Response of Esophageal Epithelium to Acute and Chronic Stress in Rabbits.

We studied electrophysiological changes in rabbit esophageal epithelium following acute (AS) and chronic stress (CS). Esophageal tissue was placed in Ussing chamber and the potential difference U between the luminal and abluminal sides, the short-circuit current Isc, as well as the tissue resistance R were measured. The initial values of these parameters for each sample were determined after the samples were stabilized in Ringer solution. Then, the tissues were exposed for 1 h to normal Ringer solution or Ringer solution with pH 4.0 and pH 1.7 with or without pepsin (0.25 mg/ml). Fluorescein was added to the luminal side of the sample to measure its permeability. In the AS group, U at Ringer solution (pH 1.7)+pepsin was significantly decreased in comparison with the baseline and control values (by 46 and 22%, respectively, p<0.05). R decreased by 74% in comparison with baseline, which little differed from the decrease in control samples exposed to Ringer solution (pH 1.7)+pepsin (by 62%). CS did not change U relative to baseline values, while changes in R were similar to those in the AS group. In the AS group, the permeability of the esophageal tissue perfused with Ringer solution (pH 1.7)+pepsin was significantly higher than in both the control and CS groups. AS, but not CS, made the esophageal epithelium more sensitive to the effects of noxious agents, disrupted barrier properties, and increased permeability. The effects of stress on gastroesophageal reflux disease symptoms can be related to severe exposure to acid and/or pepsin; however, the mechanisms other than epithelial defense should be evaluated.

Inflammatory markers predict insulin sensitivity in active rheumatoid arthritis but not in psoriatic arthritis.

Whether the insulin resistance commonly observed in patients with inflammatory arthritis is a disease-specific feature and/or is limited to a disease phase (i.e., it occurs only during phases of high disease activity) is unknown. Fifty-three rheumatoid arthritis (RA) and 44 psoriatic arthritis (PsA) patients were recruited consecutively along with 194 controls matched for age, sex and body mass index for a case-control study. All underwent an oral glucose tolerance test, the results of which were analysed to derive the following indexes: homeostatic model of insulin resistance (HOMA-IR), insulin sensitivity index (ISI) and early insulin sensitivity index (EISI). These data were related to anthropometric, clinical and laboratory findings. Metabolic parameters of patients and controls were similar. Neither inflammatory markers nor disease activity scores were related to glucose metabolism for the generality of RA and PsA patients; however, by restricting the analysis to the subset of RA patients with residual disease activity, an association emerged between erythrocyte sedimentation rate, on the one hand, and fasting insulin (ß=0.46, p=0.047) and HOMA-IR (ß=0.44, p=0.02), on the other. Moreover, C-reactive protein (CRP) levels were associated with plasma glucose and insulin levels measured 120 min after the glucose load (ß=0.91, p=0.0003 and ß=0.77, p=0.0006, respectively); ISI and EISI were predicted by CRP (ß=-0.79, p=0.0006; ß=-0.80, p=0.0001, respectively). The same did not hold true for PsA patients. The association between systemic inflammation and insulin resistance indexes is a feature of RA with residual disease activity, not a universal feature of inflammatory arthritides.

Curriculum for neurogastroenterology and motility training: A report from the joint ANMS-ESNM task force.

Although neurogastroenterology and motility (NGM) disorders are some of the most frequent disorders encountered by practicing gastroenterologists, a structured competency-based training curriculum developed by NGM experts is lacking. The American Neurogastroenterology and Motility Society (ANMS) and the European Society of Neurogastroenterology and Motility (ESNM) jointly evaluated the components of NGM training in North America and Europe. Eleven training domains were identified within NGM, consisting of functional gastrointestinal disorders, visceral hypersensitivity and pain pathways, motor disorders within anatomic areas (esophagus, stomach, small bowel and colon, anorectum), mucosal disorders (gastro-esophageal reflux disease, other mucosal disorders), consequences of systemic disease, consequences of therapy (surgery, endoscopic intervention, medications, other therapy), and transition of pediatric patients into adult practice. A 3-tiered training curriculum covering these domains is proposed here and endorsed by all NGM societies. Tier 1 NGM knowledge and training is expected of all gastroenterology trainees and practicing gastroenterologists. Tier 2 knowledge and training is appropriate for trainees who anticipate NGM disorder management and NGM function test interpretation being an important part of their careers, which may require competency assessment and credentialing of test interpretation skills. Tier 3 knowledge and training is undertaken by trainees interested in a dedicated NGM career and may be restricted to specific domains within the broad NGM field. The joint ANMS and ESNM task force anticipates that the NGM curriculum will streamline NGM training in North America and Europe and will lead to better identification of centers of excellence where Tier 2 and Tier 3 training can be accomplished.

Effect of alginate in patients with GERD hiatal hernia matters.

Alginate-based formulations are frequently used as add-on proton pump inhibitor (PPI) therapy to help control of heartburn and regurgitation. There are limited data regarding the mechanisms and effects of alginate-based formulations. We aimed to evaluate the effects of the sodium alginate intake and its likely temporal relations on intraesophageal reflux events by MII-pH in patients with and without hiatal hernia (HH). Fifty GERD patients (18 with HH, 32 without HH) with heartburn or regurgitation once a week or more common were included. After combined multichannel intraluminal impedance and pH-metry (MII-pH) had been performed, all patients were asked to eat the same standard meal (double cheeseburger, 1 banana, 100 g regular yoghurt, and 200 mL water with total energy value of 744 kcal: 37.6% of carbohydrates, 21.2% of proteins, and 41.2% of lipids) during two consecutive days. On separate random two consecutive days, all patients took 10 mL of sodium alginate (GA; Gaviscon Advance; Reckitt Benckiser Healthcare, Hull, UK) or 10 mL of water, 30 minutes after the refluxogenic meal. After eating refluxogenic meal, patients were examined ½ hour for basal conditions, 1 hour in upright, and 1 hour in supine positions. Alginate significantly decreased acid reflux after intake at the first hour in comparison to water in patients with HH (6.1 vs. 13.7, P = 0.004) and without HH (3.5 vs. 5.5, P = 0.001). Weakly acid reflux were increased at the first hour in patients with HH (3.4 vs. 1.3, P = 0.019) and without HH (1.7 vs. 5, P = 0.02) compared to water. There was no distinctive effect of alginate on the height of proximal migration of reflux events in patients with HH and without HH. Alginate decreases acid reflux events within a limited time period, especially at the first hour both in patients with and without HH. Alginate has no effect on the height of reflux events along the esophagus both in patients with and without HH.

Prevalence of gastroesophageal reflux disease in Moscow.

Limited data exist to determine the prevalence and clinical spectrum of gastroesophageal reflux disease (GERD) in the Russian population, which might be different from those in Western countries. This study was performed in Moscow on randomized 1065 adults aged ≥ 15 years. A validated reflux questionnaire comprising 72 questions and an additional 29 sub-questions were used. The questions assessed (heartburn and regurgitation) and related (dyspepsia, dysphagia, odynophagia and chest pain) symptoms, the triggering factors of these symptoms, family history and data on demographic and socioeconomic features. GERD was defined as heartburn and/or regurgitation once a week or common. Of the 1065 participants, 42.1% were male and 57.9% were female. The prevalences of frequent and occasional symptoms were 17.6 and 22.1% for heartburn and 17.5 and 21.8% for regurgitation, respectively, over the last 12 months. The prevalence of GERD was found to be 23.6%. The rate of GERD was significantly higher in females than in males (15.4 vs. 29.5%, P < 0.001) and significantly increased as the age of the participants increased (P = 0.011). GERD was present in 20.4% of smokers, 24.2% of coffee drinkers, 21.5% of alcohol consumers and 45.9% of stressed participants. Although the rate of alcohol consumers was lower in those with GERD compared with those without GERD, the rate of coffee drinkers and stressed participants was higher among those with GERD. The rate of additional symptoms was higher even in participants complaining of regurgitation/heartburn rarely, compared with those without complaints. Using the same questionnaire, which makes it possible to compare the present results with those from different countries, we found the prevalence of GERD in Moscow to be 23.6%, one of highest in the Western populations. The rates of heartburn and regurgitation were found to be similar, which constitutes a different result than has been found in similar studies. Additional symptoms should be assessed, in all GERD patients even in the presence of rare complaints of regurgitation/heartburn.

Novel esophageal speech therapy method in total laryngectomized patients: biofeedback by intraesophageal impedance.

The loss of the best communication port after total laryngectomy surgery makes speech rehabilitation an important goal. Our aim was to improve the quality of esophageal speech (ES) using online esophageal multichannel intra-luminal impedance (MII) as a new biofeedback method. Twenty-six total laryngectomized patients were included. Before ES therapy, an esophageal motility test was carried out. MII catheters were placed in all subjects who were then randomized into two groups. Group 1 included 13 cases, who were retrained according to the classical method. Group 2 included 13 cases, who were retrained according to the simplified animation of air movements within the esophagus and upper stomach resulting from the modifications of intra-esophageal air kinetics gained by MII. The level of speech proficiency was evaluated relative to pretraining levels using perceptual scales in the third and sixth months. Acoustic voice was analyzed. The number of syllables read per minute and the intelligibility of monosyllabic and dissyllabic words were calculated. In this study, MII was used for the first time in alaryngeal speech rehabilitation as a biofeedback method; an overall sufficient speech level was achieved by 68.4% at the end of therapy, whereas attendance was 90%. A statistically significant improvement was found in both groups in terms of ES level compared with the pretraining period although there was no significant difference between groups. Although we did not observe the expected difference between groups suggested by our hypothesis, MII may be used as an objective tool to show patients how to swallow and regurgitate air during training, and may thus expedite ES therapy both for the speech therapist and the patient in the future.

Predictive value of esophageal motility test in the proficiency of esophageal speech.

One method of speech rehabilitation following total laryngectomy surgery is esophageal speech therapy (EST). In this method, which has witnessed relatively low success rates at the end of therapy, identification of patients who can benefit from EST beforehand will be important for determining the appropriate method for alaryngeal speech rehabilitation and might be cost-effective, saving time and labor. To this end, this study conducted research on the feasibility of manometric data measured prior to therapy using an esophageal motility test (EMT) in order to determine the candidates most suitable for esophageal speech (ES) beforehand. A total of 51 total laryngectomy male patients who had never been subject to any kind of speech rehabilitation and had always been articulate were included in the study. Data were collected from 44 patients who completed EST, lasting for 6 months in total and consisting of 11 sessions. Manometric measures were obtained through EMT using a water-perfusion system with a Dent sleeve catheter on the patients prior to the therapy. Wepman's scale was used in order to evaluate ES proficiency. Following the therapy, in accordance with this scale, while patients whose scores was 1, 2, or 3 were considered as adequate, those whose scores were 4, 5, 6, or 7 were considered inadequate and were divided into two groups. Manometric correlations were analyzed between 17 patients (group I) who were able to perform ES at an adequate level and 27 patients (group II) who could not. No statistically significant difference between the groups could be observed in terms of average pressure generated within the upper and lower esophageal sphincters obtained through EMT, peak amplitude of esophageal body contraction pressure, contraction duration time, onset velocity, or peak velocity values. EMT conducted prior to application of EST to total laryngectomized patients did not have any value in determining the level of ES that a patient could reach. Our results also suggest that sphincter pressures or esophageal motility patterns do not have any predictive value and should not be performed.

The effect of laparoscopic Nissen fundoplication on laryngeal findings and voice quality.

BACKGROUND: This study aimed to report the need for an ear, nose, and throat (ENT) specialist to evaluate the laryngeal findings and the voice quality of patients with gastroesophageal reflux disease (GERD) and laryngopharyngeal reflux (LPR) symptoms before and after surgery. METHODS: For this study, 38 GERD patients who had a Reflux Symptom Index (RSI) score higher than 14 underwent complete assessment in the ENT department. Standard 24-h pH monitoring, esophageal motility assessment, a detailed ENT examination including the RSI, the Reflux Finding Score (RFS), and objective voice analysis were performed for all the patients before reflux surgery, then 6 to 8 months afterward. RESULTS: The subject's mean RSI scores were 25.45 +/- 7.5 before and 16.52 +/- 5.06 after surgery (p < 0.05), and the mean RFS scores were, respectively, 10.37 +/- 2.7 and 5.5 +/- 1.45 (p < 0.05). The pre- and postoperative differences in the RSI and RFS scores and the voice parameters were statistically significant. CONCLUSIONS: Objective voice analysis, RSI, and RFS can be used to evaluate the postoperative results for GERD patients with LPR symptoms. Examination of these patients by an ENT specialist is necessary before and after the operation.

Eosinophil infiltration of the oesophageal mucosa in patients with pollen allergy during the season.

BACKGROUND: The oesophagus is normally devoid of eosinophils. There are some disorders accompanying with eosinophil infiltration. Food allergy has been reported as a common reason, especially in children but some other studies have also indicated that aeroallergens might have a role in oesophageal eosinophil accumulation. OBJECTIVE: In this study we investigated whether there is any eosinophil recruitment in the oesophagus of pollen-allergic patients who had respiratory symptoms during the season. METHODS: Thirty-eight symptomatic patients (allergic rhinitis (AR) with or without asthma) who had sensitization to grass pollen were included in the study during the pollen season. Controls were composed of 25 healthy non-atopics and 24 patients diagnosed as having gastro-oesophageal reflux disease. Reflux was excluded in allergic and non-atopic groups, whereas the presence of allergy was eliminated in control groups. Gastrointestinal endoscopy was performed in all participants, and biopsy specimens were taken from both the proximal and the distal oesophagus to evaluate eosinophil accumulation. At the same time, blood eosinophil numbers were counted. Results Oesophageal eosinophil accumulation was found in 10 allergic patients (26%) and in five patients (21%) with gastro-oesophageal reflux disease but none of the healthy controls had eosinophils (0%) (P<0.05). Blood eosinophils were higher in these 10 patients than the rest of the 28 patients without infiltration. In this group, blood eosinophils were also correlated with the number of accumulated eosinophils in the oesophagus (P<0.001). There was more intense eosinophil infiltration at the distal part of the oesophagus in the reflux group when compared with the allergic group (mean 7.6+/-5.6 vs. 3.2+/-3.7). Nevertheless, eosinophils were found to be concentrated (mean 5.5+/-7.3) in the proximal oesophagus of allergic patients, although it was 1.7+/-1.5 in reflux patients (P>0.05). Conclusion Our results showed that eosinophil infiltration might be observed in oesophageal tissue of patients with respiratory tract allergy during the symptomatic period. This finding may possibly reflect the systemic and common mucosal aspects of allergic inflammation.

Psychometric and methodological characteristics of a culturally adjusted gastroesophageal reflux disease questionnaire.

Population-based data regarding the prevalence of gastroesophageal reflux disease (GERD) in Turkey is lacking. Therefore, a valid and reliable instrument for population-based study of GERD is important. The purpose of the study is to establish the feasibility, reproducibility, reliability and validity of the Turkish version of the GERD questionnaire. The study sample of 630 people was randomly recruited from the 20- to 65-year-old-population of Menderes, Izmir. Face to face interviews were conducted using the Turkish GERD questionnaire. The questionnaire was translated into Turkish, and then test-retest reliability of the study was carried out with 25 individuals. Internal reliability was measured using Cronbach's alpha. Additionally, a validity study was performed at the gastroenterology outpatient clinic at Ege University, Faculty of Medicine (45 people). This Turkish GERD questionnaire was easily understood and completed in a reasonable time by members of the population for whom the survey was intended. For all questions (omitting the demographic questions) kappa statistics were calculated; the median kappa for the outpatient assessment was 0.82. The sensitivity of the questionnaire concerning heartburn was strong and the specificity of the test was weak. By calculating Cronbach's alpha coefficient, we estimated the internal consistency or the reliability of each component. The Cronbach's alpha coefficients were above 0.70. This instrument can be used for large-scale population based studies in Turkey.

Eosinophilic bronchitis as a cause of chronic cough.

Eosinophilic bronchitis is a recently described condition in patients with chronic cough, sputum eosinophilia, normal spirometry and no evidence of bronchial hyperreactivity. The aim of the study was to assess the causes of chronic cough and to identify the prevalence of eosinophilic bronchitis as a cause of chronic cough. Thirty-six patients [mean age 45.4 +/- 14.3 years (range 16-69 years), M/F: 4/32] with an isolated chronic cough lasting for more than 4 weeks were recruited from the outpatient clinic. In all patients, after a full history and physical examination, blood eosinophil count, eosinophilic cationic protein (ECP), serum total and specific IgE levels were measured. Spirometry, methacholine provocation test, skin prick tests, ear, nose and throat examination, induction of sputum and esophageal pH testing were performed. The mean duration of cough was 31.3 +/- 52.3 months. Sputum eosinophilia greater than 3% was present in 12 (33.3%) patients and they were diagnosed as eosinophilic bronchitis. Their induced sputum had a mean eosinophil count of 8.3% and a mean ECP level of 98.5 mg x l(-1), which were higher than the others (P=0.003, both). The diagnosis of the remaining patients were postnasal drip syndrome in eight, gastroesophageal reflux disease in eight, post-infectious cough in two and cough-variant asthma in one patient. In conclusion, eosinophilic bronchitis is an important cause of chronic cough and should be considered in the assessment of patients before regarding them as having idiopathic chronic cough.

Esophageal exposure to ethanol increases risk of acid damage in rabbit esophagus.

Heavy alcohol consumption is associated with the development of reflux esophagitis. Among the reasons for this are impairment of the antireflux barrier, stimulation of acid secretion, and altered tissue resistance. To explore the contribution of altered tissue resistance to the development of esophagitis, sections of rabbit esophageal epithelium were mounted in Ussing chambers and exposed luminally to 10% ethanol, acid (HCl, pH 2), or combinations of both. Tissue injury was assessed by measurements of potential difference (PD), short circuit current (Isc) and electrical resistance (R) and by histology. Tissues exposed luminally to HCl for 1 hr exhibited little or no change electrically or morphologically compared to Ringer controls, while luminal exposure to 10% ethanol for 1 hr lowered PD (53 +/- 4%), Isc (30 +/- 1%), and R (31 +/- 5%) and produced cellular edema in the upper layers. Simultaneous exposure to ethanol and acid resulted in significantly greater declines in PD (81 +/- 1%) and Isc (70 +/- 2%), but not R (40 +/- 4%), and greater morphologic damage. Moreover, this vulnerability of ethanol-exposed tissues to acid was demonstrable at generally innocuous levels of acidity (pH 2-4), after only short periods of ethanol exposure (10 min) and with delays for acid exposures of up to 1 hr following ethanol removal from the bathing solution. In conclusion, ethanol has a direct noxious effect on esophageal epithelium, which predisposes the tissue to acid injury. Tissue vulnerability develops with even short exposures to clinically relevant concentrations of ethanol, lasts for at least 1 hr after ethanol clearance, and transforms relatively innocuous concentrations of acid into damaging agents. These results support the likelihood that ethanol's ability to alter tissue resistance plays an important role in the development of reflux esophagitis in humans.

Mechanisms of basolateral Na+ transport in rabbit esophageal epithelial cells.

We examined the mechanisms of cellular Na+ transport, both Cl- dependent and Cl- independent, in the mammalian esophageal epithelium. Rabbit esophageal epithelium was dissected from its muscular layers and mounted in a modified Ussing chamber for impalement with ion-selective microelectrodes. In bicarbonate Ringer, transepithelial potential difference was -14.9 +/- 0.9 mV, the transepithelial resistance (RTE) was 1,879 +/- 142 Omega. cm2, the basolateral membrane potential difference (VmBL) was -53 +/- 1.5 mV, and the intracellular activity of Na+ (aNai) was 24.6 +/- 2.1 mM. Removal of Na+ and Cl- from the serosal and luminal baths decreased aNai to 6.6 +/- 0.6 mM. Readdition of Na+ to the serosal bath in the absence of Cl- increased aNai by 21.8 +/- 3.0 mM, whereas VmBL and RTE remained unchanged. When serosal Na+ was readded in the presence of amiloride the increase in aNai and the rate of Na+ entry were decreased by approximately 50%. 5-(N-ethyl-N-isopropyl)amiloride mimicked the effect of amiloride, whereas phenamil did not. Subsequent readdition of Cl- to the serosal bath further increased aNai by 4.4 +/- 1.9 mM. When the cells were acid loaded by pretreatment with NH+4 in nominally HCO-3-free Ringer, intracellular pH measurements showed a pHi recovery that is dependent on the presence of Na+ in the serosal bath and that can be blocked by amiloride. These data indicate that esophageal epithelial cells possess a Na+-dependent, amiloride-sensitive electroneutral mechanism for Na+ entry consistent with the presence of a basolateral Na+/H+ exchanger. The ability of Cl- to further enhance Na+ entry supports the existence of at least one additional Cl--dependent component of basolateral Na+ entry.

Is administration of n-3 fatty acids by mucosal enema protective against trinitrobenzene-induced colitis in rats?

We investigated the protective role of fish oil (FO-source of n-3 FA) enriched diet (in the first protocol) in 20 rats and FO administration intrarectally (in the second protocol) in 40 rats with trinitrobenzene (TNB) colitis. All colonic specimens were pathologically evaluated, myeloperoxidase enzyme activities were measured, leukotriene B4 (LTB4) and LTC4 levels were determined by radioimmunoassay. In the first protocol 10 rats (group A1) were fed with 8% sunflower and cotton oil enriched diet and (group A2) with 8% FO enriched diet for 6 weeks. At the end of this period, TNB (30 mg in 0.25 ml of 30% ethanol) were intrarectally administered. After 2 weeks, rats were sacrificed. MPO activities (2.47 versus 30.17), LTB4 (34.5 versus 903.3) and LTC4 (77.7 versus 456.0) levels were significantly reduced in group A2 compared with group A1 (P<0.005). There was also a significant difference in pathologic scores (1.55 versus 2.12, P<0.002) between two groups. In the first part of the second protocol, 20 male rats were randomized into two equal groups (B1 and B2) and TNB colitis was induced. After 1 day, 1 ml of saline (group B1) or n-3 FA enemas (group B2) were administered every day for 2 weeks. At the end of this period, rats were sacrificed and evaluated as done for previous groups. Although there was no significant difference between the two groups in comparison with MPO enzyme activities and pathologic scores, the LTB4 (130.1 versus 971.0) and LTC4 (126.0 versus 532.0) levels of FO group were significantly reduced (P<0.005). In the second part of the second protocol, 20 male rats were randomized into two groups. One millilitre of saline (group B3) or FO enemas (group B4) were administered to rats every day for 3 days. At the fourth day, TNB-colitis was induced and after 24 h rats were sacrificed. We could not find any significant difference in MPO activities, pathologic scores, LTB4 and LTC4 levels between groups B3 and B4. In conclusion, FO enriched diet decreased both pathologic damage and tissue LT levels. The second protocol of our study revealed that the long-term FO enemas decreased the LTB4 and LTC4 levels; however, did not have any beneficial effect on the tissue lesions. Short periods of FO enemas did not have a protective role in the occurrence of experimental colitis. The present study showed that FO enemas significantly decreased LT levels. The protective effect of FO (oral and enema) in TNB colitis may open a new insight into the treatment of inflammatory bowel disease.

Effect of ethanol on the structure and function of rabbit esophageal epithelium.

Epidemiological studies indicate a relationship between alcohol consumption and esophageal epithelial disease. We therefore sought the contribution of the direct effects of ethanol on esophageal epithelial structure and (transport and barrier) function. Epithelium from the rabbit was mounted in Ussing chambers and exposed luminally for 1 h to 1-40% ethanol. At concentrations of 1-5% potential difference (PD) increased, and at 10-40% PD decreased. The increase in PD with 1-5% ethanol was accompanied by an increase in short-circuit current (Isc), and this increase in Isc could be blocked by ouabain pretreatment. The decrease in PD with 10-40% ethanol was associated with a decrease in electrical resistance (R), and this decrease in R was paralleled by an increase in transepithelial [14C]mannitol flux. Reversibility of these changes was limited at ethanol concentrations > or = 10%, and these were associated morphologically by patchy or diffuse tissue edema. Moreover, as with ethanol exposure in vitro, exposure in vivo produced dose-dependent changes in PD, Isc, R, and morphology. These observations indicate that exposure to ethanol in concentrations and under conditions reflecting alcohol consumption in humans can alter and impair esophageal epithelial transport and barrier functions. Such impairments are likely to contribute to the observed increase in risk of esophageal disease with regular consumption of alcoholic beverages.

A biomechanical comparison between original and used titanium miniplates.

Four dogs were chosen for this study. An experimental fracture was made in the mandibular symphysis region of each dog. Two miniplates and eight screws were applied, and removed three and six months postoperatively. In this study, the surface and mechanical characteristics of titanium miniplates were evaluated. Study materials consisted of four groups. In each of the groups, there were six miniplates. The groups are as follows: Group A: Original plates (not used) as a control (i.e. used as a reference in comparisons) Group B: Original plates bent as in operation but not left in tissue Group C: Plates removed at third month postoperatively Group D: Plates removed at sixth month postoperatively. After evaluation of all groups, there was no difference in the microstructure of the surfaces but some differences in mechanical characteristics were apparent.