The inclusion of companion forages in the diet alongside perennial ryegrass increased dry matter intake and organic matter digestibility in sheep.

The inclusion of companion forages in the diet of ruminant animals is gaining popularity in temperate regions due to observed improvements in animal performance. The aim of this study was to assess the effect of diet type on DM intake (DMI) and organic matter digestibility (OMD) in sheep. Furthermore, the effect of sward type on diet nutritive quality was investigated. Five dietary treatments were investigated using a 5 × 5 Latin square design experiment: Perennial ryegrass (Lolium perenne L.; PRG) only or PRG plus white clover (Trifolium repens L.;PRG + WC), red clover (Trifolium pratense L.; PRG + RC), chicory (Chicorium intybus L.; PRG + Chic) or plantain (Plantago lanceolata L.; PRG + Plan) at a ratio of 75% PRG and 25% of the respective companion forage and 100% PRG for the grass only treatment on a DM basis. Twenty Belclare castrated male (wether) sheep were housed in metabolism crates across five feeding periods. Individual DMI and faecal output were recorded daily and digestibility parameters were subsequently calculated. Results show that the inclusion of any companion forage increased DMI (kg/day DM) which ranged from 1.55 ± 0.038 (PRG) to 1.76 ± 0.038 (PRG + Chic) (P < 0.001). The PRG + WC (825 ± 1.1), PRG + RC (823 ± 1.1) and PRG + Chic (826 ± 1.1) diets had a greater in vitro OMD (g/kg DM) when compared to PRG (819 ± 1.1) or PRG + Plan (816 ± 1.1) (P < 0.001). Furthermore, the PRG + Chic (830 ± 2.9) diet had a greater in vivo OMD (g/kg DM) (P < 0.01) when compared to the PRG, PRG + RC, and PRG + Plan diets. Regression analysis showed that in vitro estimates moderately reflected in vivo measurements (r2 = 0.61). The inclusion of any companion forage increased dietary CP content and reduced the proportion of NDF in the diet. Crude protein concentration increased by an average of 16.5 g/kg DM and NDF content was reduced by 25.3 g/kg DM, on average, with companion forage inclusion (P < 0.001). Results suggest that binary sward mixtures benefit pasture-based sheep production systems, boosting sward quality, aiding increased DM intakes of a more digestible diet in the summer period.

Periodontal education and assessment in the undergraduate dental curriculum-A questionnaire-based survey in European countries.

OBJECTIVES: This survey aimed to evaluate whether periodontal education and assessment in undergraduate dental curricula amongst the member countries of the European Federation of Periodontology (EFP) follow the competency-based curricular guidelines and recommendations developed by the Association for Dental Education in Europe. MATERIALS AND METHODS: A multiple-choice questionnaire was emailed to 244 dental institutes amongst the 24 EFP member countries between November 2014 and July 2015. RESULTS: Data were received from 16 (66.7%) EFP member countries. Out of 117 responding dental institutes, 76 (64.95%) were included as valid responders. In most of the institutes (86.3%), a minimum set of competencies in periodontology was taken into account when constructing their dental education programmes. Out of 76 responders, 98.1% included lecture-based, 74.1% case-based and 57.1% problem-based teaching in their periodontal curricula, whilst a minority (15.9%) also used other methods. A similar pattern was also seen in the time allocation for these four educational methods, that is, the highest proportion (51.8%) was dedicated to lecture-based teaching and only a small proportion (5.7%) to other methods. Periodontal competencies and skills were most frequently assessed by clinical grading on clinic, multiple-choice examination (written examination) and oral examination, whereas competency tests and self-assessment were rarely used. Only in 11 (14.5%) cases, access flap procedures were performed by students. CONCLUSION: Great diversity in teaching methodology amongst the surveyed schools was demonstrated, and thus, to harmonise undergraduate periodontal education and assessment across Europe, a minimum set of recommendations could be developed and disseminated by the EFP.

Evaluation of the ability of collagen-glycosaminoglycan scaffolds with or without mesenchymal stem cells to heal bone defects in Wistar rats.

PURPOSE: The aim of this experiment was to examine the capacity of collagen-glycosaminoglycan scaffolds, with or without mesenchymal stem cells, to satisfactorily repair a 5-mm rat calvarial defect. METHODS: Fifty-five Wistar rats were used in the study. The defects were either left empty to serve as controls (n = 7) or filled with cell-free scaffolds (n = 11), cell-seeded scaffolds that were pre-cultured in standard culture medium (n = 13), cell-seeded scaffolds that were pre-cultured in osteoinductive factor-supplemented medium (n = 12) or particulate autogenous bone (n = 12). The animals were sacrificed at 12 weeks after surgery, and specimens were prepared for histomorphometric analysis. The linear bone healing and the bone area within the defect were measured. RESULTS: Comparable results were obtained using cell-free collagen-glycosaminoglycan scaffolds and autogenous bone both in terms of linear bone healing (P < 0.986) and area of new bone (P < 0.846). While the test groups showed significantly more bone formation compared to the empty defect control group, the linear bone healing and area of new bone within the defect were significantly lower in the cell-seeded scaffolds than in the cell-free scaffolds. The results have demonstrated that a cell-free collagen-glycosaminoglycan scaffold is capable of repairing a 5-mm rat calvarial defect as effectively as autogenous bone and that seeding the scaffold with pre-cultured mesenchymal stem cells prior to implantation offered no beneficial effect and resulted in incomplete healing of the defect. CONCLUSIONS: The results thus suggest that the scaffold has immense potential for tissue repair showing favorable osteoconductive properties, biocompatibility and degradability.

The role of the curriculum and other factors in determining the medium- to long-term attitude of the practicing dentist towards life-long learning.

OBJECTIVES: To investigate the significance of the undergraduate dental curriculum on the medium- to long-term attitudes of the clinician to life-long learning, and to identify demographical and professional characteristics which may influence this attitude. METHODS: A specially designed questionnaire targeted 12 cohorts of dentists who qualified from Dublin Dental School and Hospital between 1994 and 2005. The curricula of the cohorts varied from fully didactic, exclusively Problem Based Learning or a hybrid for the oldest, youngest and middle graduates, respectively. Participants were questioned about current professional activities, postgraduate training, practice type, hospital affiliation, use of information services and time dedicated to continuing dental education (CDE), etc. A number of dental scenarios were proposed to determine if participants were adherent to current clinical guidelines. Additionally, a visual analogue scale assessed the overall satisfaction of dentists with their undergraduate programme and determined their opinion regarding its influence on subsequent ability to practice dentistry and keep up-to-date with scientific developments. RESULTS: Contingency analysis of the association between curriculum and continuous educational data did not produce statistical significance. Dentists who work in a hospital environment spend more time on CDE (chi(2), Pearson's, P = 0.001), are more adherent to current guidelines (chi(2), Pearson's, P = 0.005) and found their undergraduate studies more enjoyable (Wilkoxon/Kruskal-Wallis, P = 0.01). CONCLUSIONS: Undergraduate curriculum type was found to have very little or no effect on the graduate's attitude towards life-long learning or confidence in their ability to practice dentistry. However, these attitudes did appear to be influenced by certain family, demographical and professional characteristics.

Clinical teaching in restorative dentistry and the variation between students' and supervisors' perceptions of its effectiveness.

OBJECTIVES: To investigate if there was an agreement between the students and supervisors on the quality of clinical teaching in Restorative Dentistry in the Dublin Dental School and Hospital and to identify differences on how effective clinical teaching is perceived between three academic years. In addition it aimed to identify the existence of any similarities between students' and supervisors' perceptions of specific teaching behaviours that are most and least helpful in learning. MATERIALS AND METHODS: An anonymous questionnaire based on the above objectives was distributed to three cohorts of undergraduate students and three cohorts of clinical supervisors. The response rate was 94% for the first, 94% for the second and 63% for the third student cohort. Twenty-one (21) out of the 36 supervisors returned the questionnaire. Basic analysis of the clinical questionnaire was carried out in order to find the distributions of the variables between the groups. These distributions were compared using a non-parametric analysis (Kruskal-Wallis). The degree of association was measured by the Pearson's chi-square values. RESULTS: Students from all 3 years reported to be neither very satisfied nor very dissatisfied with their clinical teaching with a few statistically significant differences across the 3 years. The supervisors on the other hand, replied with a great deal of similarity across the 3 years. Furthermore, supervisors gave a high degree of straight line responses and generally felt very good about the level of clinical teaching. There was a high degree of variability in what the supervisors thought was important but also a high degree of similarity in what they thought was not helpful. It was exactly the opposite for the students. CONCLUSIONS: There is a limited agreement between students and staff on the effectiveness of clinical teaching and the way effectiveness is perceived between students and clinical supervisors as well as between senior and more junior students. Overall though students and supervisors rated the clinical teaching favourably but indicated several areas of concern.

Problem-based learning in academic health education. A systematic literature review.

Problem based learning (PBL) arguably represents the most significant development in education over the past five decades. It has been promoted as the curriculum of choice, and since its introduction in the 1960's, has been widely adopted by many medical and dental schools. PBL has been the subject of much published literature but ironically, very little high quality evidence exists to advocate its efficacy and subsequently justify the widespread curriculum change. The purpose of this review is to classify and interpret the available evidence and extract relevant conclusions. In addition, it is the intent to propose recommendations regarding the relative benefits of PBL compared with conventional teaching. The literature was searched using PubMed, ERIC and PsycLIT. Further articles were retrieved from the reference lists of selected papers. Articles were chosen and included according to specific selection criteria. Studies were further classified as randomised controlled trials (RCTs) or comparative studies. These studies were then analysed according to intervention type: whole curricula comparisons and single educational interventions of shorter duration. At the level of RCTs and comparative studies (whole curricula), no clear difference was observed between PBL and conventional teaching. Paradoxically, it was only comparative studies of single PBL intervention in a traditional curriculum that yielded results that were consistently in favour of PBL. Further research is needed to investigate the possibility that multiple PBL interventions in a traditional curriculum could be more effective than an exclusively PBL programme. In addition, it is important to address the potential benefits of PBL in relation to life-long learning of health care professionals.

Patient satisfaction relating to implant treatment by undergraduate and postgraduate dental students--a pilot study.

Recordings of patient satisfaction with provision of dental implant treatment are scarce. This study aimed to evaluate satisfaction amongst patients attending for provision of implant treatment by training undergraduate and postgraduate students at Dublin Dental School and Hospital (DDSH). A questionnaire was formulated and distributed to 100 individuals randomly selected from records of patients who had received implant treatment via student clinics in the previous 5 years. The response rate was 68%. Results showed a high overall level of satisfaction with treatment received.

Dental nursing education and the introduction of technology-assisted learning.

The aim of this paper is to explore the profile of dental nursing students in the National Dental Nurse Training Programme of Ireland and their adjustment to a technology-assisted learning environment. Evaluation by students of the course and their reactions to the course were analysed. Dental nurses must possess the skills and knowledge to proficiently function in the modern day dental surgery. The implementation of a dental nurse programme that is heavily reliant on technology has started to create a group of dental nurses equipped with basic skills to access and retrieve information over a lifetime. However, the transition to a technology-assisted learning environment including online learning activities requires adaptation and expertise by educators and students alike. Careful evaluation and stakeholder feedback is imperative in the creation and maintaining of a quality programme. In conclusion, the students in this study responded well to the transition to a technology-based learning environment. Furthermore, the findings of this study suggest that the use of an online environment is an effective and stimulating learning environment for the students of a dental nurse programme; however, familiarity skills and knowledge of information technology is a prerequisite for success.

Who is at risk? Periodontal disease risk analysis made accessible for the general dental practitioner.

The use of odds ratio (OR) in risk analysis is considered a useful means of cross-comparing risk factors by which a disease is influenced. This article outlines the interpretation of reported ORs with respect to periodontal disease, highlighting those factors that are most deserving of consideration. The claim that periodontal disease is implicated in some serious systemic diseases is investigated with respect to the evidence. Data retrieval was carried out, focusing primarily on ORs for factors shown to be positively correlated with the incidence of periodontal disease. Using the available data, a risk evaluation scoring system was proposed (the Cronin/Stassen BEDS CHASM scale). The results of the evaluation support the view that hygiene therapy, smoking cessation and control of the glycaemic state offer the largest and most easily achieved reduction in risk with respect to attachment loss. The literature on systemic diseases indicates that the mechanisms with which periodontitis may interact seem biologically plausible, compellingly so in the cases of coronary heart disease and diabetes mellitus. However, statistical evidence to confirm these suggested interactions is equivocal, with the data retrieved in some instances being less than decisive. Further investigation is recommended.

The potential impact of periodontal disease on general health: a consensus view.

BACKGROUND: Evidence for a link between periodontal disease and several systemic diseases is growing rapidly. The infectious and inflammatory burden of chronic periodontitis is thought to have an important systemic impact. Current evidence suggests that periodontitis is associated with an increased likelihood of coronary heart disease and may influence the severity of diabetes. SCOPE: This paper represents a UK and Ireland cross-specialty consensus review, undertaken by a group of physicians and dentists. The consensus group reviewed published evidence (PubMed search for review and original articles), focusing on the past 5 years, on the contributory role of periodontal disease to overall health. In particular, evidence relating to a role for periodontal disease in cardiovascular disease and in diabetes was considered. FINDINGS: Initial studies of large epidemiological data sets have sought to find links between periodontitis and systemic disease outcomes, but a causal relationship still needs to be demonstrated between periodontal disease, cardiovascular disease and diabetes through prospective studies. There is a need for prospective studies assessing the association between periodontal disease and patients at particular risk of cardiovascular events which will allow assessment of both cardiovascular disease clinical endpoints and surrogate markers of cardiovascular risk. Of note, periodontal disease is also often more severe in subjects with diabetes mellitus, a group at already increased risk for cardiovascular events. CONCLUSIONS: While further research is needed to define the population-attributable risk of periodontal disease to both cardiovascular diseases and to diabetes control and progression, health education to encourage better oral health should be considered as part of current healthy lifestyle messages designed to reduce the increasing health burden of obesity, cardiovascular disease and diabetes.

Adapting to changes in molecular biosciences and technologies.

Dental education, like any other educational programme in a research-intensive university environment, must be research led or at least research informed. In this context, as the research and knowledge base of dentistry lies in the biological and physical sciences, dental education must be led by advances in research in both these areas. There is no doubt that biotechnology and nanotechnology have, over the past 25 years, led research in both these areas. It is therefore logical to assume that this has also impacted on dental education. The aim of this paper is twofold; on one hand to examine the effects of biotechnology and nanotechnology and their implications for dental education and on the other to make recommendations for future developments in dental education led by research in biotechnology and nanotechnology. It is now generally accepted that dental education should be socially and culturally relevant and directed to the community it serves. In other words, there can be no universal approach and each dental school or indeed curriculum must apply the outcomes in their own social, cultural and community settings.

Contents of stomatological curricula in Europe.

The present study focuses on dental education in the Accession Countries to the European Union. Comparisons were made with data from EU dental schools [Eur J Dent Educ 1 (1997) 35]. The findings show a large variation in the hours allocated to individual subjects, medical and dental, both within and between AC and EU dental schools. Stomatology derived from General Medicine and the stomatologist is viewed as a doctor responsible for one part of the body. This was explained by the large proportion of time dedicated to medical subjects, especially in the first 2/3 years of the undergraduate curriculum. The percentage of hours for dental sciences varied inversely to those for bio-medical sciences and increase continuously from the first year to the final year. Curricula in the Stomatological schools tend to have a discipline-structured approach, generally utilising a large number of individual departments, resulting in a multitude of subjects being taught. Curricular extensions from 5 to 6 years were introduced in some schools from 1990 onwards in order to accommodate new dental subjects.

The influence of some different factors on the accuracy of shade selection.

The purpose of this study was to elucidate some of the factors on which accurate shade taking depends. Custom shade tabs (0.5, 1.0 and 1.5 mm porcelain thickness) were fabricated from selected Vita and Shofu porcelains. Four main factors were investigated, namely, the difference between the two types of porcelain used, the effect of light quality, the effect of porcelain thickness and the experience of the observer. The chi-square test for independence at a probability level of P <0.05 was used to analyse the results. The results indicated that in ideal light there was no difference between the two porcelains (P=0.58). The experienced observers proved better than the novice observers in ideal light conditions (P=0.003). Thickness was also significant in the overall results (P=0.0001), in that thicker samples gave more accurate results. The results indicate that in adverse light, there was an overall difference between the two porcelains (P=0.046), but no difference between the experienced and novice observers. The thickness made no difference to the experienced or the novice observer in adverse light. These results indicate that the most influential factor on shade taking was the light quality (P <0.0001); better results were obtained overall for the ideal light situation. In ideal light thicker samples gave better results (P=0.0001).

A comparison between clearing and radiographic techniques in the study of the root-canal anatomy of maxillary first and second molars.

AIM: To compare a clearing technique with conventional radiography in studying certain features of the root-canal system of maxillary right first and second molars. A secondary aim was to assess interexaminer agreement for these features using radiographs. METHODOLOGY: Eighty-three recently extracted permanent maxillary right first molars and 40 recently extracted maxillary right second molars from an Irish population were included. Standard periapical radiographs were taken from a buccolingual and mesiodistal direction. The specimens were then decoronated, demineralized in 10% hydrochloric acid for 8 days and then cleared using methyl salicylate. The cleared teeth were examined using a dissecting microscope (x20), and data relating to number of roots, canal type following Vertucci's classification, presence of lateral canals, presence of transverse anastomoses and position/number of apical foramina were collected. The radiographs were examined by two independent trained endodontists using an X-ray viewer and a magnifying lens (x2) in a dark room for the same features studied using the clearing technique. RESULTS: The Kappa values for the agreement between the radiographic examiners A and B and the clearing technique and between the two examiners for the number of roots were 0.60, 0.64 and 0.53; for the root-canal type, 0.37, 0.41 and 0.42; for the number of roots with lateral canals, 0.21, 0.18 and 0.14; and for the transverse anastomoses, 0.29 for radiographic Examiner A. Radiographic Examiner B did not feel capable of accurately recognizing transverse anastomoses from the radiographs. For the position/number of apical foramina, the Kappa values were 0.33 and 0.24, respectively. In general, the Kappa values were low to modest for all comparisons. CONCLUSIONS: It is concluded that the agreement between the two radiographic examiners and the agreement between either radiographic examiner and the clearing technique were poor to moderate, indicating the limited value of radiographs alone when studying certain aspects of the root-canal system.

Formulation and preliminary in vivo dog studies of a novel drug delivery system for the treatment of periodontitis.

A novel drug delivery system for the treatment of periodontitis was developed using two components. The first was tetracycline base loaded into the microtubular excipient halloysite, which was coated with chitosan to further retard drug release. Encapsulation efficiencies of 32.5% were achieved with the loading procedure, with tetracycline base showing in vitro release for up to 50 days in simulated gingival crevicular fluid. The second component developed was a vehicle for the drug loaded coated halloysite, which was primarily based on the thermoresponsive polymer, poloxamer 407. A concentration of 20% was chosen with the thermoresponsivity of the system modified using PEG 20,000 so that the mobile product at room temperature would gel by temperature rise following syringing into a periodontal pocket. Retention of the overall system in the pocket was further improved by the addition of octyl cyanoacrylate (OCA). The thermoresponsivity of the poloxamer 407 system proved to be sensitive to the presence of added excipients with the levels of PEG 20,000 and OCA requiring modification in the presence of the halloysite component. A final formulation was developed which consisted of 200 mg of halloysite double loaded with tetracycline base and coated with chitosan, suspended in 1 ml of poloxamer 407 20% (w/w), PEG 20,000 0.5% (w/w), OCA 1.0% (w/w), water to 100%, adjusted to pH 4. The syringeability of this formulation at various temperatures was evaluated to ensure ease of delivery to the periodontal pocket. A stability study was performed to examine the change in thermoresponsivity over time, with the final formulation found to be stable for at least 9 months when stored at room temperature (approximately 20 degrees C). This formulation offered ease of delivery to the periodontal pocket and sustained release of the antibiotic for up to 6 weeks. The formulation had preliminary in vivo testing performed in dogs to determine levels of drug release, antimicrobial activity and retentive ability of the product. A wound pocket creation model was developed for the purposes of the trial. The product was easy to deliver to the pockets with application times of less than 1 min. Results showed the product was retained in the pocket for up to 6 weeks with effective tetracycline levels released locally over this time period, which achieved good antibacterial activity.

Essential oil mouthwashes: a key component in oral health management.

This Supplement provides clear evidence that essential oil (EO) mouthwashes can be a beneficial, safe component of daily oral health routines. However, despite the wealth of supporting evidence, several issues are worthy of discussion. Patient compliance is a clear issue with oral home-care routines, and the emphasis is on dental professionals to communicate the importance of adherence. The reasons for each step of the oral-care routine (i.e. brushing, flossing, rinsing) should be clearly explained, and if required, additional motivation should be provided. Most mouthwashes contain denatured alcohol as a delivery vehicle, and some concern has been raised about the association of alcohol with oral cancer. However, a review by the Food and Drug Administration and American Dental Association found that the supporting evidence to date is inconsistent and contradictory. Some mouthwashes have a pH below 5.5, and some researchers believe that this can lead to tooth erosion. Studies have shown that although the pH of an EO mouthwash is below 5.5, salivary pH remains above 5.5 following rinsing and for 15 min postrinse.

Tensile strength, histological and immunohistochemical observations of periodontal wound healing in the dog.

This study was designed to study wound strength at the dentine/connective tissue interface and at the bone/connective tissue interface following full thickness flap surgery. Flaps of uniform dimension were outlined in four young adult beagle dogs using a standardised double bladed knife and vertical incisions 10 mm apart, which extended 8 mm apical to the gingival margin. Bone was removed from half the sites (eight sites in each dog), giving 32 flaps replaced on dentine and 32 sites on bone. A tensile force was applied using a microprocessor force gauge at 1, 2, 3, 7, 10, 14, 21, and 28 days. Mean tensile strengths were markedly weaker for the dentine/flap interface. At 7 days the value for flaps to dentine was 1.82 N, in contrast to 5.08 N for flaps replaced on bone. Inflammatory cell counts tended to fall markedly at 3 days for both modalities, but were higher for the dentine/flap modality at all time points. Fibroblast density peaked at 7-14 days but did not vary with type of flap over the time points studied. The amounts of fibrin were greater for the dentine/flap interface at all time points but decreased for both flap types as time progressed. Collagen type V was localised to the basement membrane and blood vessels and tended to show more foci for flaps replaced on dentine. Procollagen levels showed little change over the healing interval for both flap/bone and flap/dentine interfaces. Type III collagen synthesis was at peak levels during the first week. These findings would support efforts to stabilise periodontal flaps at early time points, especially those on dentine.

The effect of Nd:YAG radiation at nanosecond pulse duration on dentine crater depth.

The effect of laser parameters on laser-dentine interaction is little known. The aim of this in vitro study was to determine the effect on dentine crater depth of Nd:YAG laser radiation in relation to pulse repetition rate, total delivered energy, dentine site and the presence or absence of a dye. One hundred and forty-four sound third molars were extracted and sectioned transversely to provide 288 upper and lower cut surfaces. The upper surfaces were painted with a layer of dye (IR5) suitable for absorption at 1064 nm. The specimens were divided into 12 sub-groups each containing 12 upper and 12 lower specimens. These were exposed to a Nd:YAG laser with a 30 nanosecond (ns) pulse duration. This laser operated in a non-contact mode (spot diameter 165 microm) with pulse repetition rates of 2.5, 5.4 and 10.5 Hz. Four total energies were delivered at each repetition rate; 2.3, 3.63, 3.96, 4.29 joule (J) at 2.5 Hz repetition rate; 2.3, 2.64, 3.63, 4.29 J at 5.4 and 10.5 Hz repetition rates. Five outer and three inner sites were irradiated on each specimen. Each dentine crater depth was measured five times using a Reflex Microscope and a three-dimensional centre of gravity derived. An upper and lower specimen were taken from each sub-group and viewed under a scanning electron microscope (SEM). ANOVA was applied: total delivered energy and dyed/undyed were found to have a statistically significant effect on crater depth (p<0.0001). In general increasing energy and the presence of dye produced deeper craters. Inner/outer dentine location and repetition rate were not found to be statistically significant. All craters were carbonised.

Effect of groove placement on the retention/resistance of resin-bonded retainers for maxillary and mandibular second molars.

STATEMENT OF PROBLEM: Lack of retention/resistance form in the clinical preparation of teeth for resin-bonded retainers may lead to clinical failure. PURPOSE: This study investigated the effect of proximal grooves on the retention/resistance of cast resin-bonded retainers for maxillary and mandibular second molar teeth. MATERIAL AND METHODS: Two ivorine teeth (a maxillary and a mandibular second molar) were prepared for resin-bonded retainers. Twenty metal replicas of the prepared teeth were made (10 for each tooth morphotype). Resin-bonded retainers 0.5 mm thick were made for the 40 replicas and luted with Panavia EX cement. Forces for dislodgment of the retainers were applied along the long axes of the teeth. Forces recorded at the time of dislodgment were analyzed with 2-way analysis of variance and the post hoc Scheffé test. RESULTS: Grooves resulted in substantial increases in debonding forces for maxillary molars (P<.001). The effect of grooves on mandibular second molars was not significant (P=.13). CONCLUSION: Grooves placed in tooth preparations of maxillary molar teeth for resin-bonded retainers had a significant effect on retention/resistance. The effect of grooves on mandibular second molars was less pronounced.