Influence of fluoride availability of dentifrices on eroded enamel remineralization in situ.

Remineralization of eroded enamel by dentifrices containing similar sources/concentrations of fluoride was investigated in situ. Fifty-three subjects completed a double-blind crossover study with 3 randomly assigned dentifrice treatments: placebo (0 ppm F, PD); reference (1,450 ppm NaF, RD) and test (1,450 ppm NaF + 5% KNO(3), TD). Fluoride availability for each dentifrice was analyzed in vitro by standard tests (1-min fluoride release rate and enamel fluoride uptake). The subjects wore palatal appliances holding bovine enamel specimens previously eroded in vitro. Surface microhardness was determined before and after the in vitro erosive challenge, after in situ remineralization and after a second in vitro erosive challenge. ANOVA and pairwise comparisons were performed (alpha=0.05). TD was superior to RD in the fluoride release tests, but similar to RD in the enamel fluoride uptake test. The mean percent surface microhardness recovery was 21.9 (standard deviation 8.0) for PD, 28.6 (8.0) for RD and 36.0 (8.0) for TD. The mean percent relative erosion resistance change was -58.8 (12.7) for PD, -31.3 (12.7) for RD and -27.3 (12.6) for TD. Both fluoride-containing dentifrices provided superior remineralization (p<0.001) and erosion resistance (p<0.001) compared to PD. The percent surface microhardness recovery demonstrated by the TD was significantly greater than for the RD (p<0.001). There was no significant difference (p=0.073) between TD and RD in relative resistance to further erosive challenge. The results suggest that fluoride availability may be different in dentifrices with similar sources/concentrations of fluoride, providing different levels of remineralization of eroded enamel.

Evaluation of different fluoridated dentifrice formulations using an in situ erosion remineralization model.

OBJECTIVE: The objective of these three clinical in situ studies was to investigate the relative performance of commercially available and experimental dentifrice formulations, having different fluoride sources and excipient ingredients, at remineralizing a bovine enamel surface previously softened by a dietary acid challenge. METHODS: Each study utilized the same randomized, placebo-controlled, single-blind, crossover design. Subjects undertook single brushings of their natural teeth, with an in situ appliance in place, using different dentifrices in a randomly assigned order. Study A involved 58 subjects with the following dentifrices: Sensodyne Pronamel (1450 ppm F as NaF/5% KNO3); Blend-a-Med Classic (1450 ppm F as NaF); and a matched (Pronamel) placebo control (0 ppm F). Study B involved 56 subjects with the following dentifrices: Sensodyne Pronamel (1150 ppm F as NaF/5% KNO3); Crest Cavity Protection (1100 ppm F as NaF); Crest Pro-Health (0.454% SnF2 [1100 ppm F]/sodium hexametaphosphate); and a matched (Pronamel) placebo control (0 ppm F). Study C involved 56 subjects with the following dentifrices: Sensodyne Pronamel (1150 ppm F as NaF/5% KNO3); Sensodyne Pronamel Gentle Whitening (1150 ppm F as NaF/5% KNO3); Colgate Sensitive Multi Protection (1000 ppm F as NaMFP/5.53% potassium citrate/2% zinc citrate); and a matched (Pronamel) placebo control (0 ppm F). Subjects wore their palatal appliances holding eight bovine enamel blocks, previously exposed for 25 minutes to an in vitro erosive challenge with grapefruit juice, for the duration of the experiment. Five minutes after appliance insertion, subjects undertook a supervised, 90-second brush/rinse regimen with their assigned dentifrice. Surface microhardness (SMH) of the specimens was determined prior to the erosive challenge (baseline), after the in vitro erosive challenge, and were remeasured after four hours in situ remineralization following the tooth brushing event. Finally, SMH values were determined after a second in vitro erosive challenge at the end of the in situ remineralization period. Statistical analyses included ANOVA and pair-wise comparisons between treatments, testing at a 5% significance level. RESULTS: All three studies demonstrated significantly greater percent surface microhardness recovery (% SMHr) and percent relative erosion resistance (% RER) for dentifrices containing sodium fluoride compared to placebo controls. Overall, significantly greater % SMHr (p < 0.0001) was observed for Sensodyne Pronamel compared to Blend-a-Med Classic, Crest Pro-Health, and Colgate Sensitive Multi Protection dentifrices. Similarly, Sensodyne Pronamel delivered directionally better % RER vs. Blend-a-Med Classic (p = 0.0731), and significantly higher % RER vs. Crest Pro-Health (p = 0.0074) and Colgate Sensitive Multi Protection (p <0.0001). Crest Cavity Protection demonstrated significantly better % RER (p = 0.031) than Crest Pro-Health, which in turn demonstrated significantly better % RER than the placebo control (p < 0.0001). No other statistically significant between-product comparisons were observed. CONCLUSION: The results of these in situ studies support the effectiveness of dentifrices containing sodium fluoride to reharden enamel previously softened with an erosive challenge. Furthermore, these studies demonstrate the protective effects conferred to enamel, from erosion following the remineralization process in the presence of "ionic" fluoride. Under clinically relevant conditions, Sensodyne Pronamel and Sensodyne Pronamel Gentle Whitening offered superior anti-erosion performance compared to currently marketed dentifrice controls. These studies reinforce previous research indicating the importance of formulation effects on the relative remineralization performance of dentifrices under erosive conditions.

Dentinal hypersensitivity: a 12-week study of a novel dentifrice delivery system comparing different brushing times and assessing the efficacy for hard-to-reach molar teeth.

OBJECTIVE: This study was undertaken to confirm the efficacy of a novel 5% KNO3 gel-to-foam dentifrice, and to determine the effect of brushing duration on the relief offered from the novel dentifrice to subjects with sensitive molars. METHODS: This was a randomized, examiner-blind, two-arm, parallel-group, 12-week, longitudinal study of 141 subjects, stratified into four groups based on the number of sensitive teeth (< 6 or > or = 6) and the presence or absence of sensitive molars. Subjects brushed with the test product twice daily for either 45 seconds or two minutes for eight weeks, and then continued for four weeks with their regular dentifrice. At baseline, four, eight, and 12 weeks, subjects provided subjective evaluations of their sensitivity, and their sensitive teeth were stimulated by air and Yeaple probe. RESULTS: Both brushing groups and all four subgroups exhibited statistically significant reductions from baseline at each post-baseline visit in both their air and tactile sensitivity (p < 0.0001). Between-group comparisons revealed no statistically significant differences in air or tactile sensitivity among the groups. The two-minute group showed a small, but statistically significant increase in both air and tactile sensitivity four weeks after cessation of the test product (p < 0.04). At each post-baseline evaluation, statistically significant decreases from baseline were observed in both brushing groups for "maximum," "typical," and "minimum" subjective pain over the previous seven days (p < 0.001). There were no statistically significant differences between the brushing groups at any visit. For the subgroups with sensitive molars, there were significant decreases from baseline at each post-baseline visit, but no statistically significant differences between brushing groups. In the subgroups without sensitive molars, consistent reductions from baseline were only observed for "maximum" and "typical" pain levels, and at Week 4, the two-minute group had a statistically greater reduction in "minimum" pain level (p = 0.039). Both brushing groups and all four subgroups exhibited statistically significant reductions from baseline at each post-baseline visit in how much they were "bothered" by sensitivity in the previous week (p < 0.003). Between-group comparisons revealed no statistically significant differences. CONCLUSION: A novel gel-to-foam dentifrice with 5% potassium nitrate can provide significant reductions in dentinal hypersensitivity, and this effect extends to hard-to-reach molar teeth. This study confirms that with this new dentifrice technology, the desensitizing efficacy from a 5% KNO3 dentifrice is independent of brushing duration.

Evaluation of a desensitizing test dentifrice using an in situ erosion remineralization model.

OBJECTIVE: To evaluate, in an in situ remineralization model, the ability of a low abrasion fluoride dentifrice containing potassium nitrate to enhance the remineralization of enamel that was previously subjected to an in vitro dietary erosion challenge. METHODOLOGY: Thirteen subjects completed a single-blind (to specimen analyst) crossover design study with four randomly assigned dentifrice treatments: placebo dentifrice (0 ppm F; PD); dose response control dentifrice (250 ppm F; DD); clinically tested fluoride dentifrice (1100 ppm F; FD); and test dentifrice (1150 ppm F + 5% KNO3; TD). Each subject wore a palatal appliance holding eight bovine enamel blocks that were previously exposed for 25 minutes to an in vitro erosive challenge with grapefruit juice. Surface microhardness (SMH) was determined prior to the erosive challenge (baseline), after the in vitro erosive challenge, after in situ remineralization, and after a second in vitro erosive challenge. Statistical analyses included ANOVA and pair-wise comparisons between treatments, testing at a 5% significance level. RESULTS: The mean percent SMH recovery (SD) was 20.4 (7.7)a for PD; 27.4 (5.9)b for DD; 29.5 (8.9)bc for FD; 33.4 (6.7)c for TD. The mean percent net erosion resistance (SD) was -57.7 (10.8)a for PD; -41.3 (11.6)b for DD; -28.7 (9.7)c for FD; -23.6 (7.3)c for TD. Different superscript letters following the means imply statistically significant differences between groups for each response. CONCLUSION: The test dentifrice was shown to significantly enhance the remineralization of enamel previously subjected to an erosion challenge.

Obturator hernia: a new technique for repair.

An obturator hernia is exceedingly rare and the diagnosis is usually made at laparotomy for small bowel obstruction. Several methods of dealing with the hernial defect have been described. Two cases of obturator hernias in nonagenarians are reported and a new, simple and effective method of repairing the hernia by suturing a polypropylene (Prolene) mesh to Cooper's ligament is proposed.

Twenty-four-hour gastric luminal pH in normal subjects: influence of probe position, food, posture, and duodenogastric reflux.

OBJECTIVES: The aim of this study was to determine the gastric pH at different levels in the stomach under varying physiological circumstances. METHODS: Simultaneous 24-hour ambulatory gastric pH monitoring was performed with multiple electrodes in 24 normal subjects, divided into groups of six, to study the influence of food, the supine posture, and physiological duodenogastric reflux on gastric pH in different parts of the stomach. In 18 subjects, simultaneous recordings were made from two electrodes positioned 5 and/or 10 cm below the manometrically-defined lower border of the lower esophageal sphincter and, in six subjects, from three electrodes, one positioned 5 cm below the lower esophageal sphincter and two others positioned 5 and 8 cm proximal to the pylorus. RESULTS: During the daytime fasting period, pH was homogenous across the stomach with most time being spent between pH 1 and 2. Marked similarities in recorded pH were noted when two probes were placed in the stomach at the same level, indicating regional consistency in the pH of the chyme. This finding was observed when probes were free from each other or tethered together. Food increased pH most in the fundus, less in the midstomach, and least in the antrum. At night, when supine, alkaline shifts occurred in the distal stomach, most likely because of physiological duodenogastric reflux. These were commonly recorded in the antrum but only occasionally in the proximal stomach. CONCLUSIONS: Measurement of the gastric pH environment requires standardization of the probe position, of feeding, and of posture, and global measurement of gastric pH requires simultaneous recording in both the proximal and distal stomach.

Indications for laparoscopic formation of intestinal stomas.

A laparoscopic technique for formation of intestinal stomas is described and reported in four cases. The procedure has a role where difficulties with trephine stoma formation are anticipated, where simultaneous laparoscopic procedures are performed, and where accurate assessment of the extent of intra-abdominal malignancy is indicated.

An emergency daytime theatre list: utilisation and impact on clinical practice.

A prospective study of all weekday emergency surgery performed in a district general hospital over an 18-month period was undertaken to assess the impact of a fully staffed, daytime operating theatre for emergency surgery on night-time operating and on consultant supervision of trainees. In the 12 months following the introduction of the emergency list there was a 46% reduction in the number of general surgical operations performed after midnight compared with the preceding 6 months. Despite the increase in daytime operating the degree of consultant participation was unchanged, with the majority of emergency procedures being performed by unsupervised junior surgeons and anaesthetists. Although the emergency theatre was available to all specialties and was used for 'scheduled' and occasional 'elective' cases when there were no emergencies, only 37% of total theatre time was used. Without a change in consultant workload and practice which permits their increased involvement in emergency surgery, a dedicated daytime emergency theatre may be a costly measure which fails to fulfil all CEPOD recommendations.

Colonoscopic follow-up after resection for colorectal cancer: a selective policy.

A policy of selective colonoscopy after resection for colorectal cancer was evaluated to assess the benefit of detecting missed synchronous and metachronous tumours in patients under 70 years of age with a good prognosis, and the possible risk of missing such lesions in those not screened. With preoperative barium enema and palpation at laparotomy, synchronous cancers and adenomas were found in 2 and 28 per cent, respectively, of 275 consecutive patients undergoing resection. Eighty-five patients were selected for postoperative colonoscopy, which was repeated at least once in 32, there being a total of 60 repeat examinations. Adenomas, but no cancers, were found in 19 patients (22 per cent) on first screening, but on repeat colonoscopy early metachronous cancers were detected in three patients (9 per cent) and adenomas on 21 examinations (35 per cent). Only one of the patients followed by clinical examination developed a symptomatic tumour. This suggests that postoperative colonoscopy is unlikely to benefit the majority but may be extremely important for young fit patients with continuing polyp formation who are at high risk of developing metachronous cancer.

Role of intragastric and intraoesophageal alkalinisation in the genesis of complications in Barrett's columnar lined lower oesophagus.

Patients with Barrett's columnar lined lower oesophagus have severe acid gastrooesophageal reflux and may develop complications, including ulceration, stricture, and carcinoma. The aim of this study was to establish if a relationship exists between the pH profile in the oesophagus and stomach and the development of complications in patients with Barrett's columnar lined lower oesophagus. Twenty four hour ambulatory oesophageal pH monitoring was performed in 26 patients with Barrett's columnar lined lower oesophagus and combined with 24 hour ambulatory gastric pH monitoring in 16. Ten of the 26 with Barrett's columnar lined lower oesophagus had complications including stricture (eight), deep ulceration (one), and carcinoma (one). Oesophageal acid exposure (% time < pH 4) was similar in patients with or without complications (19.2% v 19.3% p > 0.05). Oesophageal alkaline exposure (% time > pH 7) was greater in patients with complications (24.2% v 8.4% p > 0.05). Of the 16 patients who underwent gastric pH monitoring there was a clear relationship between gastric and oesophageal alkalinisation in 13. These results support the hypothesis that complications in Barrett's columnar lined lower oesophagus develop in association with increased exposure of the oesophagus to an alkaline environment which appears to be secondary to duodenogastric reflux. The routine use of 24 hour ambulatory gastric pH monitoring in conjunction with oesophageal pH monitoring can help identify those patients at risk.

Barrett's oesophagus: effect of antireflux surgery on symptom control and development of complications.

Forty-five patients with histologically proven Barrett's columnar-lined oesophagus (CLO) were treated in one unit over a 9-year period. Patients were studied prospectively as part of a surveillance programme; all initially received standard conservative treatment including high-dose H2-receptor antagonists. A satisfactory initial response was seen in 21 patients, but in 24 the symptoms were unchanged or progressed; 19 patients in the latter group were considered suitable for antireflux surgery and underwent fundoplication. Symptoms of heartburn or dysphagia persisted or recurred in 88 per cent of patients receiving medical treatment alone and complications developed in 38 per cent, including nine strictures and one adenocarcinoma. In patients undergoing antireflux surgery, symptoms persisted or recurred in 21 per cent and complications developed in 16 per cent (P < 0.01). Complete regression of Barrett's CLO occurred in two patients (11 per cent) after antireflux surgery. The results of this study suggest the superiority of antireflux surgery over pharmacological acid suppression in the control of symptoms and prevention of complications in patients with Barrett's CLO.

Complications of gastroesophageal reflux disease. Role of the lower esophageal sphincter, esophageal acid and acid/alkaline exposure, and duodenogastric reflux.

The factors contributing to the development of esophageal mucosal injury in gastroesophageal reflux disease (GERD) are unclear. The lower esophageal sphincter, esophageal acid and acid/alkaline exposure, and the presence of excessive duodenogastric reflux (DGR) was evaluated in 205 consecutive patients with GERD and various degrees of mucosal injury (no mucosal injury, n = 92; esophagitis, n = 66; stricture, n = 19; Barrett's esophagus, n = 28). Manometry and 24-hour esophageal pH monitoring showed that the prevalence and severity of esophageal mucosal injury was higher in patients with a mechanically defective lower esophageal sphincter (p less than 0.01) or increased esophageal acid/alkaline exposure (p less than 0.01) as compared with those with a normal sphincter or only increased esophageal acid exposure. Complications of GERD were particularly frequent and severe in patients who had a combination of a defective sphincter and increased esophageal acid/alkaline exposure (p less than 0.01). Combined esophageal and gastric pH monitoring showed that esophageal alkaline exposure was increased only in GERD patients with DGR (p less than 0.05) and that DGR was more frequent in GERD patients with a stricture or Barrett's esophagus. A mechanically defective lower esophageal sphincter and reflux of acid gastric juice contaminated with duodenal contents therefore appear to be the most important determinants for the development of mucosal injury in GERD. This explains why some patients fail medical therapy and supports the surgical reconstruction of the defective sphincter as the most effective therapy.

Effect of duodenal switch procedure on gastric acid production, intragastric pH, gastric emptying, and gastrointestinal hormones.

The duodenal switch operation preserves the pylorus and the proximal 3 to 7 cm of duodenum in continuity with the stomach while diverting pancreaticobiliary secretions. We compared it with the Roux-en-Y without vagotomy or antrectomy in 12 dogs with innervated gastric pouches. Acid secretion was inhibited between tests using ranitidine in the Roux-en-Y group only, but two of the six dogs still developed stomal ulcers and the remainder showed stomal hyperemia. This may be due to a significant increase in gastric acid output after Roux-en-Y, but gastric emptying and plasma gastrin, cholecystokinin, secretin, gastric inhibitory polypeptide, peptide YY, and neurotensin were similar after both procedures. In 12 patients and a further 6 dogs, the duodenal switch caused no significant change in the intragastric pH environment as assessed by intragastric pH monitoring. The duodenal switch is a suitable procedure for pancreaticobiliary diversion.

A more physiological alternative to total fundoplication for the surgical correction of resistant gastro-oesophageal reflux.

The incidence of mechanical complications associated with the Nissen fundoplication has prompted evaluation of an anti-reflux procedure designed to be simpler and more physiological, and encompassing a broader view of the many factors involved in the anti-reflux mechanism. Preliminary assessment of the first 100 patients with a mean follow-up of 3.5 years showed symptomatic improvement in 96 per cent and complete relief in 85 per cent. A further 100 patients were studied using formal symptom scoring, endoscopy, manometry and pH monitoring performed before operation and 3 months after operation. Similar clinical results were accompanied by improvement in endoscopic oesophagitis in 95 per cent, complete healing in 74 per cent and restoration of the pH profile to physiological levels in 84 per cent. Troublesome mechanical complications comprised a 2 per cent incidence of dysphagia, but there was no gas bloat or inability to belch or vomit, which may relate to the restoration of lower oesophageal sphincter characteristics close to those of 30 asymptomatic controls. The procedure is simpler to perform than total fundoplication, is well tolerated and is applicable to patients with reflux stricture and impaired oesophageal body motility. The results of this study support the hypotheses that effective reflux control can be achieved without total fundoplication by attention to several factors of known relevance to the anti-reflux mechanism, and that restoration of characteristics of the lower oesophageal sphincter close to physiological levels results in a lower incidence of mechanical complications.

Computerized identification of pathologic duodenogastric reflux using 24-hour gastric pH monitoring.

Duodenogastric reflux is a naturally occurring sporadic event, the incidence, occurrence, and detrimental effects of which have been difficult to assess. The reliability of 24-hour gastric pH monitoring to detect duodenogastric reflux was studied. Central to the use of pH monitoring for this purpose is confidence in its ability to measure and display pH data in a way that reflects changes in the gastric pH environment with sufficient sensitivity. To test this the gastric pH of 10 dogs was measured in the fasting state, after feeding, and after pentagastrin stimulation. The antrum was more alkaline in the fasting state (p less than 0.01) and the display of data by frequency distribution graph was sensitive enough to reflect induced pH changes. To test the consistency of gastric pH at a given position, simultaneous 24-hour gastric monitoring was performed in 12 normal subjects with two probes placed at either 5 or 10 cm below the lower esophageal sphincter. Only at the 5-cm position did the two probes read within 1 pH unit of each other more than 90% of the time. Based on these principles, gastric pH monitoring was performed 5 cm below the lower esophageal sphincter in 30 normal subjects and 11 patients, fulfilling Ritchie's clinical criteria for pathologic duodenogastric reflux. The data obtained was arranged into 71 variables and subjected to discriminant analysis. Sixteen variables were identified, each with a corresponding coefficient to be used as a multiplier to derive a score. A score of more than +2.2 indicated a high probability of pathologic duodenogastric reflux. The test was applied to a validation population consisting of 10 additional normal subjects and 10 patients meeting Ritchie's criteria. All normal subjects had a normal score and all but one (90%) of the patients had an abnormal score. When compared to O-diisopropyl iminodiacetic acid (DISIDA) scintigraphy in another group of 22 normal subjects and 60 patients, 24-hour gastric pH monitoring was superior in the detection of pathologic duodenogastric reflux. The study shows how the application of computer technology can be used to diagnose pathologic duodenogastric reflux in patients with complex foregut complaints.

A new technique to define and clarify esophageal motor disorders.

Ambulatory 24-hour esophageal manometry was applied to analyze motility in 12 normal subjects and 9 patients with chest pain and dysphagia caused by diffuse esophageal spasm (DES). Pain episodes characterized by nonperistaltic activity occurred in 7 of 9 patients. A score based on 10 variables of the motility pattern differentiated patients from normal subjects and quantitated the severity of the disorder. Ambulatory motility monitoring was prospectively performed in 8 normal subjects and 37 patients: 8 with DES, 13 with hypertensive contractions, and 16 with a nonspecific disorder on standard manometry. The score was positive in 6 of 8 patients with DES and negative in all normal subjects (accuracy 87 percent). Nine of the 13 patients with hypertensive contractions (70 percent) and 6 of 16 with nonspecific disorders (38 percent) had a pathologic score reflecting a dysmotility as severe as DES. Ambulatory esophageal manometry is a more physiologic way to identify a motor disorder than standard manometry and has the potential to improve selection of patients for a surgical myotomy.

Alkaline gastroesophageal reflux: implications in the development of complications in Barrett's columnar-lined lower esophagus.

Barrett's esophagus is a common finding in patients with gastroesophageal reflux and is associated with a high incidence of serious complications (stricture, ulceration, and carcinoma). The reason that only a portion of patients with reflux develop Barrett's esophagus and why some are prone to develop complications is unknown. Twenty-three patients with Barrett's esophagus underwent endoscopy, 24-hour esophageal pH monitoring, and manometry. Nine of these patients with gastritis underwent 24-hour gastric pH monitoring, and three with symptoms of duodenogastric reflux underwent 99mTc-labeled hepato-iminodiacetic acid scanning. Patients with complicated (n = 12) and uncomplicated (n = 11) Barrett's esophagus were compared with each other and with patients with reflux esophagitis (n = 53) and normal volunteers (n = 50). Patients with Barrett's esophagus showed an increased exposure to acid and alkaline gastric juice compared with patients with esophagitis and normal volunteers. In the patients with Barrett's esophagus with and without complications, there was no significant difference in age, incidence of defective lower esophageal sphincter, incidence of defective peristalsis, extent of the Barrett's epithelium, or percent time the esophageal pH was less than 4. In contrast, the percent time the esophageal pH was greater than 7 was significantly greater in patients with complications. This alkaline exposure is likely to be related to duodenogastric reflux. This was supported by positive gastric pH scores for duodenogastric reflux and 99mTc-labeled hepato-iminodiacetic acid scans in patients with Barrett's complications. These findings suggest that the development of complications in Barrett's esophagus is the result of the damaging effect of refluxed duodenal juice.