Amyotrophic Lateral Sclerosis, 2016: existing therapies and the ongoing search for neuroprotection

INTRODUCTION

Amyotrophic lateral sclerosis (ALS), one in a family of age-related neurodegenerative disorders, is marked by predominantly cryptogenic causes, partially elucidated pathophysiology, and elusive treatments. The challenges of ALS are illustrated by two decades of negative drug trials.

AREAS COVERED

In this article, we lay out the current understanding of disease genesis and physiology in relation to drug development in ALS, stressing important accomplishments and gaps in knowledge. We briefly consider clinical ALS, the ongoing search for biomarkers, and the latest in trial design, highlighting major recent and ongoing clinical trials; and we discuss, in a concluding section on future directions, the prion-protein hypothesis of neurodegeneration and what steps can be taken to end the drought that has characterized drug discovery in ALS.

EXPERT OPINION

Age-related neurodegenerative disorders are fast becoming major public health problems for the world's aging populations. Several agents offer promise in the near-term, but drug development is hampered by an interrelated cycle of obstacles surrounding etiological, physiological, and biomarkers discovery. It is time for the type of government-funded, public-supported offensive on neurodegenerative disease that has been effective in other fields.

Further development of biomarkers in amyotrophic lateral sclerosis

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is an idiopathic neurodegenerative disease usually fatal in less than three years. Even if standard guidelines are available to diagnose ALS, the mean diagnosis delay is more than one year. In this context, biomarker discovery is a priority. Research has to focus on new diagnostic tools, based on combined explorations.

AREAS COVERED

In this review, we specifically focus on biology and imaging markers. We detail the innovative field of 'omics' approach and imaging and explain their limits to be useful in routine practice. We describe the most relevant biomarkers and suggest some perspectives for biomarker research. Expert commentary: The successive failures of clinical trials in ALS underline the need for new strategy based on innovative tools to stratify patients and to evaluate their responses to treatment. Biomarker data may be useful to improve the designs of clinical trials. Biomarkers are also needed to better investigate disease pathophysiology, to identify new therapeutic targets, and to improve the performance of clinical assessments for diagnosis and prognosis in the clinical setting. A consensus on the best management of neuroimaging and 'omics' methods is necessary and a systematic independent validation of findings may add robustness to future studies.

Metabolomics in amyotrophic lateral sclerosis: how far can it take us?

Amyotrophic lateral sclerosis (ALS) is the most common adult-onset motor neuron disease. Alongside identification of aetiologies, development of biomarkers is a foremost research priority. Metabolomics is one promising approach that is being utilized in the search for diagnosis and prognosis markers. Our aim is to provide an overview of the principal research in metabolomics applied to ALS. References were identified using PubMed with the terms 'metabolomics' or 'metabolomic' and 'ALS' or 'amyotrophic lateral sclerosis' or 'MND' or 'motor neuron disorders'. To date, nine articles have reported metabolomics research in patients and a few additional studies examined disease physiology and drug effects in patients or models. Metabolomics contribute to a better understanding of ALS pathophysiology but, to date, no biomarker has been validated for diagnosis, principally due to the heterogeneity of the disease and the absence of applied standardized methodology for biomarker discovery. A consensus on best metabolomics methodology as well as systematic independent validation will be an important accomplishment on the path to identifying the long-awaited biomarkers for ALS and to improve clinical trial designs.

Smile aesthetics and malocclusion in UK teenage magazines assessed using the Index of Orthodontic Treatment Need (IOTN)

OBJECTIVE

There is a significant demand for orthodontic treatment within the UK from adolescent girls, a group known to be influenced by the media portrayal of body form and body image, which may extend to the presentation of malocclusions. This study examined the portrayal of malocclusion in a media type that targets teenage girls under 16 years of age.

MATERIALS AND METHODS

A representative selection of 1 month's magazines targeting this group were investigated, and the frequency and severity of malocclusions displayed were assessed. Two calibrated examiners viewed all the smiles (on two occasions) using a modification of Index of Orthodontic Treatment Need (IOTN) and assigned an Aesthetic Component Score to each smile.

RESULTS

It was found that the aesthetic score is low (less than 7) for the majority of models (92.8%) indicating no need or a borderline need for treatment. Only 7.2% of models exhibited a definite need for treatment.

CONCLUSION

It appears that the portrayal of malocclusion in teenage magazines does not reflect the general treatment need of the adolescent population.

Absence of the OPTN mutation in a patient with ALS and familial primary open angle glaucoma

The optineurin (OPTN) gene, known to be implicated in primary open-angle glaucoma (POAG), is the more recent genetic factor linked to ALS. We report the case of a 75year-old man who developed ALS and whose medical history was dominated by a familial POAG. The absence of OPTN gene mutation in a patient who suffered from two conditions linked to mutations of this gene does not support involvement of OPTN in ALS.

Screening for colorectal carcinoma

Colorectal carcinoma is the second most common cause of death in Canada. Because there is a precursor lesion (that is, the polyp), screening is critically important to prevent the disease through polyp removal-and failing that, to detect colorectal carcinoma at an early stage, when it can be cured. Several screening modalities are available, but colonoscopy is considered the best. People should avail themselves of such examinations, and physicians should encourage them to do so.

Respiratory onset in an ALS family with L144F SOD1 mutation

Familial amyotrophic lateral sclerosis (FALS) cases linked to SOD1 mutations may sometimes present with unusual clinical features such as pure lower motor neuron involvement or sensory signs. The authors describe a FALS pedigree with the L144F SOD1 mutation in which all cases had respiratory involvement as a first symptom. Although atypical clinical features are not rare in ALS families, this is the first pedigree with respiratory-onset in three affected members. This unusual presentation led to delayed diagnosis in the proband and highlights the fact that respiratory-onset can occur in familial ALS cases carrying SOD1 mutation.

APOE ε4 allele is associated with an increased risk of bulbar-onset amyotrophic lateral sclerosis in men

OBJECTIVE

  Several association studies have identified possible susceptibility factors for sporadic amyotrophic lateral sclerosis (SALS). Studies on the APOE gene provided conflicting results, especially about the effect on bulbar onset. We assessed the possible role of APOE gene in a large cohort of patients with ALS and matched controls.

METHODS

  The APOE alleles were determined in 1482 patients with SALS and 955 controls and analysed by univariate and multivariate statistics, taking into account gender, site-of-onset and age-at-onset.

RESULTS

  Patients with bulbar onset were more likely to be women [odds ratio (OR)=2.17; 95% CI: 1.74-2.72] and to be older (OR=3.47; 95% CI: 2.58-4.67). The ε4-carriers were more frequent in the bulbar-onset group than in the limb-onset group (OR=1.39 bulbar onset versus limb onset; 95% CI: 1.08-1.80) but this association was observed amongst men (OR=1.78; 95% CI: 1.25-2.53) and not women (OR=1.09; 95% CI: 0.75-1.59).

CONCLUSION

  Our study provides evidence for a contribution of the ε4 allele in the occurrence of bulbar-onset ALS amongst men. We propose that men are normally protected by androgens against bulbar onset and that the ε4 allele inhibits this protection, perhaps by interfering with the androgen pathway.

Prevalence of fatigue and depression in ALS patients and change over time

BACKGROUND

Amyotrophic lateral sclerosis (ALS) patients report both fatigue and depression. It is not clear how frequently each occurs, to what extent they occur together, how each relates to ALS disease status, or their stability over time.

OBJECTIVE

To assess frequency and persistence of fatigue and depression, and relationship to ALS disease status, for patients attending an ALS interdisciplinary centre for routine 3-month visits.

METHOD

Measures included the Fatigue Severity Scale, Patient Health Questionnaire-9. ALS Functional Rating Scale -- Revised and forced vital capacity, rate of disease progression, and bulbar/nonbulbar disease onset.

RESULTS

223 patients completed the ratings once; of these, 113 completed them twice, and 65 on three visits. At baseline, 44% (99/223) had clinically significant fatigue, including 34 patients who also had a depressive disorder; 7% (16/223) had major or minor depression only, and 48% (108/223) had neither condition. Fatigue was associated with greater ALS severity, but depression was not. Among the 113 patients seen 3 months later, 75% (33/44) who were fatigued at Time 1 remained fatigued, while 48% (10/21) remained depressed. New-onset fatigue was reported by 22% (25/113), and new-onset depression by 6% (7/113). For the 65 patients seen a third time, rates remained nearly the same.

CONCLUSION

Fatigue was more prevalent and persistent than depression, although 15% (34/223) of patients had both conditions. Fatigue but not depression was associated with ALS severity. The two conditions appear to be independent, although sometimes co-occurring, and both warrant consideration in evaluating patient functioning and treatment.

Successful treatment of extensive splanchnic arterial and portal vein thrombosis associated with ulcerative colitis

Venous and arterial thromboembolism is a significant cause of morbidity and mortality in patients with ulcerative colitis (UC). Arterial thrombosis of the splanchnic region is a rare event with a very high mortality rate. Furthermore, it represents a challenging complication since it tends to be overlooked and misinterpreted as a clinical exacerbation of UC. We present the case of a 62-year-old female with pancolonic UC complicated by an extensive arterial thrombosis involving the aorta, the celiac trunk, the hepatic, gastric and splenic arteries and the superior mesenteric artery. A thrombosis of the splenic vein extending into the proximal portal vein was also present. The patient was successfully treated by a combined interventional-radiological and surgical treatment. We discuss the rationale behind our management of this case and review the literature on splanchnic arterial thrombosis associated with UC.

Quantitative objective markers for upper and lower motor neuron dysfunction in ALS

OBJECTIVE

To investigate the value of objective biomarkers for upper (UMN) and lower (LMN) motor neuron involvement in ALS.

METHODS

We prospectively studied 64 patients with ALS and its subsets using clinical measures, proton MR spectroscopic imaging ((1)H MRSI), diffusion tensor imaging, transcranial magnetic stimulation, and the motor unit number estimation (MUNE) at baseline and every 3 months for 15 months and compared them with control subjects.

RESULTS

(1)H MRSI measures of the primary motor cortex N-acetyl-aspartate (NAA) concentration were markedly reduced in ALS (p = 0.009) and all UMN syndromes combined (ALS, familial ALS [fALS], and primary lateral sclerosis; p = 0.03) vs control values. Central motor conduction time to the tibialis anterior was prolonged in ALS (p < 0.0005) and combined UMN syndromes (p = 0.001). MUNE was lower in ALS (p < 0.0005) and all LMN syndromes combined (ALS, fALS, and progressive muscular atrophy; p = 0.001) vs controls. All objective markers correlated well with the ALS Functional Rating Scale-Revised, finger and foot tapping, and strength testing, suggesting these markers related to disease activity. Regarding changes over time, MUNE changed rapidly, whereas neuroimaging markers changed more slowly and did not significantly differ from baseline.

CONCLUSIONS

(1)H MR spectroscopic imaging measures of the primary motor cortex N-acetyl-aspartate (NAA) concentration and ratio of NAA to creatine, central motor conduction time to the tibialis anterior, and motor unit number estimation significantly differed between ALS, its subsets, and control subjects, suggesting they have potential to provide insight into the pathobiology of these disorders.

Development and evaluation of a self-administered version of the ALSFRS-R

We evaluated the reliability and sensitivity to change over time of a newly developed self-administered version of the ALS functional rating scale-revised (ALSFRS-R) in 60 consecutive patients from an ALS clinic. The self-administered ALSFRS-R showed excellent reliability (intraclass correlation = 0.93, 95% CI: 088 to 0.96) and similar sensitivity to change over time vs the standard evaluator-administered ALSFRS-R.

Randomized controlled phase II trial of glatiramer acetate in ALS

The authors conducted a randomized controlled trial to test the safety and immunology of glatiramer acetate in ALS. Twenty treated patients were randomly assigned to daily or biweekly injections. Ten control patients were selected from another trial and followed up concurrently. Injection reactions were the only common adverse event (p = 0.01). Treated patients showed enhanced lymphocyte proliferation (p = 0.02). The safety profile and immune effects support conducting larger trials of dose selection and efficacy.

The natural history of primary lateral sclerosis

OBJECTIVE

To define the syndrome of primary lateral sclerosis (PLS) and disorders that contain features of both ALS and PLS, to determine the time beyond which PLS is less likely to become ALS clinically, and to determine the outcome of people with PLS and those who develop lower motor neuron (LMN) signs.

METHODS

The authors reviewed the records of all 39 patients initially diagnosed with PLS in 1984 to 2004. Diagnostic subgroups were defined based on clinical features. The authors used Kaplan-Meier methods to estimate the time to diagnosis, linear regression analyses to assess function, and a Cox proportional hazard model to assess survival in subgroups.

RESULTS

Of the 39 patients, 29 had only upper motor neuron (UMN) signs on initial evaluation. Thirteen of the 29 were later classified as having UMN-dominant ALS (UMN-D) because they acquired evidence of denervation by EMG (3.17 years) or examination (3.67 years). Sixteen of the 29 patients, classified as clinically pure PLS, retained only UMN signs and a normal EMG (mean follow-up 8.7 years). Ten patients who met criteria for ALS at the initial visit were used as controls. The UMN-dominant ALS group had lower functional scores (p = 0.033) than the PLS group, and similar scores to those with ALS. Survival was longer in both the PLS group (p = 0.027) and the UMN-D group (p = 0.067) than the ALS group.

CONCLUSIONS

Clinically pure PLS can be defined by isolated UMN signs 4 years after symptom onset, and is a syndrome of slow progression with high levels of function. Prior to the fourth year, the diagnosis of PLS cannot be made with certainty because many patients develop LMN signs. UMN-dominant ALS, defined by predominantly UMN disease with minor LMN signs, has disability similar to ALS, but slower progression.

Novel genomic insertion-- deletion in MLH1: possible mechanistic role for non-homologous end-joining DNA repair

Hereditary non-polyposis colorectal cancer (HNPCC) is an inherited cancer syndrome caused by a defect in the mismatch repair pathway. The majority of HNPCC mutations have been detected in MLH1 and MSH2. Most reported mutations are substitutions, small insertions and deletions, but standard methods of mutation analysis do not detect large rearrangements. It is now established that large deletions, insertions and rearrangements account for a significant proportion of MLH1 and MSH2 mutations. We report an unusual rearrangement resulting in the deletion of exons 6, 7 and 8 of MLH1, with the retention of part of intron 6 and insertions of two nucleotides each flanking the retained sequence. The 349-bp-retained sequence is made up of two closely spaced Alu sequences. The mutation was initially detected by protein truncation test and cDNA sequencing. Multiplex ligation-dependent probe amplification confirmed the deletion of three exons. PCR and sequencing were used to characterize the breakpoint. Despite the high density of Alu elements in MLH1, there is no homology at the deletion breakpoints or insertion junctions in this case to suggest that homologous recombination has occurred. We propose a mechanism involving non-homologous end joining to explain the occurrence of this complex deletion.

Injuries sustained by colorectal surgeons performing colonoscopy

BACKGROUND

Repetitive tasks in the workplace are one cause of injury. This study aimed to identify injuries specific to physicians routinely performing colonoscopy, and to identify prevention strategies.

METHODS

A survey was sent to all 2,173 worldwide members of the American Society for Colon and Rectal Surgery to investigate injuries or disabilities that resulted from performing colonoscopy and the methods used to prevent and alleviate symptoms related to the procedure.

RESULTS

The response rate was 28%. Of the respondents, 96% performed colonoscopy. At least one injury or pain believed to result from performing colonoscopy was reported by 39% of the respondents. The most frequently reported injuries were to hands and fingers (n = 257), neck (n = 65), and back (n = 52). The methods adopted to alleviate injury included changing the height of the stretcher or video monitor, changing from a standing to a sitting position, minimizing torque on the colonoscope, having an assistant perform the torque maneuver, and resting or taking time off from colonoscopy. Two respondents also created devices to make the instrument more ergonomic.

CONCLUSION

The number of colorectal surgeons encountering injury from colonoscopy highlights the need for preventive strategies. The study results suggest that it may be necessary to improve the design of colonoscopes to make them more ergonomic. Appropriate positioning of the endoscopist, patient, and monitors may diminish some of the injuries encountered.

Disruption of an exon splicing enhancer in exon 3 of MLH1 is the cause of HNPCC in a Quebec family

BACKGROUND

A 3 bp deletion located at the 5' end of exon 3 of MLH1, resulting in deletion of exon 3 from RNA, was recently identified.

HYPOTHESIS

That this mutation disrupts an exon splicing enhancer (ESE) because it occurs in a purine-rich sequence previously identified as an ESE in other genes, and ESEs are often found in exons with splice signals that deviate from the consensus signals, as does the 3' splice signal in exon 3 of MLH1.

DESIGN

The 3 bp deletion and several other mutations were created by polymerase chain reaction mutagenesis and tested using an in vitro splicing assay. Both mutant and wild type exon 3 sequences were cloned into an exon trapping vector and transiently expressed in Cos-1 cells.

RESULTS

Analysis of the RNA indicates that the 3 bp deletion c.213_215delAGA (gi:28559089, NM_000249.2), a silent mutation c.216T-->C, a missense mutation c.214G-->C, and a nonsense mutation c.214G-->T all cause varying degrees of exon skipping, suggesting the presence of an ESE at the 5' end of exon 3. These mutations are situated in a GAAGAT sequence 3 bp downstream from the start of exon 3.

CONCLUSIONS

The results of the splicing assay suggest that inclusion of exon 3 in the mRNA is ESE dependent. The exon 3 ESE is not recognised by all available motif scoring matrices, highlighting the importance of RNA analysis in the detection of ESE disrupting mutations.

The ALSFRSr predicts survival time in an ALS clinic population

OBJECTIVE

To determine whether the Amyotrophic Lateral Sclerosis Functional Rating Scale-revised (ALSFRSr), a predictor of survival time in ALS clinical trials, predicts survival time in an ALS clinic population.

METHODS

The authors prospectively evaluated 267 consecutive patients with ALS at first visit to an ALS clinic using the ALSFRSr and pulmonary function testing. The association of ALSFRSr score at baseline with death or tracheostomy in ALS was examined using Cox proportional hazards models, adjusting for age at baseline, sex, and symptom duration.

RESULTS

Of 267 patients with ALS, 103 (39%) reached the endpoint, defined as either death (79 patients) or tracheostomy (24 patients), during a mean follow-up of 1.0 +/- 0.7 years. Among the 103 patients who reached the endpoint during follow-up, 77 (75%) had a baseline ALSFRSr score of less than 38 (the median baseline score of all patients), compared to 53 of 164 (32%) who remained alive without tracheostomy. Patients with a total ALSFRSr score below the median had a 4.4-fold increased risk of death or tracheostomy compared to those who scored above the median (HR: 4.38, 95% CI: 2.79 to 6.86, p < 0.001). Both the total ALSFRSr score at baseline (HR: 0.94, 95% CI: 0.91 to 0.98, p < 0.001) and forced vital capacity at baseline (HR: 0.99, 95% CI: 0.98 to 1.00, p = 0.02) were associated with death or tracheostomy when included in the same Cox model.

CONCLUSIONS

In an ALS clinic population, the total Amyotrophic Lateral Sclerosis Functional Rating Scale-revised score at baseline is a strong predictor of death or tracheostomy independently of forced vital capacity and after adjustment for age at baseline, sex, and symptom duration.

Undergraduate orthodontic teaching in the new millennium--the Newcastle model

This paper identifies the main factors which have influenced the nature of the undergraduate orthodontic curriculum presently taught at Newcastle University. It also outlines the philosophy that underpins the teaching, states the professional aims of the tutors and spells out the clinical objectives set for the students.

Long-term outcome of rubber band ligation for symptomatic primary and recurrent internal hemorrhoids

PURPOSE

Rubber band ligation therapy for symptomatic hemorrhoidal disease has been used for many years and is a well-accepted treatment modality, but information on long-term outcome is limited. Our goals were to determine safety and long-term efficacy of this treatment.

METHODS

A retrospective chart review of patients undergoing rubber band ligatures for symptomatic internal hemorrhoids in a single practice was conducted. Information on presenting symptoms, number of bands applied, response to therapy, complications encountered, length of follow-up, interval to recurrent symptoms when applicable, and subsequent therapy were documented. Supplemental information was obtained from telephone follow-up. Outcome was categorized as success or failure, in which success was defined as: permanent relief of symptoms for follow-up period; marked improvement in symptomatology with rare manifestation of bleeding (< or = 1/month); symptom relief for a limited period of time (> or = 100 days), and failure was defined as: modest improvement (decreased but not relief of symptoms); or no improvement in symptoms.

RESULTS

A total of 805 patients underwent 2,114 rubber band ligatures. Most common presenting symptoms were bleeding in 731 patients (90.8 percent) and prolapsing in 382 patients (47.5 percent). The median number of bands placed was two (range, 1-17). The median time between bandings was 4.7 (range, 1.1-35.6) weeks. Median follow-up time was 1,204 (range, 14-9,571) days. Excluding 104 patients lost to follow-up (never returned after initial treatment), success was obtained in 70.5 percent (494/701) and failure in 29.5 percent (207/701) of patients. Success rates were similar for all degrees of hemorrhoids. Hemorrhoidal disease requiring the placement of four or more bands was associated with a trend in higher failure rates and greater need for subsequent hemorrhoidectomy. Complications per treatment series included bleeding (2.8 percent), thrombosed external hemorrhoids (1.5 percent), and bacteremia (0.09 percent). Higher bleeding rates were encountered with the use of acetylsalicylic acid/nonsteroidal anti-inflammatory drugs and warfarin. Time to recurrence was less with subsequent treatment courses. Treatment of recurrent symptoms with rubber band ligation resulted in success rates of 73.6, 61.4, and 65 percent for first, second, and third recurrences respectively. This resulted in a cumulative success rate of 80.2 percent for this method of treatment.

CONCLUSIONS

Rubber band ligatures are safe and effective therapy for symptomatic internal hemorrhoids. It can be used to treat all degrees of hemorrhoids with similar effectiveness. The likelihood of success is lower if more than four bands are needed to eliminate symptoms. The use of acetylsalicylic acid/nonsteroidal anti-inflammatory drugs and warfarin is associated with higher bleeding rates. Rubber band ligatures for recurrence of symptoms is effective; however, time to recurrence is less with subsequent treatments.

Placebo-controlled phase I/II studies of minocycline in amyotrophic lateral sclerosis

Two double-blind, randomized, placebo-controlled feasibility trials of minocycline in ALS were conducted. In Trial 1, 19 subjects received 200 mg/day or placebo for 6 months; there were no significant differences in adverse events (AE). In Trial 2, 23 subjects received up to 400 mg/day in an 8-month crossover trial. The mean tolerated dose was 387 mg/day, there was a trend toward more gastrointestinal AE (p = 0.057), and blood urea nitrogen and liver enzymes became elevated (p < 0.05). Using these data, the authors have designed and launched a phase III trial.

Do distal adenomas mandate total colonoscopy?

BACKGROUND

Distal adenomas have been considered markers of proximal neoplasms. It also has been suggested that patients with small, distal adenomas do not require proximal examination of the colon. This study was conducted to determine the validity of the latter recommendation.

METHODS

From a total of 5,132 colonoscopies performed between 1976 and 1999, all patients from whom adenomas were removed were included. Those with previous colon resections or incomplete cecal intubation were excluded. Proximal adenomas were defined as those proximal to the sigmoid colon. Adenomas were considered advanced if they were 1 cm or larger, contained any villous component, or demonstrated severe dysplasia.

RESULTS

The study included 226 patients. Overall, 98 patients had distal adenomas, and there was a synchronous proximal adenomas rate of 23.4%. Patients with single, small, rectosigmoid, tubular adenomas had proximal adenomas at a rate of 28.8%, and 9.6% were advanced adenomas. Patients with advanced distal adenomas had synchronous proximal adenomas at a rate of 18.9%, and 10.8% of these were advanced adenomas. According to multiple logistic regression, the strongest predictor of proximal neoplasia was the absence of distal polyps.

CONCLUSION

These data confirm the necessity for total colonoscopy in all patients with distal adenomas regardless of size. In addition, the high proportion of proximal neoplasia without distal markers suggests that full colonoscopy may be warranted as a screening tool in all patients.

An ex vivo investigation to compare orthodontic bonding using a 4-META-based adhesive or a composite adhesive to acid-etched and sandblasted enamel

OBJECTIVE

This study investigates the shear-peel orthodontic bond strengths of brackets bonded with an unfilled acrylic resin containing 4-META (MCP Bond or a no-mix composite adhesive (Right On) to acid-etched or sandblasted enamel.

DESIGN

Ex vivo.

MATERIALS AND METHODS

Eighty human pre-molar teeth were separated into four equal groups, according to the adhesive used and method of enamel pre-treatment. Group I-Right On with enamel etched using phosphoric acid for 30 seconds. Group II-Right On with enamel sandblasted using 50- microm alumina particles at 80 psi for 3 seconds. Group III-MCP Bond with enamel etched using phosphoric acid for 30 seconds. Group IV-MCP Bond with enamel sandblasted using 50- microm alumina particles at 80 psi for 3 seconds. Subsequently, the specimens were stored in distilled water for 24 hours prior to bond strength testing using an Instron universal testing machine. Each debonded tooth was scored using the adhesive remnant index (ARI) to determine the site of bond failure.

RESULTS

The mean bond strength (1 SD) were Group I: 10.7 (2.7) MPa, Group II: 5.3 (1.3) MPa, Group III: 15.9 (3.4) MPa, Group IV: 15.0 (2.2) MPa. Statistical analysis using one-way analysis of variance and Tukey test found no statistical difference between Group III and Group IV (P > 0.05), but the other groups were statistically different from each other (P < 0.05). The data were found to fit the Weibull distribution and Weibull analysis showed stress required for a 5 per cent probability of failure was: Group I: 5.77 MPa; Group II: 3.32 MPa; Group III: 10.31 MPa; Group IV: 10.58 MPa. Chi-square test showed a statistically significant difference existed between the ARI scores (P < 0.001), principally through less adhesive remnants being observed on the sandblasted specimens.

CONCLUSION

The adhesive containing 4-META achieved significantly higher bond strengths than the composite adhesive, particularly in the case of sandblasted enamel.

Dental erosion -- changing prevalence? A review of British National childrens' surveys

OBJECTIVES

To investigate the change in the prevalence of dental erosion, over time, by a review of the data from the published national dental surveys of young people in the UK. A subsidiary objective was to investigate the relationship between erosion and possible associated risk factors.

DESIGN

The review was based on cross-sectional prevalence studies incorporating a clinical dental examination and structured interviews.

SAMPLE

The data were collated from the 1993 UK childrens' dental health survey and the dental report of the two National Diet and Nutrition Surveys (NDNS) of children aged 1(1/2)-4(1/2) in 1992/3 and 4-18 years in 1996/7. The criteria used for data collection were comparable between the three different studies.

RESULTS

Comparing the data from the different studies, the prevalence of erosion was seen to increase from the time of the childrens' dental health survey in 1993 and the NDNS study of 4-18-year-olds in 1996/7. There was a trend towards a higher prevalence of erosion in children aged between 3(1/2) and 4(1/2) and in those who consumed carbonated drinks on most days compared with toddlers consuming these drinks less often. Drinks overnight were associated with an increased prevalence of erosion. More 4-6-year-olds with reported symptoms of gastro-oesophageal reflux had erosion compared with symptom-free children. On multivariate analysis, the strongest independent association with erosion was geography, with children living in the North having twice the odds of having erosion compared with those in London and the South-east.

CONCLUSIONS

Comparing prevalence data from cross-sectional national studies indicates that dental erosion increases between different age cohorts of young people over time. Dietary associations with erosion are present but weak. Similarly, there is an association apparent between erosion, symptoms of gastro-oesophageal reflux and socio-demographic variables such as region of domicile, social class, and receipt of social benefits.

The founder mutation MSH2*1906G-->C is an important cause of hereditary nonpolyposis colorectal cancer in the Ashkenazi Jewish population

Hereditary nonpolyposis colorectal cancer (HNPCC) is caused by mutations in the mismatch-repair genes. We report here the identification and characterization of a founder mutation in MSH2 in the Ashkenazi Jewish population. We identified a nucleotide substitution, MSH2*1906G-->C, which results in a substitution of proline for alanine at codon 636 in the MSH2 protein. This allele was identified in 15 unrelated Ashkenazi Jewish families with HNPCC, most of which meet the Amsterdam criteria. Genotype analysis of 18 polymorphic loci within and flanking MSH2 suggested a single origin for the mutation. All colorectal cancers tested showed microsatellite instability and absence of MSH2 protein, by immunohistochemical analysis. In an analysis of a population-based incident series of 686 Ashkenazi Jews from Israel who have colorectal cancer, we identified 3 (0.44%) mutation carriers. Persons with a family history of colorectal or endometrial cancer were more likely to carry the mutation than were those without such a family history (P=.042), and those with colorectal cancer who carried the mutation were, on average, younger than affected individuals who did not carry it (P=.033). The mutation was not detected in either 566 unaffected Ashkenazi Jews from Israel or 1,022 control individuals from New York. In hospital-based series, the 1906C allele was identified in 5/463 Ashkenazi Jews with colorectal cancer, in 2/197 with endometrial cancer, and in 0/83 with ovarian cancer. When families identified by family history and in case series are included, 25 apparently unrelated Ashkenazi Jewish families have been found to harbor this mutation. Although this pathogenic mutation is not frequent in the Ashkenazi Jewish population (accounting for 2%-3% of colorectal cancer in those whose age at diagnosis is <60 years), it is highly penetrant and accounts for approximately one-third of HNPCC in Ashkenazi Jewish families that fulfill the Amsterdam criteria.

The changed histologic paradigm of colorectal polyps

BACKGROUND

Previous literature has recorded the preponderance of hyperplastic over neoplastic polyps. This study evaluated the histopathologic characteristics of colonic polyps, excised during colonoscopic polypectomy, and further determined their relationship to age, location, and gender.

METHODS

Of 5132 colonoscopies reviewed between 1976 and 1999, 757 were performed on 582 patients who had polyp removal. Patients with previous colon resection or incomplete cecal intubation were excluded.

RESULTS

The mean age was 67 +/- 11 years for men and 66 +/- 11 years for women. Of the 1050 lesions histologically analyzed, 871 (83.0%) were neoplastic, 129 (12.3%) were hyperplastic, and 50 (4.8%) were miscellaneous lesions (29 inflammatory polyps, 14 lipomas, 2 leiomyomas, 1 juvenile polyp, and 4 no pathology identified). Hyperplastic polyps were always less than 1 cm (with one exception) and were located predominantly in the left colon, the majority residing in the sigmoid colon. Peak prevalence of hyperplastic polyps occurred in the 50-70 years old age group. Of the neoplastic polyps, 566 (65.0%) were tubular, 225 (25.8%) villotubular, 63 (7.2%) villous adenomas, 4 (0.5%) mixed adenomatous hyperplastic polyps, and 12 (1.4%) invasive carcinomas. The peak prevalence of neoplastic polyps occurred in the same age group as did hyperplastic polyps. Even though adenomatous polyps outnumbered hyperplastic polyps throughout the colon and within each age group, a greater percentage of hyperplastic polyps were found distally and in younger patients compared to location and age groups for neoplastic polyps.

CONCLUSION

Adenomatous polyps outnumber hyperplastic polyps 7:1, even in the distal colon. Even small polyps seen during colonoscopy should be removed and subjected to histologic analysis because of the advisability of follow-up examinations of patients with neoplastic polyps. The increase in the incidence of neoplastic polyps beginning at the age of 50 years supports the need for colonoscopy in these individuals.

The value of specialization--is there an outcome difference in the management of fistulas complicating diverticulitis

PURPOSE

The value of specialization has frequently been challenged by many health care institutions and providers. This review was conducted to determine whether there were any outcome differences in the management of fistulas complicating diverticulitis.

METHODS

We conducted an historical cohort study using hospital charts of all cases of fistulas complicating diverticulitis that were operated on in four university-affiliated hospitals between 1975 and 1995. There were 122 patients, with 37 under the care of fully trained colorectal surgeons and 85 under the care of general surgeons.

RESULTS

There were no significant differences in patient demographics, preoperative comorbidities, or the number of preoperative diagnostic investigations between the two groups. The colorectal surgeons performed more intraoperative ureteral stenting (Colorectal Surgery 55.5 percent vs. General Surgery 24.4 percent, P = 0.001). The general surgeons performed more initial diverting Hartmann's and colostomy procedures (Colorectal Surgery 5.4 percent vs. General Surgery 27 percent, P = 0.013). The patients in the General Surgery group had longer preoperative lengths of stay (median Colorectal Surgery 3 (range, 1-28) days vs. General Surgery 8 (range, 0-29) days; P < 0.001), longer postoperative lengths of stay (median Colorectal Surgery 11 (range, 5-40) days vs. General Surgery 14 (range, 2-80) days; P = 0.001), and longer total lengths of stay (median Colorectal Surgery 14 (range, 6-62) days vs. General Surgery 24 (range, 6-100) days; P < 0.001). The patients in the General Surgery group experienced a higher rate of wound infections (Colorectal Surgery 5.4 percent vs. General Surgery 12.9 percent), and a larger proportion of them experienced complications (Colorectal Surgery 27 percent vs. General Surgery 41.2 percent).

CONCLUSIONS

We conclude that specialization in colon and rectal surgery contributed to an improved outcome, with a lower rate of diverting procedures, a shorter hospital stay, and a lower rate of complications.

Novel operative management of primary mesenteric volvulus

Mesenteric volvulus is a potentially life-threatening condition. Little information is available for the recommended treatment of viable bowel and virtually no information is available for the suggested elective treatment of a mesenteric volvulus. This communication details a series of enteropexies that were successful in the management of this disorder.

Neuroleptic malignant syndrome in advanced Parkinson's disease

Neuroleptic malignant syndrome is a serious complication of levodopa withdrawal in patients with Parkinson's disease. We report a patient with advanced parkinsonism who developed neuroleptic malignant syndrome in the setting of inadequate levodopa intake. His symptoms improved with levodopa replacement, but dramatically worsened when enteral feeding was begun due to interference with intestinal absorption of levodopa.

Early electrodiagnostic findings in Guillain-Barré syndrome

CONTEXT

Guillain-Barré syndrome (GBS) is the foremost cause of acute, generalized, peripheral neuropathic weakness. Although nerve conduction studies are a diagnostic aid, the characteristic electrical changes may not evolve for several weeks. Early diagnosis of GBS is important, however, because early treatment has been shown to improve outcome.

OBJECTIVES

To describe the electrodiagnostic abnormalities detectable in the first week of GBS, to determine if there are early patterns suggestive of GBS, and to identify the percentage of patients whose condition can be diagnosed with reasonable certainty in the first week.

DESIGN AND SETTING

We retrospectively reviewed the medical records of all patients admitted to the Cleveland Clinic Foundation, Cleveland, Ohio, having the discharge diagnosis GBS during the past 16 years. Patients who underwent nerve conduction studies within 7 days of muscle weakness were selected for this study.

RESULTS

The H reflex was absent in 30 (97%) of 31 patients. Nineteen patients (61%) had low-amplitude or absent sensory nerve action potential (SNAP) in the upper extremity. Fifteen patients (48%) overall, including 21 (67%) of the 31 patients, including 14 (67%) of the 21 patients younger than 60 years, had an abnormal upper extremity SNAP combined with a normal sural SNAP. Other findings included an abnormal F wave (25 patients [84%]), reduced compound muscle action potential amplitude (22 patients [71%]), prolonged distal latency (20 patients [65%]), temporal dispersion (18 patients [58%]), slowed motor conduction velocity (16 patients [52%]), and motor conduction block (4 patients [13%]). Definite diagnosis was possible in 17 patients (55%), but not commonly until the fifth day.

CONCLUSIONS

The H reflex is the most sensitive test for early GBS. Upper extremity SNAPs are also frequently abnormal in early GBS. Absent H response, abnormal F wave, and abnormal upper extremity SNAP combined with a normal sural SNAP are characteristic of early GBS. If multiple nerves are tested, definite diagnosis is possible in half the patients, but not until the fifth day after the onset of symptoms.

The dramatic presentation of colonic lipomata: report of two cases and review of the literature

Colonic lipoma with a dramatic presentation requiring urgent operation is a rare occurrence. We report two such cases in conjunction with a review of the literature on colonic lipomata. Clinicopathologic features of two patients who required urgent resection were studied. The preoperative diagnosis of colonic lipoma was suggested on imaging study in one case. A MEDLINE search was conducted with a special goal of revealing cases with a dramatic presentation. One patient presented with rectal bleeding and intussusception related to a partially infarcted 4.5-cm submucosal lipoma of the lower descending colon. The second patient presented with intestinal obstruction related to a near-totally infarcted 6-cm submucosal lipoma at the splenic flexure. In both cases a florid reactive vascular and fibro-/myofibroblastic proliferation and associated hyperplastic mucosal pattern were present at the base and edge of the lipoma. Among 275 previously reported cases of colonic lipoma 28 patients had a dramatic presentation with pain and/or rectal bleeding being the most significant prodromal symptom. In this subset the lipomas tended to be larger, frequently had associated marked necrosis/ulceration, and were less likely to be located in the ascending colon/cecum. Whereas colonic lipomas are relatively common occasional cases present dramatically with massive bleeding, intussusception, or even perforation for which emergency operation is required. Such lipomas usually reveal marked ischemic changes.

Glutaraldehyde-induced colitis

OBJECTIVE

To describe the etiology and clinical course of acute colitis occurring after flexible endoscopy.

DESIGN

Chart review.

SETTING

A university teaching hospital.

PATIENTS

Eight patients who sought assessment of potential colonic disease.

INTERVENTION

Colonoscopy in 5 patients and flexible sigmoidoscopy in 3 patients. The indication for endoscopy was screening in 5 patients, cancer surveillance in 2 patients and preoperative evaluation of colon carcinoma in 1 patient.

OUTCOME MEASURES

The relation of presenting symptoms to glutaraldehyde exposure, the response to therapy and the need for further therapy.

RESULTS

All patients had abdominal pain, mucus diarrhea and rectal bleeding within 48 hours after endoscopy. Most patients reported that the symptoms started within 12 hours of the procedure. All patients were confirmed by sigmoidoscopy to have colitis within 72 hours of the first endoscopic procedure. One patient required hospitalization. In the first 7 patients several stool cultures were negative for Clostridium difficile using the cytotoxin assay by the cell culture method. Four patients had negative cultures for Yersinia, Salmonella and Shigella spp. Three patients were treated with metronidazole initially. Two patients underwent endoscopic biopsy and examination of the biopsy specimen showed fibrinoleukocytic exudate and ischemic type injury. One patient underwent the scheduled sigmoid resection within 48 hours of endoscopy for a Dukes' stage B adenocarcinoma. Concomitant acute ischemic colitis limited to the mucosa and submucosa was noted in the resected specimen. Symptoms resolved in all patients and follow-up endoscopy revealed normal mucosa.

CONCLUSION

The entity of glutaraldehyde-induced colitis should be recognized and special attention should be given during instrument cleansing to minimize the risk of its development.

Role of molecular diagnostic testing in familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer families

PURPOSE

Genetic tests are available for familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer. The goal of this review was to develop an algorithm for application of molecular diagnostic techniques to the management of hereditary colorectal carcinoma and to familiarize the clinician with the vocabulary of molecular genetic testing for hereditary colorectal carcinoma.

METHODS

Studies examining the clinical use of genetic testing for hereditary colorectal carcinoma syndromes are evaluated. Recent advances in molecular genetic technology are reviewed, and clinical management as practiced here and elsewhere is outlined.

RESULTS

This review is a guide to the most reliable molecular diagnostic techniques. Three key questions are answered: who, when, and how to test.

CONCLUSIONS

When integrated with existing testing protocols for colorectal carcinoma and when applied with appropriate caveats, particularly regarding interpretation of negative results, genetic testing can result in improved management of patients and families.

Anorectal anatomy and physiology

Knowledge of anorectal anatomy is essential for understanding the normal function of the anorectum. Its physiology is more complex, however. The maintenance of continence depends on several factors, and today clinicians have a better understanding of the usual sequence of events that leads to defecation. The extensive number of investigative techniques that have evolved have permitted better understanding of the disorders of the anal sphincters, rectum, and pelvic floor.

An ex vivo study to investigate bond strengths of different tooth types

This study aimed to identify the presence and pattern of differences in ex vivo shear bond strength between tooth types when bonding orthodontic brackets using Right-On, and took the form of a prospective laboratory study of bond strength on different tooth types, at the Newcastle University Dental School Materials Science Laboratory, 1997-1999. Ex vivo bond strength testing was undertaken using the technique described by Fox et al. (BJO 18, 125-130, 1991) on a total of 120 extracted incisor, canine, and premolar teeth of each dental arch. Analysis was by one-way ANOVA with Tukey's pairwise comparisons, and by Weibull Analysis. Shear stress to failure (measured in MPa) was recorded on Instron 5567 universal testing machine. Significant differences in mean bond strength existed between different tooth-type series. Canine (upper 12.3, lower 12.1) and premolar (upper 11.9, lower 10.9) teeth exhibited higher strengths than incisors (upper 6.9, lower 9.0). The results of this study confirm that ex vivo bond strength is not uniform across all teeth.

Genetic counseling and interpretation of genetic tests in familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer

PURPOSE

Genetic counseling and interpreting genetic test results can be complex. Moreover, without knowing the limitations of the methods used and the lifetime probability of developing cancer in individuals who carry a gene that predisposes to cancer, misinterpretation may lead to false assurance. The purpose of this review is to discuss how genetic counseling will benefit patients and their family, the genetic tests available for hereditary colorectal cancer syndromes, and the interpretation of results.

METHODS

Current literature was reviewed and our clinical and research experiences were incorporated.

RESULTS

This review serves as a guide to enable various health care providers to better counsel patients in their quest for advice on prevention, early detection, and surveillance for colorectal cancer. Notable topics of discussion are who should undergo genetic counseling and consider testing and how the interpretation of test results can be misleading; for example, understanding the difference between a no mutation detected vs. a negative test result.

CONCLUSIONS

Genetic counseling is of paramount importance for patients to fully understand the limitations of genetic testing and will aid in the management of patients who are susceptible to colorectal cancer.

An analysis of the skeletal relationships in a group of young people with hypodontia

The objective of this investigation was to examine the dentofacial features of a group of patients with hypodontia, in particular assessing whether cephalometric analysis confirmed the clinical assumption of a reduced lower face height, and to determine the relationship of these facial features with different numbers of missing teeth. It took the form of a cephalometric study, undertaken in a dedicated Dental Hospital clinic for patients with hypodontia. The study group comprised 59 patients seen on the Hypodontia Clinic: 32 females, 27 males, mean age 13.1+/-3.1 years (range 6-23 years). The average number of missing teeth was 7 (SD 5), ranging from 1 to 21. The mean SNA, SNB, and MMA angles were within normal limits, but there was a statistically significant reduction in the MMA when more than one tooth type was missing (P = 0.007) and the ANB angle decreased as the number of missing tooth types increased (P = 0.034). The mean values for the whole sample were within the normal range and did not demonstrate any feature specific to the group, but patients with more severe hypodontia showed tendencies to a Class III skeletal relationship and a reduced maxillary-mandibular planes angle.

An ex vivo assessment of resin-modified glass ionomer bonding systems in relation to ceramic bracket debond

This ex vivo study assessed three new resin-modified glass ionomer cements (Fuji ORTHO LC, Vitremer, and Dyract-Cem) in relation to ceramic bracket removal. It was hypothesized that the use of these cements would facilitate bracket removal and eliminate debond complications Eighty extracted premolar teeth were divided into four groups of 20 teeth and bonded with Intrigue brackets using each of the resin-modified cements (groups 1, 2, and 3), the control group 4 was bonded with Concise chemically-cured adhesive. The teeth were debonded by applying a shear load using an Instron universal testing machine. The mean force to debond was calculated for each group and each tooth was examined under the stereomicroscope to record the site of bond failure and the Adhesive Remnant Index (ARI). The results showed that the resin-modified cements were very effective at eliminating ceramic bracket debond problems. Bracket fracture was eliminated compared with a 40 per cent fracture rate with the control and the ARI scores were all reduced. The elimination of debond problems appears to be related to the significantly reduced (P < 0.001 using ANOVA and Tukey tests) mean and maximal debond forces compared with the control.

Small-bowel obstruction secondary to malignant disease: an 11-year audit

OBJECTIVE

To determine the efficacy and long-term prognosis for operative versus nonoperative treatment of small-bowel obstruction (SBO) secondary to malignant disease.

DESIGN

A chart review.

SETTING

A university-affiliated teaching hospital.

PATIENTS

The medical records of all patients with malignant disease as the established etiology of their obstruction who presented to the Sir Mortimer B. Davis-Jewish General Hospital, Montreal, between 1986 and 1996 were reviewed. There were 32 patients accounting for 74 admissions.

INTERVENTIONS

Selective nonoperative management and exploratory laparotomy, immediate or delayed.

MAIN OUTCOME MEASURES

The value of nonoperative management and need for operation.

RESULTS

Colorectal and ovarian neoplasms were the principal primary malignant diseases that led to SBO. The median time between diagnosis of the malignant disease and SBO was 1.1 years. At their initial presentation, 80% of patients were treated by operation, but 47% of these patients had an initial trial of nonoperative treatment. Reobstruction occurred in 57% of patients who were operated on compared with 72% of patients who were not. The median time to reobstruction was 17 months for patients who underwent operation compared with 2.5 months for patients who did not. Also, 71% of patients were alive and symptom free 30 days after discharge from operative treatment compared with 52% after nonoperative treatment. Postoperative morbidity was 67%. Mortality was 13%, and 94% of patients eventually died from complications of their primary disease.

CONCLUSIONS

SBO secondary to malignant disease usually indicates a grim prognosis. Operative treatment has better outcome than nonoperative management in terms of symptom free interval and reobstruction rates. However, it is marked by high postoperative morbidity. We recommend that, after short trial of nasogastric decompression, patients with obstruction secondary to malignant disease be operated on if clinical factors indicate they they will survive the operation.

Natural history of patients with adhesive small bowel obstruction

BACKGROUND

Small bowel obstruction (SBO) is a major cause of morbidity and financial expenditure. The goals of this study were to determine factors predisposing to adhesive SBO, to note the long-term prognosis and recurrence rates for operative and non-operative treatment, to elicit the complication rate of operations and to highlight factors predictive of recurrence.

METHODS

The medical records of all patients admitted to one hospital between 1986 and 1996 with the diagnosis of SBO were reviewed retrospectively. This included 410 patients accounting for 675 admissions.

RESULTS

The frequency of previous operation by procedure type was colorectal surgery (24 per cent), followed by gynaecological surgery (22 per cent), herniorrhaphy (15 per cent) and appendicectomy (14 per cent). A history of colorectal surgery (odds 2.7) and vertical incisions (odds 2.5) tended to predispose to multiple matted adhesions rather than an obstructive band. At initial admission 36 per cent of patients were treated by means of operation. As the number of admissions increased, the recurrence rate increased while the time interval between admissions decreased. Patients with an adhesive band had a 25 per cent readmission rate, compared with a 49 per cent rate for patients with matted adhesions (P<0.004). At the initial admission 36 per cent of patients were treated surgically. Patients treated without operation had a 34 per cent readmission rate, compared with 32 per cent for those treated surgically (P not significant), a shorter time to readmission (median 0.7 versus 2.0 years; P<0.05), no difference in reoperation rate (14 versus 11 per cent; P not significant) and fewer inpatient days over all admissions (4 versus 12 days; P<0.0001).

CONCLUSION

The likelihood of reobstruction increases and the time to reobstruction decreases with increasing number of previous episodes of obstruction. Patients with matted adhesions have a greater recurrence rate than those with band adhesions. Non-operative treatment for adhesions in stable patients results in a shorter hospital stay and similar recurrence and reoperation rates, but a reduced interval to reobstruction when compared with operative treatment.

The use of a cyanoacrylate adhesive for bonding orthodontic brackets: an ex-vivo study

The purpose of this study was to evaluate the performance of a cyanoacrylate orthodontic adhesive with regard to tensile bond strength and bond failure location in comparison with a conventional no-mix orthodontic composite adhesive using stainless steel and ceramic brackets. One-hundred-and-twenty caries-free extracted premolar teeth were used in this study. There were 30 specimens for each tooth, adhesive, and bracket combination, and of these half were tested at 24 hours and half at 3 months. Hence, there were 15 samples in each test group. Bond strengths were assessed using an Instron Universal Testing Machine after storage for 24 hours and for 3 months at 37 degrees C in distilled water. Analysis of variance showed the mean bond strength of specimens bonded with cyanoacrylate was significantly lower than for those bonded with Right-on (P < 0.001). Weibull analysis showed that at a given stress the probability of failure significantly increased after 3 months for brackets bonded with cyanoacrylate. A Chi-square test of the ARI scores revealed no significant difference among the groups tested. This study showed that cyanoacrylate adhesives are unsuitable for use as a bonding agent in routine orthodontic practice.

Comparison of erosion of dental enamel by four drinks using an intra-oral applicance

There are several causes of erosion - acidic foods and drinks have been implicated and reducing their erosive potential would seem an important area of research. Calcium-citrate-malate (CCM) appeared to have potentially useful properties as an anti-erosion additive. The study aims were to test the ability of an intra-oral enamel slab system to measure erosion and to compare the erosive potential of a citric acid-based orange juice drink either with or without added CCM and a positive and negative control. Eleven adults wore an upper removable appliance for four periods each of 6 days. Each appliance held two enamel slabs which were inserted into the test drinks for 15 min 4 times a day for 6 days. Loss of enamel was quantified by profiling casts of the enamel slabs taken before and after the test period. Loss of enamal was greatest during exposure to a diet phosphoric acid-based cola drink (p < 0.001) but was similar during exposure to the two citric acid-based orange drinks, with or without CCM, and distilled water. The loss of surface enamel measured from a scanning electron micrograph agreed well with the measurement obtained by profilometry. It can be concluded that (a) the intra-oral enamel slab system was able to discriminate between drinks in their erosive potential, and (b) it was not possible to determine if CCM had any potential for reduction in erosion in an acid beverage as the level of erosion observed for both the critic acid-based orange drinks was not statistically significantly different from that observed with distilled water.

Clinical evaluation of paired compomer and glass ionomer restorations in primary molars: final results after 42 months

OBJECTIVES

To undertake a clinical trial comparing the efficiency of a compomer restoration with a glass ionomer restoration in the management of caries in primary molar teeth.

DESIGN

Subjects were admitted to the trial if they required at least one pair of restorations in primary molar teeth.

SETTING

Department of Child Dental Health, Newcastle Dental Hospital and School.

SUBJECT

Twenty nine children, aged 4-9 years, had 56 pairs of restorations placed between January 1995 and November 1997.

METHOD

The durability of the restorations was assessed during a 42-month follow-up period using modified United States Public Health Service criteria. Survival analysis and the McNemar paired test were used to compare the performance of the two restorative materials.

RESULTS

The compomer restorations had a higher mean survival time (42 months, SE 1.40) compared with 37 months (SE 1.90) for the glass ionomer restorations and this was significant at the 5% level. The compomer also performed significantly better in terms of anatomical form, marginal integrity, cavo surface discoloration and maintenance of interproximal contact.

CONCLUSIONS

The present trial demonstrated that Dyract compomer performed significantly better than Chemfil Superior a glass ionomer cement for all modified United States Public Health Service criteria over a period of 42 months.