriers, support at the state, federal, and organizational levels could help them overcome these challenges.

Smoking cessation counseling and treatment: An American Dental Association Clinical Evaluators Panel survey.

BACKGROUND: Given the oral health implications of smoking, vaping, and using smokeless tobacco products (STPs), the dental office can be an effective setting for clinicians to offer smoking cessation counseling and treatment (SCCT). METHODS: A survey tool was developed to assess dentists' approach and experience with SCCT. This survey was deployed electronically on May 21, 2021, to the American Dental Association Clinical Evaluators (ACE) Panel (N = 982), and 1 week later, nonresponders were sent reminders. Results were summarized in SAS Version 9.4. RESULTS: Of the 283 survey responders, one-half offered SCCT to their patients. Of those who offered SCCT, 69% would be willing to prescribe pharmacologic agents to help with cessation. Nine of 10 times, SCCT conversations included the dentist. Of the 49% of respondents who did not offer SCCT, one-quarter were current or past smokers, vapers, or STP users. Out of all of the survey respondents, 40% were aware that SCCT is part of most medical benefits. Most respondents (82%) perform surgeries on patients who smoke, vape, or use STPs. CONCLUSIONS: Implementation of SCCT in the dental office was split among ACE panelists, but when it was offered, the dentist was almost always involved. Awareness about SCCT medical benefits and surgical protocols for current smokers, vapers, and STP users differed among this sample. PRACTICAL IMPLICATIONS: Dentists can benefit from more formal training and resources around SCCT and access to reimbursement for having these crucial conversations with their patients.

Intraoral scanners: An American Dental Association Clinical Evaluators Panel survey.

BACKGROUND: Dentists may choose to integrate intraoral scanners (IOSs) into their practices, but there are many different IOS technologies and system generations to choose from, posing a challenge for dentists who want to invest in them. METHODS: A survey of IOS use rates, advantages, satisfaction, and training was developed and deployed through Qualtrics to the 968 members of the American Dental Association Clinical Evaluators (ACE) Panel on February 19, 2021. Nonrespondents were sent reminders, and data were analyzed in SAS Version 9.4 (SAS). RESULTS: A total of 369 panelists responded to the survey. IOS use was split among the ACE Panel; 53% indicated they use one in their practice. The top reason respondents began using IOSs was to improve clinical efficiency (70%). Ninety percent of respondents use IOSs for single tooth-supported crowns, and 58% began using IOSs less than 4 years ago. Most users are at least mostly satisfied (91%) with the results. Among nonusers, the top reason for not using an IOS was the high level of financial investment (66%); 34% and 40% of nonusers are thinking of buying or training with IOSs in 2021, respectively. CONCLUSIONS: Uptake of IOSs is split; most users are satisfied with their results, and nonusers cited financial barriers as the most common reason for not investing in one. PRACTICAL IMPLICATIONS: As IOSs continue to penetrate the market and dentists are faced with a decision whether to invest in one, they will need guidance on how to choose the most appropriate device for their patients.

Defective restoration repair or replacement: An American Dental Association Clinical Evaluators Panel survey.

BACKGROUND: Clinicians often encounter defective restorations and are faced with the difficult decision of whether to repair the existing restoration or replace it. METHODS: An electronic survey on repairing or replacing defective restorations was developed to assess how clinicians are making these decisions and the technical aspects considered when making a repair. E-mails containing the survey link were sent to the American Dental Association Clinical Evaluators (ACE) Panel on August 14, 2019, and the survey remained open for 2 weeks. Nonrespondents were sent reminders 1 week after deployment. RESULTS: Approximately 4 of every 5 respondents repair defective restorations. The top 3 conditions for making these repairs were noncarious marginal defects (87%), partial loss or fracture of the restoration (79%), and crown margin repair due to carious lesions (73%). Among respondents who repair defective restorations, almost all repair direct resin composite (98%), whereas approximately one-third do not repair the other restorative materials (that is, amalgam, glass ionomer, and fractured indirect all-ceramic crowns). Resin composite is used most often to repair resin direct composite restorations, and likewise, glass ionomer is used most often to repair glass ionomer restorations. Only 54% of respondents use amalgam to repair amalgam restorations. Surface treatments varied among the 3 available restorations types. CONCLUSIONS: Many dentists are actively making restoration repairs, but choosing clinical scenarios to make these repairs is material dependent. PRACTICAL IMPLICATIONS: The repair of defective restorations is an acceptable and more conservative alternative than restoration replacement, and its success depends on proper case selection, material, and technique.

Zirconia restorations: An American Dental Association Clinical Evaluators Panel survey.

BACKGROUND: Zirconia is a relatively new dental material used for indirect dental restorations. Little is known about how dental practitioners are using this material in their practice. METHODS: A survey on zirconia restorations was developed and administered electronically through e-mail communications to the American Dental Association Clinical Evaluators (ACE) Panel on August 31, 2020. Reminders were sent to nonrespondents, and the survey closed 2 weeks after the launch date. RESULTS: When using zirconia for a restoration, respondents choose it to restore natural teeth (99%) more often than implants (76%). Almost all respondents (98%) use it for posterior crowns, whereas approximately two-thirds (61%) use it for anterior crowns. Restoration removal or replacement and shade matching and translucency were the top 2 cited disadvantages of zirconia, whereas most of the respondents (57%) cited flexural strength or fracture resistance as the biggest advantage. Fine diamonds and ceramic polishers are used most often to polish and adjust zirconia restorations, whereas coarse diamond rotary instruments and those made specifically for zirconia are most frequently used for removing these restorations. Compared with metal ceramic restorations, more than 50% of respondents experience debonding more often with zirconia restorations. CONCLUSIONS: Dentists recognize the favorable fracture resistance and flexural strength properties of zirconia, and most use similar techniques when adjusting and removing this material. Removing these restorations and shade matching are a struggle for many. PRACTICAL IMPLICATIONS: Dentists may benefit from tips on the best methods to remove, shade match, and adhesively bond zirconia restorations.

Bonding crowns and bridges with resin cement: An American Dental Association Clinical Evaluators Panel survey.

BACKGROUND: Bonding crowns and bridges with resin cement can improve retention and reinforcement of the restoration. However, there is variation in the steps taken by different practitioners to achieve this goal. METHODS: The authors developed a survey on bonding dental crowns and bridges with resin cement and distributed it electronically to the American Dental Association Clinical Evaluators (ACE) Panel on May 22, 2020. The survey remained open for 2 weeks. Descriptive data analysis was conducted using SAS Version 9.4. RESULTS: A total of 326 panelists responded to the survey, and 86% of respondents who place crowns or bridges use resin cements for bonding. When placing a lithium disilicate restoration, an almost equal proportion of respondents etch it with hydrofluoric acid in their office or asked the laboratory to do it for them, and more than two-thirds use a silane primer before bonding. For zirconia restorations, 70% reported their restorations are sandblasted in the laboratory, and 39% use a primer containing 10-methacryloyloxydecyl dihydrogen phosphate. One-half of respondents clean their lithium disilicate or zirconia restorations with a cleaning solution. Resin cements used with a primer in the etch-and-rinse mode are the most widely used. The technique used to cure and clean excess resin cement varies among respondents. CONCLUSIONS: The types of resin cements used, tooth preparation, crown or bridge preparation, and bonding technique vary among this sample. PRACTICAL IMPLICATIONS: Although many dentists bond crowns and bridges on the basis of best practices, improvement in the process may be achieved by dentists communicating with their laboratory to confirm the steps performed there, ensuring an effective cleaning technique is used after try-in and verifying that the correct primer is used with their chosen restorative material.

Dental light-curing units: An American Dental Association Clinical Evaluators Panel survey.

BACKGROUND: The ability to polymerize light-activated dental materials with dental light-curing units (DLCUs) has revolutionized dentistry. However, proper DLCU use is essential for ensuring the effectiveness and performance of these materials. METHODS: The authors developed an electronic cross-sectional survey in the American Dental Association Qualtrics Research Core platform. The survey included questions about DLCU use, unit type and selection, training, maintenance, technique, and safety measures. The authors deployed the survey to 809 American Dental Association Clinical Evaluators (ACE) panelists on October 9, 2019, and sent reminder links to nonrespondents 1 week later. They conducted exploratory and descriptive analyses using SAS software Version 9.4. RESULTS: Of the 353 ACE panelists who completed the survey, most used a DLCU in their practices (99%), and light-emitting diode multiwave units were the most common type of DLCU units (55%). Dentists use DLCUs for over one-half of their appointments each day (mean [standard deviation], 59% [22%]). Regarding technique, respondents reported that they modify their curing technique on the basis of material thickness (79%) and material type or light tip-to-target distances (59%). Maintenance practices varied, with two-thirds of respondents reporting that they periodically check their DLCUs' light output. CONCLUSIONS: DLCUs are an integral part of a general dentist's daily practice, but maintenance, ocular safety, and technique varied widely among this sample. PRACTICAL IMPLICATIONS: Because clinical effectiveness requires delivery of an adequate amount of light energy at the appropriate wavelength, variation in DLCU maintenance, safety, and techniques suggest that dentists could benefit from additional guidance and training on DLCU operation.

An American Dental Association Clinical Evaluators Panel survey.

BACKGROUND: Human papillomavirus (HPV) is a sexually transmitted oncovirus associated with several malignancies, including oropharyngeal squamous cell carcinoma. The 9-valent HPV vaccine can help protect against the high-risk HPV strains most commonly associated with HPV-related cancers. METHODS: The authors used an electronic survey to assess the roles of dentists and their team members in discussing the HPV vaccine, as well as administering the vaccine in a dental setting. On December 6, 2019, the authors e-mailed a survey link to the American Dental Association Clinical Evaluators (ACE) Panel (n = 813), a sample of American Dental Association member dentists. After 1 e-mail reminder, the survey closed on December 19, 2019, and the authors conducted exploratory and descriptive data analyses using SAS Version 9.4 (SAS). RESULTS: A total of 329 dentists responded to the survey, and 83 (25%) of them reported that they or their team members discuss the implications of the HPV vaccine with age-eligible patients or their parents or guardians. Dentists lead two-thirds (n = 218) of the discussions, and the clinical examination is the most frequent moment during the patient visit in which HPV-related topics are discussed. Some of the top reasons respondents mentioned for not discussing the vaccine in their practice were the perception that these discussions are best left to other health care professionals and not knowing how to address the topic with patients. If the scope of dental practice is expanded to include administering the vaccine, 125 (38%) of respondents would feel uncomfortable administering the vaccine. The most common potential barriers to administering the vaccine in a dental setting include obtaining reimbursement and vaccine management and preservation. CONCLUSIONS: The survey results suggest that dentists' comfort levels and perceived roles in discussing and administering the HPV vaccine vary. PRACTICAL IMPLICATIONS: There is a need to further define the role of dentists and their team members in the promotion and administration of the HPV vaccine. Resources for dentists and dental team members may be helpful to support professional education and communication about the HPV vaccine.

Repair or replacement of defective direct resin-based composite restorations: contemporary teaching in U.S. and Canadian dental schools.

BACKGROUND: Opportunities exist to promote minimally invasive dentistry by repairing rather than replacing defective and failing direct resin-based composite restorations. The authors conducted a study to investigate the current teaching of such techniques in U.S. and Canadian dental schools. METHODS: In late 2010, the authors, with the assistance of the Consortium of Operative Dentistry Educators, invited 67 U.S. and Canadian dental schools to participate in an Internet-based survey. RESULTS: The response rate was 72 percent. Eighty-eight percent of the dental schools taught repair of defective direct resin-based composite restorations. Of these schools, 79 percent reported providing both didactic and clinical teaching. CONCLUSIONS: Although teaching repair of defective resin-based composite restorations was included in the didactic curricula of most schools, students in some schools did not gain experience in minimally invasive management of defective resin-based composite restorations by means of performing repair procedures. The American Dental Association's Code on Dental Procedures and Nomenclature does not have a procedure code for resin-based composite restoration repairs, which may limit patients' access to this dental treatment. CLINICAL IMPLICATIONS: Teaching dental students minimally invasive dentistry procedures, including restoration repair, extends the longevity of dental restorations and reduces detrimental effects on teeth induced by invasive procedures, thereby serving the interests of patients.

Minimally invasive management of dental caries: contemporary teaching of posterior resin-based composite placement in U.S. and Canadian dental schools.

BACKGROUND: Resin-based composites are an increasingly popular material for restoring posterior teeth, permitting minimally invasive cavity preparations and esthetic restorations. The authors investigated current teaching of the placement of posterior resin-based composites in U.S. and Canadian dental schools. METHODS: In late 2009 and early 2010, the authors, with the assistance of the Consortium of Operative Dentistry Educators (CODE), invited 67 dental schools to participate in an Internet-based survey. RESULTS: The response rate was 73 percent. Although all schools taught the placement of resin-based composites in occlusal and most occlusoproximal cavities, eight schools (16 percent) did not teach placement of three-surface occlusoproximal resin-based composite restorations in permanent molars. Resin-based composites accounted for 49 percent of direct posterior restorations placed by dental students in 2009 and 2010, a 30 percent increase from 2005. CONCLUSIONS: Teaching placement of posterior resin-based composites continues to increase in dental schools in the United States and Canada, with predoctoral students gaining, on average, an equal amount of experience placing posterior resin-based composites and amalgams in terms of numbers of restorations. CLINICAL IMPLICATIONS: Evidence-based, up-to-date teaching programs, including those in operative dentistry, are needed to best prepare students for careers in dentistry.

Dental erosion and acid reflux disease: an overview.

Dental erosion can be difficult to detect, especially in the early stages when lesions are subtle and can be easily overlooked. Patients often are not aware of erosion until the dentition has sustained severe damage that requires extensive and expensive dental rehabilitation. The pH of stomach acid is much lower than the critical pH of enamel dissolution; therefore, reflux of stomach contents into the oral cavity over an extended period of time can cause severe loss of tooth structure. Dental treatment for reflux-induced erosion should focus not only on appropriate restoration but also on all available preventive measures, such as neutralization of acid and remineralization or strengthening of enamel against acid attack. Dentists must maintain a high degree of suspicion for reflux-induced erosion whenever a patient displays symptoms of acid reflux disease or a pattern of erosion that suggests an intrinsic source of acid exposure.

Intra- and intermolecular NMR studies on the activation of arylcyclometallated hafnium pyridyl-amido olefin polymerization precatalysts.

Pyridyl-amido catalysts have emerged recently with great promise for olefin polymerization. Insights into the activation chemistry are presented in an initial attempt to understand the polymerization mechanisms of these important catalysts. The activation of C1-symmetric arylcyclometallated hafnium pyridyl-amido precatalysts, denoted Me2Hf{N(-),N,C(-)} (1, aryl = naphthyl; 2, aryl = phenyl), with both Lewis (B(C6F5)3 and [CPh3][B(C6F5)4]) and Brønsted ([HNR3][B(C6F5)4]) acids is investigated. Reactions of 1 with B(C6F5)3 lead to abstraction of a methyl group and formation of a single inner-sphere diastereoisomeric ion pair [MeHf{N(-),N,C(-)}][MeB(C6F5)3] (3). A 1:1 mixture of the two possible outer-sphere diastereoisomeric ion pairs [MeHf{N(-),N,C(-)}][B(C6F5)4] (4) is obtained when [CPh3][B(C6F5)4] is used. [HNR3][B(C6F5)4] selectively protonates the aryl arm of the tridentate ligand in both precatalysts 1 and 2. A remarkably stable [Me2Hf{N(-),N,C2}][B(C6F5)4] (5) outer-sphere ion pair is formed when the naphthyl substituent is present. The stability is attributed to a hafnium/eta(2)-naphthyl interaction and the release of an eclipsing H-H interaction between naphthyl and pyridine moieties, as evidenced through extensive NMR studies, X-ray single crystal investigation and DFT calculations. When the aryl substituent is phenyl, [Me2Hf{N(-),N,C2}][B(C6F5)4] (10) is originally obtained from protonation of 2, but this species rapidly undergoes remetalation, methane evolution, and amine coordination, giving a diastereomeric mixture of [MeHf{N(-),N,C(-)}NR3][B(C6F5)4] (11). This species transforms over time into the trianionic-ligated [Hf{N(-),C(-),N,C(-)}NR3][B(C6F5)4] (12) through activation of a C-H bond of an amido-isopropyl group. In contrast, ion pair 5 does not spontaneously undergo remetalation of the naphthyl moiety; it reacts with NMe2Ph leading to [MeHf{N(-),N}NMe2C6H4][B(C6F5)4] (7) through ortho-metalation of the aniline. Ion pair 7 successively undergoes a complex transformation ultimately leading to [Hf{N(-),C(-),N,C(-)}NMe2Ph][B(C6F5)4] (8), strictly analogous to 12. The reaction of 5 with aliphatic amines leads to the formation of a single diastereomeric ion pair [MeHf{N(-),N,C(-)}NR3][B(C6F5)4] (9). These differences in activation chemistry are manifested in the polymerization characteristics of these different precatalyst/cocatalyst combinations. Relatively long induction times are observed for propene polymerizations with the naphthyl precatalyst 1 activated with [HNMe3Ph][B(C6F5)4]. However, no induction time is present when 1 is activated with Lewis acids. Similarly, precatalyst 2 shows no induction period with either Lewis or Brønsted acids. Correlation of the solution behavior of these ion pairs and the polymerization characteristics of these various species provides a basis for an initial picture of the polymerization mechanism of these important catalyst systems.

Duration and timing of sensitivity related to bleaching.

PROBLEM: Reports of sensitivity vary greatly from one study to another, probably because studies are small. Generally, only the percentage of subjects is reported. PURPOSE: This study reports sensitivity using a large database. We investigated the source, duration, and timing of sensitivity during 14 days of active bleaching. MATERIALS AND METHODS: One hundred and seventy-two people recorded sensitivity from any of the five sources on a daily basis. RESULTS: No one withdrew from the study because of sensitivity. Forty-seven percent of participants experienced sensitivity. Seventy-seven percent had sensitivity of 3 or fewer days. Temperature sensitivity tended to occur later in the 14-day bleaching cycle, and hot and cold sensitivity tended to occur together. CONCLUSIONS: There was great variability in sensitivity levels from person to person. Temperature sensitivity tended to occur later in the active phase of bleaching, whereas irritation of the tongue tended to occur earlier. CLINICAL SIGNIFICANCE: The results from a large group of people are more likely to include a wide cross-section of the population sampled. This data provides practitioners with a better estimate of what their patients are likely to experience. It is estimated that, during 2 weeks of active bleaching, 77% of people will experience 3 or fewer days of sensitivity. On average, sensitivity is short-lived, thus making it is easy to underestimate the importance of discussing sensitivity with patients considering bleaching. However, for some, the duration of sensitivity is much greater and has a very negative impact on satisfaction.

Performance of 2 packable composites at 12 months.

OBJECTIVE: The purpose of this randomized, double-blind, clinical trial was to compare the marginal seal of 2 packable resin composite materials in moderate to large lesions on molars. METHOD AND MATERIALS: Fifty participants in need of a moderate to large Class 2 or complex Class 1 molar restoration were randomly distributed into 4 groups, to receive either Alert (Jeneric/Pentron) or SureFil (Dentsply/Caulk) resin composite with or without a surface sealer. Each participant received one restoration. With the exception that study protocol limited increments to no more than 4 mm, teeth were restored according to the manufacturers' instructions, and surface sealer was applied after finishing in the designated groups. Use of Alert includes routine placement of a flowable composite liner. Clinical performance of the restorations was evaluated in 8 categories at baseline, 6 months, and 12 months. The 2 materials were compared to determine if a difference in marginal seal existed between groups. The number of restorations exhibiting marginal staining was compared using Fischer's exact test at a significance level of 5%. RESULTS: Six participants did not present for the 12-month recall. At 12 months, 19 (90.5%) Alert restorations and 15 (68.2%) SureFil restorations did not exhibit marginal staining. There was no statistically significant difference between the 2 restorative materials for marginal staining. Overall, 3 restorations were rated as failures. CONCLUSION: At 12 months, materials placed with a flowable liner were not associated with a significant reduction in marginal staining.

Safety and efficacy of a nightguard bleaching agent containing sodium fluoride and potassium nitrate.

OBJECTIVES: Transient sensitivity during bleaching is generally reported to affect 67% of patients. While most people tolerate this sensitivity, some find it impossible to continue treatment. The purpose of this study was to determine the safety and efficacy of an experimental, low-sensitivity bleaching agent. METHOD AND MATERIALS: Twenty-two participants bleached for a minimum of 6 hours per night over a 2-week period. The bleaching agent used, Experimental Product E, is a 10% carbamide peroxide gel containing potassium nitrate and sodium fluoride. Evaluations were performed at baseline and 1,2,13, and 26 weeks. Color change was measured using a value-ordered Vita classic shade guide and a colorimeter. Sensitivity of the teeth, gingiva, tongue, and/or throat was measured daily using a patient log. RESULTS: The median color change after 2 weeks was eight tabs. Approximately 36% reported sensitivity during the active whitening phase of the study. As a group, participants reported sensitivity during 13.7% of the total days spent whitening. CONCLUSION: Experimental Product E was shown to be safe. Participants experienced minor sensitivity during the active bleaching phase only. Experimental Product E was shown to be an effective bleaching agent for the subjects tested in this study.

Application of rapid prototyping to operative dentistry curriculum.

Computers are becoming an integral part of dental education and dental practice. Rapid prototyping is a technique for the production of solid objects from computer models. The variety of rapid prototyping devices and materials that can be processed is increasing all the time. In this article, the authors present a discriminative learning device and associated exercises for developing visual recognition skills and examine the potential for the application of rapid prototyping to the operative dentistry curriculum. Other rapid prototyping technologies as applied in dentistry are also discussed.