Long-term stability of limiting nasal alar base width changes with a cinch suture following Le Fort I osteotomy with submental intubation.

The aim of this study was to assess the effectiveness of the nasal alar base cinch suture following Le Fort I osteotomy at long-term follow-up. One hundred and forty participants (89 female, 51 male) aged between 16 and 51 years underwent Le Fort I osteotomy with submental intubation. Anthropometric measurements of the nose were taken intraoperatively, immediately postoperative, and for up to 3 years postoperative: the maximum lateral convexity of the alae (Al-Al) and the lateral extremity of the alar base curvature at the alar groove (Ac-Ac). The use of a cinch suture was recorded. The results were analysed using a linear mixed-effects model analysis. One hundred and six participants had cinch sutures and 34 had no cinch sutures. Following Le Fort I osteotomy, there were significant increases in Ac-Ac (by 4.29mm) and Al-Al (by 3.70mm) (both P<0.0001). Cinch sutures significantly reduced the widths back to preoperative values (P<0.0001). Alar width remained stable over 3 years, with an increase of 0.36mm for Al-Al (P>0.05) and 1.03mm for Ac-Ac (P<0.05) compared to the postoperative measurement. In conclusion, a cinch suture was helpful in reducing the unwanted alar base width changes, which were found to be relatively stable at 3 years.

The utility of molecular diagnostics to predict recurrence of head and neck carcinoma.

BACKGROUND: Locoregional recurrence is the major cause of treatment failure after surgery for oral squamous cell carcinoma. Molecular diagnostics have the potential to improve on clinicopathological parameters to predict this recurrence and plan adjuvant treatment. The test most frequently applied is based on detecting TP53 mutations, but alternative methodology is required for cases that harbour the wild-type gene. METHODS: One hundred and two cases with tumour-adjacent margins, considered to be clear margins by microscopy, were examined using carefully optimised molecular diagnostics based on detection of the TP53 and Ly-6D markers. The markers were also combined to provide a dual approach. RESULTS: The dual molecular diagnostic identified cases with a significant increase in the probablility of developing locoregional recurrence when tumour-adjacent positive and clear margins were compared (P=0.0001). These tests were most useful when the clearance at the resection margins was 5 mm or less. The TP53-based diagnostic was a better predictor of locoregional recurrence than established clinicopathological parameters. CONCLUSION: The optimised TP53-based diagnostic rapidly identifies an important subgroup of cases with close margins that will benefit from new treatment modalities to reduce the risk of recurrence.

Changes in centring and shaping ability using three nickel­titanium instrumentation techniques analysed by micro-computed tomography (µCT).

AIM: To compare the centring ability and the shaping ability of ProTaper (PT) files used in reciprocating motion and PT and Twisted Files (TF) used in continuous rotary motion, and to compare the volume changes obtained with the different instrumentation techniques using micro-computed tomography. Methodology Sixty mesial canals of thirty mandibular molars were randomly assigned to three instrumentation techniques: group 1, canals prepared with the PT series (up to F2) (n = 20); group 2, canals prepared with the F2 PT in reciprocating motion (n = 20); group 3 canals prepared with the TF series (size 25) (n = 20). Teeth were scanned pre- and postoperatively using micro-computed tomography to measure volume and shaping changes, and the obtained results were statistically analysed using parametric tests. Results The increase in canal volume obtained with the three instrumentation techniques was not significantly different. Canals were transported mostly towards the mesial aspect in the apical- and mid-third of the roots, and towards the furcal aspect coronally. No difference in the transportation and centring ratio was found between the techniques. There was no significant difference between the times of instrumentation (TF: 62.5 ± 5.4 s; PT: 60.6 ± 3.9 s; and F2 PT file in reciprocating motion: 51.0 ± 3.3 s). Conclusions ProTaper files used in reciprocating motion and PT and TF used in continuous rotary motion were capable of producing centred preparations with no substantial procedural errors.

Grading oral epithelial dysplasia: analysis of individual features.

BACKGROUND: Assessing epithelial dysplasia to predict malignant transformation remains problematic in many tissues because grading systems are poorly structured and individual features poorly defined. Dysplasia grading is criticised for lack of reproducibility and poor predictive value. Grading systems for upper aerodigestive tract dysplasia have evolved over several decades and are not supported by good outcome experimental data. METHODS: This study analysed the individual features of dysplasia in 86 oral dysplastic lesions and determined the reproducibility of scoring for each, and correlated them with other features and clinical factors using complex clustering analyses. RESULTS: A uniform pattern of dysplasia was found in 37 lesions, focal dysplasia in 36 and in 13 lesions dysplasia formed complex discontinuous patterns. There was wide variation in reproducibility of scoring of individual features and many, including thickness, some types of rete morphology, basaloid cell anisonucleosis, basal dyscohesion, and dyskeratosis as deep single cells correlated with sub-sites. Rete morphology, type of keratinisation, hyperchromatism of the basaloid compartment, prickle cell anisonucleosis and extension down salivary ducts correlated with smoking. Conventional grading and oral intraepithelial neoplasia (OIN) grading by 'thirds affected' showed strong correlation overall but scores obtained with the OIN system tended to a higher grade at all sites except soft palate/fauces. There was poor correlation between the systems for moderate dysplasia and also severe dysplasia at some sites. Individual features could not be shown to cluster to form distinct patterns of dysplasia. CONCLUSIONS: These variations may account in part for the lack of reproducibility and poor predictive value of the grading systems in current use and could inform the design of future grading systems.

Hand and nickel-titanium root canal instrumentation performed by dental students: a micro-computed tomographic study.

The aim of this study was to evaluate root canals instrumented by dental students using the modified double-flared technique, nickel-titanium (NiTi) rotary System GT files and NiTi rotary ProTaper files by micro-computed tomography (MCT). A total of 36 root canals from 18 mesial roots of mandibular molar teeth were prepared; 12 canals were prepared with the modified double-flared technique, using K-flexofiles and Gates-Glidden burs; 12 canals were prepared using System GT and 12 using ProTaper rotary files. Each root was scanned using MCT preoperatively and postoperatively. At the coronal and mid-root sections, System GT and ProTaper files produced significantly less enlarged canal cross-sectional area, volume and perimeter than the modified double-flared technique (P < 0.05). In the mid-root sections there was significantly less thinning of the root structure towards the furcation with System GT and ProTaper (P < 0.05). The rotary techniques were both three times faster than the modified double-flared technique (P < 0.05). Qualitative evaluation of the preparations showed that both ProTaper and System GT were able to prepare root canals with little or no procedural error compared with the modified double-flared technique. Under the conditions of this study, inexperienced dental students were able to prepare curved root canals with rotary files with greater preservation of tooth structure, low risk of procedural errors and much quicker than with hand instruments.

Delay in diagnosis and its effect on outcome in head and neck cancer.

We examined the records of two cohorts of patients who were seen from 1960 to 1999 with a diagnosis of squamous cell carcinoma (SCC) of the mouth and throat, one series being retrospective (n=400) and the other prospective (n=213) to find out about delays in diagnosis. The median delay in both cohorts was 3 months and the patients were responsible for the delay in most cases (n=319, 81% and n=160, 78%, respectively). Half the patients in each cohort had delayed diagnoses (n=217, 54% and n=119, 56%, respectively) and similar percentages (n=110, 53% and n=172, 47%) presented with advanced disease (stage III or IV). These were not the same patients for there was no correlation between delay and stage or survival. Logistic regression analysis showed that non-white race (p=0.01) and high-grade histology (p=0.002) predicted advanced disease. The proportion of patients presenting with advanced disease had not changed in 40 years despite public education. We suggest that some tumours may be silent and that initial symptoms do not reliably predict early disease.

The survival of resin modified glass ionomer and stainless steel crown restorations in primary molars, placed in a specialist paediatric dental practice.

AIMS: To prospectively report on the survival of resin-modified glass ionomer cement (RMGIC), photac-fil and pre-formed stainless steel crown (SSC) restorations in primary molar teeth placed over a seven-year period in a specialist paediatric dental practice under private contract of remuneration. METHOD: All primary molar restorations placed by a specialist paediatric dentist over a seven-year period were reviewed and the outcome results recorded. Data were recorded at review visits until June 30, 2003. Data recorded included Class I restorations, Class II restorations and SSC. The Class II cavities were either mesial or distal, with or without buccal/palatal extensions. If both proximal surfaces were decayed or if after cavity preparation the resultant outline form was significantly larger than the minimal classical form, RMGIC was not used; an SSC was placed instead. Stainless steel crown preparation followed conventional guidelines. The crowns were cemented with reinforced zinc oxide and eugenol (Kalzinol). The status was recorded as satisfactory restoration, tooth exfoliated, tooth extracted for orthodontic reasons with the date of extraction, or needing replacement. If replaced then the reason for replacement was also recorded. RESULTS: A total of 544 Class I RMGICs, 962 Class II RMGICs, and 1,010 SSCs were placed. At the last review of each restoration, 98.3% of Class I, 97.3% of Class II RMGICs and 97.0% of SSCs were either satisfactory or withdrawn intact. CONCLUSION: Under the conditions of private specialist practice-based study SSCs continued to prove very successful for the restoration of larger cavities and for pulp-treated primary molar teeth. For the smaller cavities RMGIC were also very successful.

Dolphin Imaging Software: an analysis of the accuracy of cephalometric digitization and orthognathic prediction.

The purpose of this study was to examine and compare the reproducibility and reliability of digitization using Dolphin Imaging Software (Version 8.0) with traditional manual techniques. In addition, orthognathic prediction was compared with actual outcomes. Sixty lateral cephalograms were evaluated by two methods: manual tracing and indirect digitization using Dolphin Imaging Software (Version 8.0). Method error (reliability) using duplicate measurements for each method, and comparison of both techniques (reproducibility), were investigated using alternative statistical methods, Bland and Altman (1986) and Lin's Correlation of Concordance (1989). Each technique was significantly reliable at the 95% level (method error). Comparing the standard deviations of the differences, manual tracing proving more reliable for SNA (1.36 degrees manually, 2.07 degrees digitally), SNB (1.19 degrees and 1.69 degrees ), SNMx (1.39 degrees and 2.66 degrees ), and MxMd (1.77 degrees and 2.26 degrees ), and Dolphin digital tracing more reliable for UIMx (3.49 degrees digitally and 3.97 degrees manually) and LIMd (2.90 degrees and 3.04 degrees ). However, systematic error in the software's calculation of LAFH% resulted in measurements 4% larger than manual techniques, a difference which is clinically significant. Comparison of actual outcome and software generated prediction for 26 orthognathic cases demonstrated clinically significant differences for all measurements (rhoc 0.32 for ANB to 0.91 for LIMd; P<0.05). The investigation revealed the impact of radiographic magnification when used in an uncalibrated system. These findings indicate that Version 8.0 of Dolphin Imaging Software needs to be re-assessed for software errors that may result in clinically significant miscalculations, and to facilitate compensation of radiographic magnification when using linear measurements.

Heterogeneity, histological features and DNA ploidy in oral carcinoma by image-based analysis.

Oral squamous carcinomas appear heterogeneous on DNA ploidy analysis. However, this may be partly a result of sample dilution or the detection limit of techniques. The aim of this study was to determine whether oral squamous carcinomas are heterogeneous for ploidy status using image-based ploidy analysis and to determine whether ploidy status correlates with histological parameters. Multiple samples from 42 oral squamous carcinomas were analysed for DNA ploidy using an image-based system and scored for histological parameters. 22 were uniformly aneuploid, 1 uniformly tetraploid and 3 uniformly diploid. 16 appeared heterogeneous but only 8 appeared to be genuinely heterogeneous when minor ploidy histogram peaks were taken into account. Ploidy was closely related to nuclear pleomorphism but not differentiation. Sample variation, detection limits and diagnostic criteria account for much of the ploidy heterogeneity observed. Confident diagnosis of diploid status in an oral squamous cell carcinoma requires a minimum of 5 samples.

The national survey of adverse reactions to dental materials in the UK: a preliminary study by the UK Adverse Reactions Reporting Project.

OBJECTIVE: Dental treatment involves the use of a wide range of materials. Many of the dental materials or their components pose a potential risk to the patient and member of the dental team. Pre-market biocompatibility testing cannot guarantee absolute safety, making monitoring of materials likely to cause an adverse reaction essential. The prevalence of adverse reactions to dental materials amongst dental patients and staff has not been systematically monitored in the UK. This project aims to develop a systematic approach to the evaluation and monitoring of the extent and severity of adverse reactions to dental materials in the UK. METHOD: Through the distribution of reporting forms to dental surgeries and laboratories in the UK, the ARRP has received 1,075 complete reports relating to adverse reactions seen or experienced by dental staff and patients. RESULTS: The main findings were that different materials cause adverse reactions to different groups of people. The largest proportion of patient related adverse reactions were reported to be due to metals (n = 175). These were mainly amalgam associated oral lichenoid reactions (n = 124). Dental technicians reported acrylic resin as the causal factor of hand dermatitis in 61% (44 out of a total 72) of cases reported. Finally, dental surgery staff reported gloves as causing hand dermatitis in 75% of cases (398 out of a total 531). CONCLUSIONS: Different dental materials affect different person groups depending on their exposure to the material. Dental staff are most at risk from an adverse reaction to latex gloves, whereas most reported reactions for patients were due to metals. For dental technicians the biggest danger of an adverse reaction was from acrylic resins. There is a need to continue to raise the awareness among dental professionals of the existence of the Adverse Reactions Reporting Project so as to overcome problems of under-reporting.

An in vivo and ex vivo study to evaluate the use of a glass polyphosphonate cement in orthodontic banding.

The purpose of this study was to examine the effectiveness of a new glass polyphosphonate cement (Diamond) for orthodontic banding. Thirty-one subjects underwent in vivo testing to compare the failure rate of bands cemented using the test cement and bands cemented using a conventional glass polyalkenoate cement (Ketac-Cem) over a 6-month period at the beginning of active appliance therapy. In an ex vivo experiment 60 extracted teeth were banded using either the test cement or a glass polyalkenoate cement, and subjected to a debanding force using a Lloyd universal testing machine until failure. In the in vivo study the overall proportion of failure of the bands cemented with each cement was identical at 0.048. However, in the ex vivo study the probability of failure for the glass polyphosphonate cement was significantly higher than for the glass polyalkenoate cement, and the force to deband the glass polyalkenoate cement was greater than that of the glass polyphosphonate cement. In the clinical setting the new glass polyphosphonate cement performed as well as a conventional glass polyalkenoate cement, and these results suggest that it could be used as an alternative cement for orthodontic banding. The results of the ex vivo test bring into question the usefulness of this laboratory test as an indicator of clinical performance.

Operator agreement in the use of a descriptive index of edentulous alveolar ridge form.

CAWOOD & HOWELL have proposed a classification of the anatomical form of the residual alveolar processes of edentulous patients. The purpose of this study was to test observer agreement in the clinical assessment of edentulous alveolar ridge form using this classification. This was tested in a pilot study involving 57 edentulous patients, and subsequently in a study of 557 edentulous patients. High levels of observer agreement were found when using this classification for upper and lower edentulous alveolar ridges, suggesting that the classification may be useful as a research tool.

Expression of CD44 variant exons by primary and metastatic oral squamous carcinomas.

Abnormal CD44 expression in many neoplasms correlates with behaviour, but reports on its role in oral squamous carcinoma are contradictory. CD44 expression was characterised in a closely matched series of oral carcinomas with and without metastases in both frozen and formalin-fixed tissue and correlated with behaviour and histological grading parameters. Eleven primary oral squamous carcinomas without metastases and nine primary carcinomas with 19 matched metastases were stained immunocytochemically for CD44H and products of variant exons v3, v4/5, v6 and v9. Patterns of staining in frozen and formalin-fixed tissue were correlated with invasive front grading and behaviour using exact inferential statistics. Most primary carcinomas stained for all exons tested but some showed loss of expression of v4/5. Loss of expression was more marked in metastases, but there was no correlation between expression and behaviour or grade. Stromal surfaces of epithelial cells often expressed variant exon products reflecting loss of polarity. This, together with selective loss of v4 and v5 in primary carcinomas and their more frequent loss in metastases, suggests that CD44 may play a role in metastasis of some oral squamous carcinomas.

The effect of environmental factors on elastomeric chain and nickel titanium coil springs.

It is well known that elastomers exhibit viscoelasticity and as such have their mechanical properties modified by temperature. Nickel titanium archwires are also affected by temperature and have been modified with specific temperature related properties for clinical use. What is less well known is the effect that other environmental factors, such as food, might have on the force delivery properties of both elastomeric materials and nickel titanium coil springs used for space closure. For instance gross colour change in elastomeric chain is a common clinical finding in patients who consume spiced foods. The aim of this work was to determine the effect three common environmental factors namely, water, Coke, and turmeric solution have on elastomeric chain and nickel titanium coil springs. In addition, it was decided to re-examine the effect of temperature at 10, 22, and 37 degrees C on both these space closing materials. Unlike many previous investigations, the test specimens were held at a constant stretch throughout the test period, including during their transfer to the Instron Universal Testing machine for force measurement. Six force measurements were made over the first hour, then at 24 hours and 7 days. A control group of dry specimens, maintained at 22 degrees C, had additional measurements made weekly for a 4-week period. The results indicated that elastomeric chain was affected by all the test environments while nickel titanium springs were only affected by temperature.

Factors associated with the presence of denture related stomatitis in complete denture wearers: a preliminary investigation.

Various factors have been associated with the presence of denture related stomatitis. These include local factors such as continuous denture wear, trauma from dentures and poor denture hygiene Systemic factors, use of various pharmacological agents and smoking have also been implicated. This investigation involved history taking and examination of 250 patients attending Guy's Hospital for the construction of complete dentures. No association was found between systemic factors, use of pharmacological agents or smoking and the presence of denture related stomatitis. Night wear of complete dentures was found to be significantly associated with the prevalence of denture related stomatitis.

The relationship between pure tone thresholds and the radiological dimensions of acoustic neuromas.

A retrospective analysis of 109 consecutive patients presenting with acoustic neuromas between 1986 and 1997 were undertaken. Sufficient data were available in 104 cases for comparison. In 65 cases patients had undergone surgery and the radiological diagnosis of acoustic neuroma was confirmed histologically. In this group there were 25 large and 40 small tumors when a maximal radiological diameter of 2.5 cm was used to subdivide the groups. When pure tone thresholds were compared at specific frequencies, in those with hearing ears, there was no significant difference between the two groups. Our results are compared with recent series and the causes of hearing loss associated with acoustic neuroma are discussed.

An investigation into the ability of soft drinks to adhere to enamel.

Loss of enamel due to dietary causes, either by acid erosion or the fermentation of dietary sugars, is well known. These processes will be affected by a number of factors, one of which is the ability of the food to adhere to the enamel. The aim of this study was to determine the thermodynamic work of adhesion of a number of soft drinks to enamel. The results indicated significant differences in the ability of various drinks to adhere to enamel in vivo. In addition to obtaining a ranking of the drinks under test, the likelihood of them being displaced by saliva was considered.

The prognostic value of individual histologic grading parameters in small lingual squamous cell carcinomas. The importance of the pattern of invasion.

BACKGROUND: The histologic grading of the deep invasive margin of oral squamous cell carcinoma recently has been shown to have prognostic value, but previous series have not been homogeneous enough to allow grading parameters to be assessed individually. METHODS: Forty-seven small lingual carcinomas limited to the lateral border of the tongue and treated by radiotherapy were graded histologically at their deep invasive front. Clinical and grading parameters were correlated by statistical tests performed by permutational techniques. RESULTS: Carcinoma recurred locally in 6 patients, and metastases developed in 19. Local recurrence correlated with Broders' grade (P = 0.0143), keratinization (P = 0.017) and pattern of invasion (P = 0.0195). Metastasis had a highly significant correlation with Broders' grade (P < 0.001), pattern of invasion (P < 0.001), and invasive front grading total score (P < 0.001). Seven of 8 carcinomas with diffuse infiltrating patterns metastasised, whereas only 4 of 25 with large islands or a broad infiltrating pattern metastasized. CONCLUSIONS: The usefulness of the deep invasive front grading system for small lingual carcinoma was demonstrated. The pattern of invasion was the component of the grading system that had the closest correlation with metastasis and recurrence in this type of carcinoma.

Sri Lankan cleft lip and palate study model analysis: clefts of the secondary palate.

The study models of a group of adult Sri Lankan patients with clefts of the secondary palate were investigated. Tooth-size and arch-dimension comparisons were made with a comparable control group. Significant differences were found between the cleft and control groups in tooth sizes, chord lengths, and arch widths. The cleft group dimensions were generally smaller than those of the control group. Overjets were larger in the cleft group.

The fate and survival of amalgam and preformed crown molar restorations placed in a specialist paediatric dental practice.

The fate of 1688 amalgam restorations and 716 preformed crowns placed in permanent and primary molars in a specialist paediatric dental practice over a 10-year period by one operator is reported. For primary molar amalgams, the replacement rate, true failure rate and 5-year survival estimates were, for Class 1 restorations, 16.1%, 3.9%, 73.3%, respectively, with an estimated median survival time greater than 8.5 years, and for Class 2 cavities 14.7%, 11.6%, 66.6%, with an estimated median survival time greater than 7.5 years. For permanent molar amalgams, the replacement rate, true failure rate and 5-year survival estimates were for Class 1 restorations 11.5%, 6.5%, 76.8%, respectively, with an estimated median survival time greater than 9.3 years, and for Class 2 restorations 9.8%, 8.0%, 82.2%, with a median survival time greater than 8.5 years. For all preformed crowns, the replacement rate, true failure rate and 5-year survival estimates were 2.8%, 1.9%, 92.0%, and the estimated median survival time greater than 7.64 years. No relationship was observed between the age of the patient and the age of replaced restorations. No significant difference was found between the survival rates of Class 1 and 2 amalgam restorations in primary or permanent molars, nor between first and second primary molars.