Case report: A medieval case of molar-incisor-hypomineralisation.

INTRODUCTION: Molar-incisor-hypomineralisation (MIH) has been identified in recent years as a condition affecting the first permanent molars and, in some cases, the permanent incisors. Many factors have been suggested as to its aetiology. Examples of MIH have also been reported in skeletal remains in the past. These historical examples have, however, been for unknown individuals. CASE REPORT: A skull that has become available for dental examination that is uncertainly attributed to be that of Lady Eleanor Talbot (c.1436-1468) who ended her life as a Carmelite nun in Norwich (England). The dental findings of the examination showed enamel defects of molar teeth 36 and 46, as well as small areas on other molars, and striations of the enamel of permanent anterior teeth consistent with MIH. There is exposure of the roots of some maxillary teeth with resultant root caries. The presence of areas of enamel decalcification commensurate with 'Turner teeth' on 43 and 44 indicates that there were likely to have been periapical abscesses secondary to dental caries of the primary teeth. In addition, there is occlusal wear of all of teeth with extensive calculus and periodontal exposure of the roots of the mandibular incisors. Failed development or very early ante-mortem loss of premolars 15 and 25 is evident, as well as evidence in the same region of a large abscess cavity with extensive maxillary bone destruction. Healing cribra orbitalia, porosity, which is considered to be an indicator of nutritional stress, is visible on the superior aspect of the left orbit. CONCLUSION: A case of MIH is reported in a skull dating from the mid-15th century.

The conduct of dental research: the protocol, a guide.

BACKGROUND: Research today requires detailed planning to ensure efficient work, to raise funding and to fit into time constraints. AIM: The aim of this article is to provide a broad guidance on the layout and content of a research protocol. METHOD: Years of experience in writing research protocols were used to give guidance on writing, timings, content, layout and successful completion.

Submitting an application for research ethics clearance.

BACKGROUND: Research involving human subjects requires approval by a research ethics committee before commencement. What appears to many researchers to be a daunting task can be relatively easy if approached sensibly. AIM: The aim of this paper is to offer advice to potential applicants for ethics approval of their research. METHOD: The paper provides practical information, based on years of experience, for novice and experienced applicants to a research ethics committee.

Writing scientific papers for publication: "Without publication research is sterile".

BACKGROUND: The publication of basic science and clinical research findings, as well as new clinical diagnosis and treatment techniques, is widely disseminated. These days there is considerable competition to publish so the selection process is even more competitive. AIM: To present advice as to how to enhance the chances of being published and more importantly how to prepare a paper for submission. METHOD: Instructions are presented as to the steps to be taken in writing a scientific manuscript. This covers Introduction, Materials and Methods, Results and Discussion. Guidance is given as to what should be included and also what should be left out. The precision of writing is paramount and scientific text needs to be simple, easily read and translated by those whose day-to-day language is not English. Advice is given on journal selection and how to ensure the best chance of manuscript acceptance.

Congress abstracts: preparing abstracts for submission and successful acceptance.

AIM: To provide guidance on writing congress abstracts for submission and how to increase the chance of acceptance. REVIEW: There is increasing competition for submitted abstracts to be accepted by scientific congresses. Because the facilities or size of a congress may be limited a selection process is often used based upon the quality of abstracts submitted. Accordingly, it is crucial for a researcher to prepare an abstract very carefully to ensure the best chance of acceptance. The approaches to preparing an abstract and the techniques for enhancing quality are reviewed. Suggestions and guidance are given to ensure the production of a well structured, informative and scientifically sound abstract.

Reviewing scientific manuscripts.

AIM: To provide guidance on reviewing scientific manuscripts for publication. REVIEW: Scientific peer review is possibly one of the most important tasks a scientist is asked to do. It carries a great responsibility and needs to be conscientiously and thoroughly carried out. It is most important that a reviewer decides very quickly whether to undertake a review and if so to complete the task. It must at all times be objective, as positive as possible and seen as contributing to the advancement of our knowledge. This review provides suggestions as to best practice in reviewing a scientific manuscript in dentistry. The various aspects of importance: accepting or declining a review, objectivity, approaches to reading and taking notes, assessment of methods, validity and reproducibility of results and evaluating a discussion, are covered in detail and the standards that are required considered. Suggestions are made as to how a review should be reported.

What becomes of dental research trainees once they leave the Dental Research Institute? An analysis over 53 years.

The careers of 131 dental research trainees were followed (1954-2007) to establish whether and how they utilised their research training in keeping with clinical research workforce needs. The Dental Research Institute database was used to obtain trainee demographic, teaching and research outputs which were examined according to degree types: PhD (18); MSc (55); MDent (42) and dropout (16). Current careers show that 48% are in exclusive private practice and 15% in exclusive academia with further 15% practitioners having academic links via sessional teaching or research at a dental school. Most (63%) have remained in South Africa but emigration is high amongst the PhD and MSc groups. Forty-one per cent of the cohort is of age

Waviness of atraumatic restorative treatment (ART) prepared surfaces.

INTRODUCTION: The wave (W) element offers a surface topography assessment method with the potential to yield unique data. AIMS AND OBJECTIVES: This study uses glass ionomer cement specimens prepared with six Atraumatic Restorative Treatment (ART) surface treatments to explore arc- and line-modified waviness of these surfaces to determine if they gave similar results. METHODS: Six specimens (5 x 1.5mm) were prepared for each of the six surface treatments: (1) surface compressed with a Vaseline lubricated finger (Va); (2) Va followed by carving with an excavator(Ca); (3) Ca burnished with a ball burnisher (Bu); (4) surface compressed with the gloved finger lubricated with poly-acrylic acid (Aa); (5) surface cured against a Mylar strip (My); (6) My polished with a white rubber sulcus wheel (Po). After storage in distilled water for seven days at 37 degrees C W(a), W(v), W(p), W(t) was analysed using arc- and line-modifications of the raw profile. The data were analysed using a General Linear Models analysis and Tukey's Studentised range test with P < 0.05. RESULTS: Ca and Bu; Va and Aa; and My and Po formed three groups with descending ranking order for W whether arc- or line-modified. Arc-modified tracing data was unable to statistically distinguish between surface treatments whereas line-modification showed significant differences between treatments for all parameters measured (W(a), W(v0, W(p), W(t)). CONCLUSIONS: Line-modified waviness data was better able to distinguish between surface treatments than arc-modification. Wave offers unique surface topography data having potential value to dental materials researchers.

Measurement of dental restorative material topography.

INTRODUCTION: The tracing of peaks and valleys produced during surface profiling of dental materials are read against a mean line which can be modified in the form of a line or arc. Roughness (R) is commonly used to measure the topography of restorative materials, but the profile (P) value is also generated during the tracing and includes both roughness and waviness of the surface. AIMS AND OBJECTIVES: The purpose of this study was to determine if line and arc modified tracings and R and P surface topography measurements give similar results. METHODS: Thirty six cavities (5 x 1.5mm) were prepared in Perspex discs, restored with Fuji IX, a high strength glass ionomer cement, following the Atraumatic Restorative Treatment (ART) technique and the surface of six cavities were each treated as follows: press finger with vaseline (Va); press finger with polyacrylic acid (Aa); carving (Ca); burnishing (Bu); Mylar strip (My); polishing (Po). Topography was assessed using a profilometer which ran three equidistant tracings (3.6mm) on each surface giving a total of 18 readings for each treatment (n=6). The results of Ra, Rv, Rp, R, and Pa, Pv, Pp, P, for all 6 surface treatments were compared and analysed using ANOVA and Tukey's studentised range test with significance set at P<0.05. RESULTS: Within R + line, R + arc, P + line and P + arc, significant differences were apparent between treatments. Pairwise comparisons showed fewer instances of significant differences between surface treatments when R + line (1 instance of significant difference) was compared to R + arc (2). P + line showed 12 instances of significant differences between surface treatments while P + arc showed no difference. CONCLUSION: Both line and arc tracings gave similar results for R and either may be used in assessing surface roughness. The total deviation of the profile P showed more significant differences between treatments with line than with arc and may be a more sensitive tool when dealing with small sample numbers or subtle differences between surface treatments.

Does mechanical pressure force bacteria into the dentinal tubules of carious and non-carious teeth--an exploratory study.

BACKGROUND: Although many researchers have confirmed bacterial migration within dentine, no evidence was found to show whether bacteria can be easily forced into dentine during caries treatment. OBJECTIVES: This exploratory study was to see if bacteria could be easily forced into dentinal tubules of carious and non-carious teeth using hand excavation and air pressure. METHODS: Two (2) carious and ten (10) non-carious teeth were used. Class I (Black's Classification) cavities were created using rotary instruments in the non-carious teeth, while the carious teeth were excavated using hand instruments to remove the caries. The cavity of one carious tooth was etched and in the other tooth was not. Five (5) of the non-carious tooth cavities were etched, of which, one tooth was also disinfected. The remaining five non-carious teeth were not etched and included one tooth that was disinfected. Bacterial cultures of S. mutans, E. coli and Veilonella were placed in the prepared cavities and hand excavators and air pressure were used in an attempt to force bacteria down into the dentinal tubules. Thereafter, the teeth were fixed, decalcified and prepared for electron or light microscopy. RESULTS: One etched, and one etched and disinfected non-carious tooth showed bacteria in the dentinal tubules. One carious tooth (etched) showed bacterial presence in the dentinal tubules. CONCLUSION: This study shows that it is difficult to force bacteria into dentinal tubules using hand excavation (as in the Atraumatic Restorative Treatment technique) so a definitive study is not indicated.

Scientific surface roughness values for resin based materials.

INTRODUCTION: Surface roughness of dental restorative materials is most often established with the Ra value obtained using profilometry or by assessing surface topography with the scanning electron microscope (SEM). Both methods should validate each other in confirming surface roughness. AIMS AND OBJECTIVES: The purpose of this study was to compare surface roughness values obtained with a profilometer to the SEM appearance of 6 resin-based restorative materials and assess whether Ra was appropriate as a sole surface roughness measure. Methods Six 5mm diameter specimen discs of Prodigy (Pr); Z100 (Z); Compoglass F (C); Hytac Aplitip (H); Photac-Fil (Pf) and Vitremer (V) were prepared against Mylar strips and stored in distilled water for 14 days. One side of each disc was sequentially polished with Soflex discs to super fine state, the other side remained unpolished. Three surface roughness measurements were made on each surface (n=18) recording Ra, Rv, Rp and Rt values, this data was subjected to a four way ANOVA and Tukey's Studentised Range Test (p=0.05). Two unpolished and two polished discs per material were prepared for SEM, evaluated and visually grouped for surface roughness. RESULTS: Approximate ascending order of roughness was Z, Pr, H, C, V, Pf for Ra, Rv, Rp and Rt and un/polished treatment. Polishing increases surimens into a "bland" (Pr, H, Z, C) and "textured" group (Pf and V). The polished specimens gave four groups: (Pr), (Z and C), (H) and (V and Pf) of increasing surface complexity. Polishing caused surface scratching, removed the matrix, reduced or removed filler particles and exposed voids within the material. CONCLUSIONS: This study emphasises the importance of using more than one technique to assess surface roughness. Rv and Rp values should be utilised to better understand polish induced surface feature changes. Rv maximum is a better measure to identify surface defects which could affect restoration longevity.

Analysis of attendance rates at Soweto dental clinics 1995-2002.

BACKGROUND: Patient attendance rates at Soweto dental clinics increased during the year after the implementation of free primary oral health care in 1995. OBJECTIVE: This study was performed to examine if the attendance rates continued to increase between April 1995 and March 2002. MATERIALS AND METHODS: Monthly clinic records were used to record casual (pain and sepsis treatment) and booked patient attendance (restorative, prosthetic and orthodontic treatment) and number of dental operators in the nine primary health care clinics and one hospital clinic in Soweto. Data were analysed with SAS and Prism software. RESULTS: Total patient attendances in the primary health care clinics significantly increased from 6,161 in 1995 to 10,519 in 2002 (P<0.05) due to an increase in casual patients Booked patients decreased and patients treated per operator increased. In the hospital clinic the casual patient attendances decreased but booked patients significantly increased (P<0.005). CONCLUSIONS: Patient attendance rates increased between 1995 and 2002 with an increase in dental operator workload.

Marginal adaptation of mineral trioxide aggregate (MTA) compared with amalgam as a root-end filling material: a low-vacuum (LV) versus high-vacuum (HV) SEM study.

AIM: To compare the marginal adaptation of mineral trioxide aggregate (MTA) or amalgam root-end fillings in extracted teeth under low-vacuum (LV) versus high-vacuum (HV) scanning electron microscope (SEM) viewing conditions. METHODOLOGY: Root-end fillings were placed in 20 extracted single-rooted maxillary teeth. Ten root ends were filled with MTA and the other 10 root ends were filled with amalgam. Two 1 mm thick transverse sections of each root-end filling were cut 0.50 mm (top) and 1.50 mm (bottom) from the apex. Gap size was recorded at eight fixed points along the dentine-filling material interface on each section when uncoated wet (LV wet (LVW)) and dry under LV (0.3 Torr) in a JEOL JSM-5800 SEM and backscatter emission (LV dry uncoated (LVDU)). The sections were then air-dried, gold-coated and gap size was recorded once again at the fixed points under HV (10(-6) Torr; HV dry coated (HVDC)). Specimen cracking, and the size and extent of the crack were noted. RESULTS: Gap sizes at fixed points were smallest under LVW and largest under HVDC SEM conditions. Gaps were smallest in MTA root-end fillings. A General Linear Models Analysis, with gap size as the dependent variable, showed significant effects for extent of crack in dentine, material and viewing condition (P = 0.0001). CONCLUSIONS: This study showed that MTA produced a superior marginal adaptation to amalgam, and that LVW conditions showed the lowest gap size. Gap size was influenced by the method of SEM viewing. If only HV SEM viewing conditions are used for MTA and amalgam root-end fillings, a correction factor of 3.5 and 2.2, respectively, may be used to enable relative comparisons of gap size to LVW conditions.

Clinical, histological and microbiological study of hand-excavated carious dentine in extracted permanent teeth.

Changes in cultivable flora in dentine samples collected before and after hand excavation were examined in association with clinical status of the cavity surface, light microscopy and scanning electron microscopy (SEM). Thirty-five extracted permanent molar teeth with an occlusal caries lesion were excavated with hand instruments according to the atraumatic restorative treatment (ART) approach. Excavation pressure, dentine colour and consistency were recorded at the dentine-enamel junction (DEJ) prior to carious dentine removal and at the cavity floor after the final excavation; a microbiological sample of dentine was taken at both stages. Twelve restored teeth; six with positive and six with negative bacterial growth on the second sample, were selected for light microscopy and SEM. The hand-excavation removed tooth structure was soft, irreversibly damaged, dark and highly infected. Hand excavation reached dentine of increased hardness with a more normal colour to provide a sound structural base for restoration. Light and SEM examination of the cavity floor showed infected dentinal tubules in all 12 teeth examined. Linear logistic analysis showed a statistical association between light-yellow dentine on the cavity floor and an absence of bacterial growth (P = 0.006). This short-term in vitro study showed that caries-producing bacteria remained in dentine close to the cavity floor in 26/35 teeth despite clinical observations that indicated a suitably prepared cavity floor.

Mutans streptococci strains prevalence before and after cavity preparation during Atraumatic Restorative Treatment.

Critics argue that all carious dentine is not removed from the hand-prepared cavity during the Atraumatic Restorative Treatment (ART) procedure, and that the caries process is soon resumed. The aim of this study was to determine the effectiveness of ART in removing carious tissue, by investigating the numbers of mutans streptococci and lactobacilli, with emphasis on the prevalence of Streptococcus mutans and Streptococcus sobrinus strains before, and after ART treatment of dental caries. Two microbiology samples were collected. The first sample was removed from the centre of the carious lesion at the enamel-dentine junction, and the second was collected from the centre of the hard cavity wall above the pulp, after the soft infected dentine had been manually removed. A total of 71 mutans streptococci isolates from 31 children and 40 carious teeth were subcultured, biochemically characterised and genotyped by the arbitrarily primed polymerase chain reaction (AP-PCR). Results showed a significant decrease in TVC (P<0.0001), mutans streptococci (P < 0.0001) and lactobacilli (P = 0.0002) after cavity preparation. AP-PCR identified S. mutans strains that were undetectable during biotyping, and divided clinical isolates into two main clusters. In all, 63% (45/71) of isolates from the carious lesions comprised S. mutans strains. After cavity preparation, this was reduced to 35% (25/71), of which 30% (21/71) were S. mutans and the remaining 6% (4/71) S. sobrinus strains. The number of mutans streptococci strains was below detectable levels in 19 of the prepared cavities. The significant decrease in bacteria after manual cavity preparation demonstrates the reliability of a standardized ART technique, yet the presence of S. mutans strains shows that the effectiveness of the ART procedure can vary during treatment and between dental practitioners.

Airway status in civilian maxillofacial gunshot injuries in Johannesburg, South Africa.

BACKGROUND: Airway management of the maxillofacial gunshot injury constitutes a critical decision and an area that requires review in the context of civilian injuries. Most of our knowledge is extrapolated from military experience, which constitutes a different trauma patient group. This paper reports a retrospective survey of airway status in relation to maxillofacial gunshot injuries. The objective is to correlate clinical findings with treatment decisions. METHODS: A survey was done of 11,622 archived maxillofacial surgery records (1987-1992) in the three academic hospitals in Johannesburg. RESULTS: There were 211 maxillofacial gunshot injuries, for which 92 patient records had sufficient detail for inclusion in the analysis. The typical patient was a black male aged 20-29 years, shot with a low-velocity bullet of 0.38 calibre, admitted to hospital the day of the injury, operated on within 4 days, and discharged 4 days later. The airway was threatened in 20/92 cases at admission; 12/20 cases were treated with oro-or nasotracheal intubation, and 9/12 later had elective tracheostomies; 8/20 needed immediate surgical airways, 5 tracheostomies and 3 cricothyroldotomies (all later converted to tracheostomies). Three of thirty-seven patients with normal airways on admission later required emergency tracheostomy. CONCLUSIONS: An abnormal airway was significantly more likely after a high-velocity injury, and when the tongue, floor of mouth, midline or bilateral facial skeletal bones were involved.

Accurate diagnosis of occlusal carious lesions--a stereo microscope evaluation of clinical diagnosis.

This study was undertaken to validate the caries status of 214 teeth by serial sectioning and microscopy after caries diagnosis using four methods. Two hundred and fourteen extracted human teeth with varying degrees of caries were mounted in the jaws of nine training manikins. All tooth surfaces were examined and recorded for caries by four dentists using bitewing radiographs, fibre-optic transillumination (FOTI), mirror alone and a mirror and sharp probe on two separate occasions. Thereafter the teeth were serially sectioned and assessed microscopically for depth of caries lesion on a graded score of 0-7. This report assessed the diagnostic outcome of 2,183 observations for occlusal surfaces. Sound diagnoses predominated over unsound until caries was present in the inner half of dentine. Specificity was between 90% and 95% and sensitivity 26% and 50% depending on which diagnostic method was used and where the sound/unsound threshold was set. Negative and positive predictive values were similarly influenced and varied between 53% and 80% and 73% and 90%, respectively. Probit analysis showed no significant differences (P < 0.05) between examiners and diagnostic methods. Diagnosis of occlusal caries undertaken in an in vitro simulated clinical situation is inaccurate until the caries lesion extends deep into the dentine no matter which of the four methods was used.

Surface roughness of aesthetic restorative materials: an in vitro comparison.

The purpose of this study was to compare the surface roughness of three types of aesthetic restorative material. Six standard samples of two brands of each type of material were prepared namely: hybrid composites (Prodigy, Z100), compomers (Compoglass F, Hytac Aplitip) and glass ionomer cements (Photac-Fil, Vitremer) in a perspex mould (N = 36). Upper and lower surfaces were covered with Mylar strips which, in turn, were covered with glass slides and compressed to express excess material. After light curing, specimens were stored in distilled water for 14 days. Thereafter, one side of each specimen was polished sequentially with medium, fine and super fine Soflex discs (treatment). Untreated surfaces served as controls. All surfaces were examined with Talysurf and the surface roughness (Ra) of each specimen was recorded. Three measurements were made of each specimen. A 4-way ANOVA and Tukey's Studentised range test were used to analyse the data. Statistically significant effects were found for both type of material (P = 0.0001) and for treatment process (P = 0.0065). Among unpolished specimens: Compoglass F is significantly rougher than Vitremer, Z100, Prodigy and Hytac Aplitip, and compomers are significantly rougher than hybrids. Among polished specimens: Photac-Fil is significantly rougher than Z100 but does not differ from Compoglass F, Vitremer, Prodigy and Hytac Aplitip, and glass ionomers are also significantly rougher than hybrids. The smoothest surface is obtained when curing materials against a Mylar strip.

Energy and macronutrient intake in relation to dental caries incidence in urban black South African preschool children in 1991 and 1995: the Birth-to-Ten study.

OBJECTIVE: To study energy and macronutrient intake in relation to dental caries incidence among urban black South African children at the ages of 1 and 5 years. DESIGN AND SUBJECTS: Food frequency questionnaires and WHO caries diagnostic criteria were used. The study sample of 1639 urban black children with nutrition and dental information from the 1991 and/or 1995 Birth-to-Ten (BTT) Study interceptions comprised true longitudinal (n = 259) and cross-sectional (n = 1216 for 1991 and n = 164 for 1995) subjects. For the longitudinal group true dmfs (decayed, missing, filled surfaces) incidence and average intakes of energy and macronutrients between 1991 and 1995 were calculated. SETTING: South Africa. RESULTS: Median macronutrient intakes were not significantly different between the cross-sectional and longitudinal samples. Dental caries prevalences at age 1 were 1.2% and 1.5% for the cross-sectional and longitudinal samples, respectively. By age 5 these values were 60.4% and 62.2%, respectively. The median dmfs score at age 1 was 0. At 5 years this was 2 for all children and 5 for those with caries. Statistical analysis for trend at age 5 showed a significant increase in caries prevalence with increasing energy, carbohydrate and added sugar in the cross-sectional sample only. The only significant changes in dmfs scores were seen for energy and added sugar for the whole sample. The r values between log(dmfs incidence + 0.3) and the average nutrient log variables were low, and a general linear models analysis showed no statistically significant effects on log(dmfs incidence + 0.3) of any of the log nutrient variables. CONCLUSIONS: For the relationship between macronutrient intake and caries (prevalence and incidence), a cross-sectional and true longitudinal study gave similar results.

Temperatures in and around mandibular fractures.

This study measured the temperature in and around mandibular fractures in 20 anaesthetized patients. A fine calibrated thermocouple attached to a digital thermometer was used to measure temperature at the bone surface margin of a mandibular fracture and 5 and 10 mm from the fracture; within the fracture against the bone at 5, 7 and 10 mm depths and at the base of 7 mm deep biopsy cavities 5 and 10 mm distant from the fracture line immediately after biopsy, then 1 and 2 min later. On the surface the temperature was approximately 1 degrees C warmer than at the 5 and 10 mm sites distant from the fracture. Temperature reduced at the 1 and 2 min readings after the biopsy cavity cutting. This study confirmed that the surface temperature is lower than internal bone temperatures.