Root fracture and its management.

UNLABELLED: Root fractures are uncommon following dental trauma but are mostly diagnosed shortly after the injury, although occasionally at routine dental appointments. This paper presents the management of the different types of root fractures and the types of healing response suggesting the appropriate follow-up of these injuries. CLINICAL RELEVANCE: A thorough clinical examination supplemented with radiographs, vitality tests, appropriate treatment planning and subsequent follow-up of root fractured teeth can improve the prognosis for these teeth and also minimize the need for subsequent extractions. Immature teeth with root fractures have a better chance of healing compared to teeth with fully formed roots.

Electrical stimulation to clinically identify position of the lingual nerve: results of 50 subjects with reliability and correlation with MRI.

PURPOSE: Recently we described mapping of the lingual nerve clinically in patients using electrical nerve stimulation. This paper reports results of a larger study with inter- and intra-observer reliability and comparison with positional measurements from magnetic resonance imaging (MRI). METHODS: In 50 healthy participants, measurements were taken when subjects felt a tingling sensation in the tongue induced by a stimulation probe over the lingual nerve. Three positions were measured in relation to the third molar. Measurement reliability was tested for both inter-observer and intra-observer agreement and positional data of the lingual nerve measured clinically was also compared with nerve position as measured from MRI scans. RESULTS: Out of 50 participants, 96 nerves (49 = left/47 = right) were included in the study. The lingual nerve was identified in 90% (87) of this sample. The mean of height of the nerve in points A, B and C were 9.64 mm, 10.77 mm and 12.34 respectively. Inter-and intra-observer agreement was considered to be good to excellent (ICC = 0.8-0.96). Agreement between nerve mapping measured values and MRI measured values was good (ICC < 0.6). CONCLUSION: This technique may prove useful for the clinical determination of lingual nerve position prior to procedures in the third molar region.

Is the number of procedures completed a valid indicator of final year student competency in operative dentistry?

Introduction Concerns regarding the preparedness of dental graduates often focus on the number of procedures undertaken before qualification.Aims To assess the validity of numerical requirements in determining whether a student has sufficient competency to graduate.Materials and methods In total, 50,821 observations of student activity while on the restorative clinic, for two integrated student cohorts (n = 139), were continuously recorded using the LiftUpp system from their third year to graduation. Analysis of data determined the most frequent type, location and difficulty of the direct restorations provided.Results Four groups of students, categorised by the total number of restorations they provided, were identified. Those with the most restorations (70+) had a statistically significantly greater experience in restoring different tooth surfaces, in different quadrants, on different patients than those with the least (40-49). However, increased numbers did not correlate with increasing difficulty, suggesting that students simply became more adept at easier procedures.Discussion Using a derived measure of 'consistency', it was observed that increased performance consistency was not correlated with greater overall experience. Furthermore, only 4% of students were 100% consistent in their performance in their final year.Conclusions These data suggest that a 'numerical requirements' approach cannot be used, in isolation, as a valid measure of the competency of an individual. Further work is needed to validate consistency as a holistic measurement to characterise the performance of graduates.

Dental Pain: Dentine Sensitivity, Hypersensitivity and Cracked Tooth Syndrome.

Dentine hypersensitivity is a frequently encountered patient complaint that can present with a number of associated factors including erosion and abrasion. the hydrodynamic mechanism responsible for dentine hypersensitivity is intimately related to the anatomical and physiological composition of teeth. Alterations to the integrity of the enamel and dentine through processes of trauma, decay and toothwear can increase dentine permeability. This gives rise to symptoms of sensitivity as dentinal fluid movement in response to thermal, chemical and mechanical cues stimulate the pulpal Aδ fibres. Restorative procedures can also rapidly change the architecture of the protective enamel and dentine layers leading to pulpal inflammation and increased thermal sensitivity of the tooth.
Patient-reported symptoms of dentine hypersensitivity can be attributed to a number of possible causes and a definitive diagnosis can therefore be difficult. A full history including social and medical factors such as occupation, diet and/or medication is likely to provide significant information to aid a diagnosis. Consideration of occlusal factors should not be overlooked as these may contribute to symptoms arising from a cracked tooth.
Management strategies are linked to the diagnosis - from topically applied desensitising pastes and resin bonding agents to direct restorations and possibly more advanced restorative procedures such as root canal treatment. Management should, however, be staged to enable more conservative strategies to prevail prior to considering irreversible dental interventions.

Improving the quality of clinical teaching in a restorative clinic using student feedback.

INTRODUCTION: A large proportion of the undergraduate curriculum is spent within Restorative Dentistry at the University of Liverpool. As well as supportive "phantom head" courses the undergraduates receive significant amounts of teaching within the clinics themselves. In 2004, to help inform the clinical tutors as to their areas of strengths and weaknesses, undergraduates were invited to complete an anonymous questionnaire on the quality of teaching they received from their clinical supervisors. This process has been repeated subsequently in 2005 and 2006. METHOD: A 19 parameter questionnaire, employing a 5-point Likert scale and space for open comments, was circulated to every clinical undergraduate student. Questionnaires were returned anonymously and all data collected by one researcher. Descriptive statistical analysis was performed and the staff provided with individual feedback within the context of the overall departmental profile. The pooled data from each of the years was then compared to determine if any changes had occurred. Statistical analysis used Kruskal Wallis tests to determine whether these were statistically significant. RESULTS: Although the range varied, median scores of 4 (agree) were gained for each question each year. Following statistical analysis 18 of the parameters showed a statistically significant improvement (P < 0.05) between 2004 and 2006 with only one remaining constant throughout. CONCLUSION: It would appear that the use of a questionnaire based feedback system can result in a tangible and demonstrable improvement in the delivery of clinical teaching.

The use of confocal microscopy to assess surface roughness of two milled CAD-CAM ceramics following two polishing techniques.

OBJECTIVE: To assess the effects of two polishing techniques on the surface roughness of a commercial and experimental dental ceramic for use in a chairside CAD-CAM system. METHODS: A standard onlay was reproduced fifteen times in each of the two materials. Each stub was retained and examined using confocal microscopy in reflection mode. Five random samples of each were polished with Sof-Lex aluminium oxide discs, five polished with diamond impregnated polishing wheels and five left in the as-machined state. Surface roughness parameters were measured for each material group in each condition and statistical analyses carried out to determine the efficacy of the polishing techniques for each material. RESULTS: The as-machined surfaces of both materials had a statistically similar surface finish. Polishing with Sof-Lex discs was effective at reducing surface roughness of both materials. Whilst the polishing wheels were effective in reducing surface roughness for the commercial material, there was no statistically significant difference in the surface roughness of the experimental material in the as-machined or wheel polished states. SIGNIFICANCE: Although Sof-Lex discs were effective in reducing surface roughness of the two materials examined in this study, wheel polishing should not be used to reduce surface roughness of the experimental material. This will need to be taken into consideration in any future clinical studies of this material.

An investigation of the constituent elements and modes of fracture of in vivo fractured metallic posts.

OBJECTIVES: The objective of this investigation was to determine the materials used in metallic post and core construction and investigate and the modes of failure that occurred resulting in post fracture. METHODS: Eighty-five fractured metal posts were clinically retrieved over a 5-year period. The tooth with the fractured post, and relevant clinical details were recorded. Investigation of the fractured posts was undertaken to determine their constituent elements and modes of fracture using scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX). RESULTS: The results showed that 77% of the posts were cast and 23% wrought. The modes of fracture were ductile (67%) or brittle (52%) although some posts exhibited both within the same specimen. In addition, evidence of fatigue was present in 20% of posts and porosity in 48%. CONCLUSIONS: A large variety of materials were used in the construction of post and cores although low-gold silver-palladium alloy most commonly encountered. Their failure was predominantly ductile in nature although a significant amount of brittle fracture was also noted. Porosity within castings also appeared to be a contributory factor in some cases and this was particularly evident in high-palladium castings. Evidence of fatigue was noted in a minority of posts.

Thermal conductivity through various restorative lining materials.

OBJECTIVES: Traditional teaching has advocated the placement of insulating materials under restorations to protect against 'thermal shock'. Often this involves placement of a thick zinc-oxide eugenol cement lining. The purpose of this in vitro study was to assess the heat transfer through four lining materials and dentine and to relate these findings to the temperature exposures that may be experienced in the oral environment. METHODS: Two 'traditional' linings, zinc oxide eugenol cement (ZNOE) and calcium hydroxide paste (CAOH), and two more contemporary materials, a resin modified glass polyalkenoate (RMGP) and dentine bonding system (DBS) were studied in addition to dentine itself. Seven samples of each material were tested by utilising a Lees' Disc apparatus. Incorporation of thermocouples allowed heat transfer through the sample to be recorded. Thermal conductivity (J/m/s/ degrees C) was calculated for individual samples and a mean value obtained for each material. One way ANOVA and post hoc Tukey's tests were applied to the data obtained. RESULTS: In ascending order of thermal conductivity, DBS

An in vitro evaluation of resonant frequency analysis to measure fixed bridge stability.

OBJECTIVES/AIMS: To determine whether a clinically available resonance frequency analysis (RFA) device (Osstell Mentor), designed to assess implant integration, could identify a single uncemented retainer on fixed-fixed bridges, in vitro. MATERIALS AND METHODS: All-metal fixed-fixed bridges were cemented to acrylic tooth analogue abutments with simulated periodontal ligaments. Dental stone bases provided 100 or 50% 'bone support' groups (n = 50 in each). Control groups had both retainers cemented, whereas the test groups had the 'premolar' uncemented, mimicking clinical failure. A RFA device was used to measure bridge stability, expressed as a modified Implant Stability Quotient (Bridge Stability Quotient-BSQ) from a Smartpeg temporarily affixed to the bridge via composite. RESULTS: The BSQ recorded at the premolar site in both 100 and 50% support models demonstrated highly statistically significant differences (P <0.003) between the control and test groups. Sensitivity and specificity, area under the curve (receiver operating characteristic), analyses showed moderate test accuracy (0.735) for the 100% support group and good accuracy (0.96) for the 50% support group. CONCLUSION: The investigation suggests that RFA measurements were able to identify, reliably and non-destructively, in vitro, fixed-fixed bridges where the anterior retainer was uncemented. Further clinical research is required to determine whether this technique may allow early diagnosis of failing bridgework.

An in vitro study of dentin exposure during resin-bonded fixed partial denture preparation.

OBJECTIVES: The aim of this in vitro study was to investigate whether dentin is exposed during tooth preparation for resin-bonded fixed partial dentures and, if so, to quantify the amount of dentin exposure. METHOD AND MATERIALS: Twenty extracted premolars were prepared in the following manner: The palatolingual and proximal axial surfaces were reduced by 0.50 mm. Mesial and distal grooves, 1.00 mm in depth, and mesial and distal occlusal rest seats, measuring 2.00 mm buccolingually x 1.50 mm mesiodistally x 1.00 mm deep, were prepared. The specimens were stained with a modified van Gieson's stain to identify dentin exposure, mounted on a jig to allow standardization, and photographed after 30-degree rotation to create a panoramic image of each tooth. The image was modified and analyzed to measure the percentage of the preparation area that exhibited dentin exposure. RESULTS: Dentin exposure was noted in all specimens. The mean area of dentin exposure was 11.06 mm2 (16.15% of the preparation area). The minimum and maximum areas of dentin exposure were 4.07 mm2 (7.03%) and 19.73 mm2 (27.28%), respectively. CONCLUSION: Dentin is exposed during resin-bonded fixed partial denture preparation if current tooth preparation guidelines are followed, despite the commonly made recommendation that the preparation remain within enamel. The region of the grooves consistently exhibited exposed dentin; exposure at the cervical margin was variable.

An in vitro study of coronal microleakage around bonded amalgam coronal-radicular cores in endodontically treated molar teeth.

OBJECTIVE: The aim of this study was to compare the coronal microleakage of conventional and bonded amalgam coronal-radicular (Nayyar) restorations on endodontically treated molar teeth, because coronal seal is a major factor in the long-term success of endodontic treatment. METHOD AND MATERIALS: Forty extracted human molar teeth were root-filled and prepared for coronal-radicular amalgam restorations. Four groups of 10 teeth were restored with Tytin amalgam and Vitrebond, Superbond D Liner II, Panavia 21, or no adhesive agent. The teeth were placed in India ink for 1 week, and then demineralized and rendered transparent. The ink penetration was assessed with a coded scoring system. RESULTS: The bonded amalgam groups produced significantly less leakage than did the nonbonded group. No statistically significant differences in leakage were detected among the bonded amalgam groups. CONCLUSION: To prevent the reinfection of the endodontically treated molar, it may be preferable to restore the tooth immediately after obturation by employing a bonded amalgam coronal-radicular technique.

Occlusal changes following posterior tooth loss in adults. Part 2. Clinical parameters associated with movement of teeth adjacent to the site of posterior tooth loss.

PURPOSE: Much anecdotal evidence is available on tooth positional changes following loss of an adjacent tooth, but only a few studies are available. In Part 1 of this series, supraeruption was assessed and Generalized Linear Models were made to determine the clinical parameters associated with the supraeruptive process. The models demonstrated that clinical parameters were not only associated with the extent of supraeruption, but also with the type of eruption present. This investigation of tooth positional changes adjacent to sites of posterior tooth loss attempts to provide increased understanding of the magnitude, direction, and associated features that may be helpful in decision making and treatment planning in the clinical setting. MATERIALS AND METHODS: One hundred patients with an unopposed posterior tooth, with 100 age, sex, and bone level matched controls, were drawn from patients undergoing routine restorative care at Leeds Dental Institute. Study models were scanned, and the extent of eruption, type of eruption of the unopposed tooth, the overbite, overjet, buccal occlusion, and degree of crowding in the dentition, tipping, rotation, and buccal movement of the teeth associated with the edentulous site were recorded. Generalized Linear Models were developed to examine associations between each tooth movement and patient or dental factors. RESULTS: A statistical significance in the degree of tipping of teeth both mesial and distal to the extraction site was detected between the subject and control groups. There was also a significant difference in rotation of the tooth mesial to the site. Four Generalized Linear Models were produced of the types of non-vertical movements found in teeth associated with sites of tooth loss. CONCLUSIONS: Teeth adjacent to the site of tooth loss may undergo non-vertical movements. Teeth mesial to the extraction site had a tendency to tip distally. The degree of tipping was increased in upper teeth and in subjects with a cusp-to-cusp buccal occlusion. Rotation of teeth mesial to the extraction site was more prevalent in the lower arch. Tipping of the tooth distal to the extraction site could be extreme and was found to be more prevalent in subjects with a reduced (Code 1) overbite and in the lower arch. Rotation of teeth distal to the extraction site was greater in the upper arch and was also associated with a reduced (Code 1) overbite. It also had an association with rotation of the tooth mesial to the extraction site. Models of non-vertical movement are likely to be of limited value due to overdispersion, indicating a high degree of variability within the model.

Occlusal changes following posterior tooth loss in adults. Part 1: a study of clinical parameters associated with the extent and type of supraeruption in unopposed posterior teeth.

PURPOSE: One of the barriers to restoring an edentulous space may be the supraeruption of an unopposed tooth to occupy some or all of the space needed for prosthetic replacement. The aim of this study was to determine the extent and type of supraeruption associated with unopposed posterior teeth and to investigate the relationship between these and oral and patient factors. MATERIALS AND METHODS: Diagnostic casts of 100 patients with an unopposed posterior tooth and of 100 control patients were scanned and analyzed to record the extent of supraeruption, together with other clinical parameters. The type of eruption present was defined for each subject as Periodontal Growth, Active Eruption, or Relative Wear. Generalized Linear Models were developed to examine associations between the extent and type of supraeruption and patient or dental factors. The extent of supraeruption for an individual was modeled to show association between the degree of supraeruption and clinical parameters. Three models were produced to show associations between each type of supraeruption and clinical parameters. RESULTS: The mean supraeruption for subjects was 1.68 mm (SD 0.79, range 0 to 3.99 mm) and for controls, 0.24 mm (SD 0.39, range 0 to 1.46 mm). The extent of supraeruption was statistically greater in maxillary unopposed teeth than in mandibular unopposed teeth. Supraeruption was found in 92% of subjects' unopposed teeth. CONCLUSIONS: A Generalized Linear Model could be produced to demonstrate that the clinical parameters associated with supraeruption are periodontal growth, attachment loss, and the lingual movement of the tooth distal to the extraction site. Three types of supraeruption, which may be present singly, or in combination, can be identified. Active eruption has an association with attachment loss. Periodontal growth has an inverse association with attachment loss, is more prevalent in younger patients, in the maxilla, in premolars, and in females. Relative wear has an association with increasing age and is more prevalent in unopposed mandibular teeth.

Tooth surface loss: does recreational drug use contribute?

OBJECTIVE: This pilot study was designed to measure tooth wear in a sample of 13 subjects who regularly use amphetamine-like drugs (Ecstasy, amphetamines) and compare the observed wear with a matched sample of nondrug users. DESIGN: The two groups, both composed of 13 undergraduate students, were matched for age and sex. Other factors influencing tooth wear were controlled by matching the groups on their responses to a questionnaire asking about recognised common causes of tooth wear. The participants teeth were examined and the degree of wear scored according to a tooth wear index. RESULTS: Severity of occlusal tooth wear of the lower first molar teeth was significantly greater in the drug user group than in the control group (P<0.05). No other statistically significant differences between the groups were found. CONCLUSION: Regular use of amphetamine-like drugs could be associated with increased posterior tooth wear.