Outcomes of Primary Root Canal Therapy: An updated Systematic Review of Longitudinal Clinical Studies Published between 2003 and 2020

Background

A comprehensive effort to evaluate outcomes of primary root canal therapy (RCT) between 1966 and 2002 was published by Ng et al. (2007, International Endodontic Journal, 40, 921; 2008, International Endodontic Journal, 41, 6). Changes in endodontic materials and treatment methods warrant an updated analysis of outcomes.

Objectives

This study aimed to (1) quantify the success rates of primary RCT published between 2003 and 2020; and (2) investigate the influence of some characteristics known/suspected to be associated with treatment outcomes.

Methods

An electronic search was performed in the following databases (01‐01‐2003 to 12‐31‐2020): Pubmed, Embase, CINHAL, Cochrane and Web of Science. Included study designs were longitudinal clinical studies (randomized control trials, cohort studies, retrospective observational studies). Studies with at least twelve‐months of post‐operative review and success rates based on clinical and radiographic criteria were analysed. The terms ‘strict’ (complete resolution of periapical lesion) or ‘loose’ (reduction in size of existing periapical lesion) were used to describe the outcome criteria. Weighted, pooled success rates were calculated. Random effects meta‐regression models were used to investigate potential sources of statistical heterogeneity. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach was used to evaluate for quality assessment of the included studies.

Results

Forty‐two studies were included in the review. Meta‐analyses showed that the weighted pooled success rates were estimated to be 92.6% (95% CI: 90.5%–94.8%) under ‘loose criteria’ and 82.0% (95% CI: 79.3%–84.8%) under ‘strict’ criteria. The most significant areas of study heterogeneity were year of publication and qualification of operator. The majority (64.29%) of studies were considered to be of low quality of evidence.

Discussion

Biological factors continue to have the most significant impact on RCT outcomes. The technological method of instrumentation had no significant effect. The quality of evidence was based primarily on study design and only randomized control trials were considered to be ‘high’ quality of evidence.

Conclusions

The reported success rates show improvement over time. Weighted success rates for studies with a minimum of four‐years follow‐up had better outcomes, compared to those with less than four years, when ‘strict criteria’ were used.

Registration

PROSPERO database (CRD42021226311).

Clinical cell-based versus cell-free regenerative endodontics: clarification of concept and term

There is no consensus on the true meaning of clinical regenerative endodontics, and there is confusion over the concept and the term. Commonly used terms include revitalization and revascularization. The clinical methods for endodontic revitalization procedures and the tissue engineering concept differ depending on whether there is exogenous delivery of cells - called cell therapy, or not. Here, in this review, the difference is clarified by emphasizing the correct terminology: cell-free versus cell-based regenerative endodontic therapy (CF-RET versus CB-RET). The revitalization procedures practised clinically do not fit into the modern tissue engineering concepts of pulp regeneration but can be categorized as CF-RET. The modern tissue engineering concept in pulp regeneration is a CB-RET, which so far is at the clinical trial stage. However, histological examination of teeth following regenerative endodontic treatments reveals healing with repair derived from stem cells that originate from the periodontal, bone and other tissues. The aim of regenerative endodontics is regeneration of the pulp-dentine complex. This review discusses why CF-RET is unlikely to regenerate a pulp-dentine complex with current protocols. The American Association of Endodontists and the European Society of Endodontology have not yet recommended autologous stem cell transplantation (CB-RERT) which aspires for regeneration. Therefore, an understanding of the concept, term, difficulties and differences in current protocols is important for the clinician. However, rather than being discouraged that ideal regeneration has not been achieved to date, repair can be an acceptable outcome in clinical regenerative endodontics as it has also been accepted in medicine. Repair should also be considered in the context that resolution of the clinical signs/symptoms of pulp necrosis/apical periodontitis is generally reliably obtained in clinical regenerative endodontics.

Regenerative endodontics: a comprehensive review

The European Society of Endodontology and the American Association for Endodontists have released position statements and clinical considerations for regenerative endodontics. There is increasing literature on this field since the initial reports of Iwaya et al. (Dental Traumatology, 17, 2001, 185) and Banchs & Trope (Journal of Endodontics, 30, 2004, 196). Endogenous stem cells from an induced periapical bleeding and scaffolds using blood clot, platelet rich plasma or platelet-rich fibrin have been utilized in regenerative endodontics. This approach has been described as a 'paradigm shift' and considered the first treatment option for immature teeth with pulp necrosis. There are three treatment outcomes of regenerative endodontics; (i) resolution of clinical signs and symptoms; (ii) further root maturation; and (iii) return of neurogenesis. It is known that results are variable for these objectives, and true regeneration of the pulp/dentine complex is not achieved. Repair derived primarily from the periodontal and osseous tissues has been shown histologically. It is hoped that with the concept of tissue engineering, namely stem cells, scaffolds and signalling molecules, that true pulp regeneration is an achievable goal. This review discusses current knowledge as well as future directions for regenerative endodontics. Patient-centred outcomes such as tooth discolouration and possibly more appointments with the potential for adverse effects needs to be discussed with patients and parents. Based on the classification of Cvek (Endodontics and Dental Traumatology, 8, 1992, 45), it is proposed that regenerative endodontics should be considered for teeth with incomplete root formation although teeth with near or complete root formation may be more suited for conventional endodontic therapy or MTA barrier techniques. However, much is still not known about clinical and biological aspects of regenerative endodontics.

[International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: 3. Injuries in the primary dentition. Hebrew edition]

Traumatic injuries to the primary dentition present special problems and the management is often different as compared with the permanent dentition. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialities were included in the task group. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion or majority decision of the task group. Finally, the IADT board members were giving their opinion and approval. The primary goal of these guidelines is to delineate an approach for the immediate or urgent care for management of primary teeth injuries. The IADT cannot and does not guarantee favorable outcomes from strict adherence to the guidelines, but believe that their application can maximize the chances of a positive outcome. The Hebrew Edition is part of the IADT global effort to provide a worldwide accessibility to these guidelines. This third part will discuss injuries in the primary dentition.

[International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: 2. Avulsion of permanent teeth. Hebrew edition]

Avulsion of permanent teeth is one of the most serious dental injuries, and a prompt and correct emergency management is very important for the prognosis. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialties were included in the task group. The guidelines represent the current best evidence and practice based on literature research and professionals' opinion. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion or majority decision of the task group. Finally, the IADT board members were giving their opinion and approval. The primary goal of these guidelines is to delineate an approach for the immediate or urgent care of avulsed permanent teeth. The Hebrew Edition is part of the IADT global effort to provide a worldwide accessibility to these guidelines. This scond part of the guidelines will focus on avulsion of permanent teeth.

[International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: 1. Fractures and luxations of permanent teeth. Hebrew edition]

Traumatic dental injuries (TDIs) of permanent teeth occur frequently in children and young adults. Crown fractures and luxations are the most commonly occurring of all dental injuries. Proper diagnosis, treatment planning and follow up are important for improving a favorable outcome. Guidelines should assist dentists and patients in decision making and for providing the best care effectively and efficiently. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialties were included in the group. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion of the IADT board members. The guidelines represent the best current evidence based on literature search and professional opinion. The primary goal of these guidelines is to delineate an approach for the immediate or urgent care of TDIs. In this first article, the IADT Guidelines for management of fractures and luxations of permanent teeth will be presented. The Hebrew Edition is part of the IADT global effort to provide accessibility to these guidelines worldwide.

Band erosion after laparoscopic gastric banding: a retrospective analysis of 865 patients over 5 years

BACKGROUND

Gastric band erosion is a well-reported complication after laparoscopic adjustable gastric banding (LAGB). The published literature is limited and inconclusive with regard to its management. The authors therefore reviewed all band erosions detected during a 5-year period in a high-volume bariatric practice. Because a significant proportion of the band insertions (65%) were undertaken by an operator beyond his learning curve, the authors hoped to gain a mature, comprehensive understanding of this significant complication.

METHODS

The authors retrospectively reviewed the operative log of the operating theaters in their obesity surgery unit to find all the operations performed on LAGB patients for erosion from January 2003 to December 2007. The clinical notes and electronic records for each patient were reviewed. These data were cross-referenced against the authors' obesity surgery database, and denominator data such as the total number operations performed and demographics were found. Finally, postoperative outcomes were collated from the outpatient follow-up data and telephonic interviews, and the results were analyzed.

RESULTS

From January 2003 to December 2007, a single surgeon performed 865 LAGBs in the authors' unit. The authors identified 18 operations performed for LAGB erosions. The 18 patients (one referred from elsewhere, 14 women) formed the final study cohort (median preoperative body mass index [BMI], 46 kg/m(2)). Of the 17 erosions, 15 occurred relatively early in the series. The patients with the 213 Swedish adjustable gastric bands experienced 12 erosions (incidence, 5.6%) compared with 6 erosions with the 652 LAP-BANDs (incidence, 0.9%). The median time to presentation was 7 months (range, 1-60 months). However, 55% of the erosions (n = 10) occurred within the first year, and only 10% occurred after the second year. The most common presenting symptom was pain followed by weight regain. None of the patients experienced peritonitis. After surgical management of the erosion, three patients had a second LAGB and at this writing are well. Of the remaining patients, 11 are well, but 6 of these patients have returned to their previous weight (4 patients were lost to follow-up evaluation).

CONCLUSIONS

The overall incidence of LAGB erosions in our series was 1.96%. This incidence fell with increasing experience to 0.5% after the initial 300 bands were excluded from the analysis (3 band erosions in the last 565 band insertions). However, further increases in incidence are likely with a longer follow-up period. The most common presentation was abdominal pain followed by weight regain and port-site sepsis. In the authors' hands, laparoscopic omental plugging and band removal through a separate anterior gastrotomy appear to be effective methods for dealing with band erosions. Band erosion is a significant source of morbidity, with at least one-third of the erosion patients in our series not achieving their final goal of weight loss despite appropriate treatment. This study highlights the need for a future prospective randomized study to clarify the apparent strong influence of band design and construction on the etiopathogenesis of band erosion.

Variation of outcome in weight loss with band volume adjustments under clinical and radiological control following laparoscopic adjustable gastric banding

BACKGROUND

Following laparoscopic adjustable gastric banding (LAGB), patients usually undergo follow-up (FU) to optimize weight loss and detect complications, with band-volume adjustment performed either under radiological or clinical guidance with no current consensus on what is the best standard of care. We, therefore, analyzed our patient cohort to identify differences between the two, if any, over a 3-year period.

METHODS

We retrospectively reviewed our obesity surgery database to find all LAGB patients and grouped them based on method of FU without weight exclusions. We then selected out 70 consecutive patients from each cohort from an arbitrary time-point to achieve sufficient FU and analyzed the results from the data collated. Patients with postoperative complications were excluded to prevent bias.

RESULTS

From 2003 to 2007, there were 865 LAGB performed in our unit. We identified 70 consecutive patients from January 2004 from each cohort. After review and exclusions, we were left with 50 patients in the radiology group (RG) and 49 in the clinical group (CG) [median BMI 43.8 and 47.1, respectively; median age 43 years in both]. Routine FU was at weekly, then fortnightly, and monthly intervals, but results were analyzed at 3-month intervals until the first year and every 12 months until the third year. The median percentage of excessive weight loss was 22% and 36% at 6 months; 28% and 43% at 12 months; 27% and 47% at 2 years; and 33% and 46% at 3 years in the RG and CG, respectively. There was no difference in difficulties to band fill in either group as per clinical records, although there was a greater incidence of port damage in the CG.

CONCLUSIONS

Our study suggests that at medium-term follow-up, clinical fill is superior to radiological FU at least in terms of weight loss, with the added benefit of avoiding unnecessary radiation albeit that the difference between the two methods gets smaller with FU beyond 2 years. This topic merits a future randomized control trial to make recommendations without biases inherent to retrospective analysis.

Influence of psychological factors on risk of temporomandibular disorders

Psychological characteristics potentially may be a cause or consequence of temporomandibular disorder (TMD). We hypothesized that psychological characteristics associated with pain sensitivity would influence risk of first-onset TMD, but the effect could be attributed to variation in the gene encoding catechol-O-methyltransferase (COMT). We undertook a prospective cohort study of healthy female volunteers aged 18-34 yrs. At baseline, participants were genotyped, they completed psychological questionnaires, and underwent quantitative sensory testing to determine pain sensitivity. We followed 171 participants for up to three years, and 8.8% of them were diagnosed with first-onset TMD. Depression, perceived stress, and mood were associated with pain sensitivity and were predictive of 2- to 3-fold increases in risk of TMD (P < 0.05). However, the magnitude of increased TMD risk due to psychological factors remained unchanged after adjustment for the COMT haplotype. Psychological factors linked to pain sensitivity influenced TMD risk independently of the effects of the COMT haplotype on TMD risk.

Gastric bezoar complicating laparoscopic adjustable gastric banding with band slippage

Gastric bezoars may develop in the proximal pouch after gastric restriction, eg. by laparoscopic adjustable gastric banding (LAGB). To date, only two centers have reported this rare complication. We report an additional case with band slippage, to emphasize that bezoars should be considered in the differential diagnosis in patients presenting with new onset nausea and vomiting after LAGB.

Laparoscopic repair of large paraesophageal hiatus hernia: quality of life and durability

BACKGROUND

Laparoscopic repair of large paraesophageal hiatus hernias (LPOHH) is shown to be a safe and effective operation in the short term. However, its long-term durability and its effect on quality of life are less well established. This study aimed to assess the midterm outcome for laparoscopic repair of LPOHH with validated quality-of-life symptom scores and barium studies.

METHODS

Between January 2000 and July 2004, 49 patients (27 women) with LPOHH underwent laparoscopic repair. The median age of these patients was 68 years (range, 38-90 years). The laparoscopic repair included resection of the hernia sac, reduction of its contents, esophageal mobilization up to the aortic arch, crural repair with sutures (mesh reinforcement in 17 cases), Nissen fundoplication, and fixation of the wrap to the crura. Follow-up assessment was prospective with quality-of-life questionnaires, the Gastrointestinal Symptom Rating Scale (GSRS), the Gastroesophageal Reflux Disease-Health-Related Quality of Life (GERD-HRQOL) scale, and barium studies.

RESULTS

The presenting symptoms were pain for 21 patients, reflux for 27 patients, bleeding or anemia for 14 patients, and dysphagia for 17 patients. Five emergency operations were performed. Short esophagus was present in 24 patients. There were two conversions to open surgery. The major morbidity (atrial fibrillation, pulmonary embolism, and splenectomy) rate was 10.2%, and the minor morbidity (chest infection, jaundice, dysphagia, small pneumothorax) rate was 20.4%. Six patients were deceased of unrelated causes at the time of follow-up evaluation. Responses to the questionnaires were obtained in 31 cases (75%). Using the Wilcoxon signed rank test, the results from the questionnaires showed a statistically significant improvement (p < 0.001) in abdominal pain, reflux, and indigestion scores (GSRS) and GERD-HRQOL scores. Follow-up barium studies for 27 patients (66%) showed recurrence in 4 patients (14.8%), 2 of which were symptomatic.

CONCLUSION

Laparoscopic repair of LPOHH is associated with good quality of life as well as an acceptable midterm recurrence rate.

Healing of apical periodontitis after endodontic treatment: a comparison between a silicone-based and a zinc oxide-eugenol-based sealer

AIM

To assess the treatment results up to 1 year after endodontic treatment of apical periodontitis using a silicone-based sealer in comparison with Grossman's sealer, and to compare the results at 3 months after treatment with the 12-month follow-up to assess the prognostic value of a 3-month control.

METHODOLOGY

A total of 199 teeth were treated at three centres. The sealer was randomly chosen at the time of filling. Treatment results were evaluated clinically and radiographically 3 and 12 months after root-canal filling. The periapical status was evaluated using the periapical index (PAI).

RESULTS AND CONCLUSIONS

Average PAI scores decreased from 3.43 at start to 2.21 at 12 months for Grossman's sealer and from 3.40 to 2.26 for the silicon-based material. No significant difference between the groups at start or any of the follow ups was seen. The 3-month control was adequate in establishing significant healing in both groups. The improvement of the periapical condition continued at the 12-month examination.

The long term results of endoscopic surveillance of premalignant gastric lesions

BACKGROUND

A large proportion of patients attending open access endoscopy have histological and gross pathological findings that are potentially premalignant. The proportion of these patients who go on to develop malignancies and the timescale over which this occurs are uncertain.

AIMS

This study aims to discover the incidence of gastric cancers in this "high risk" group and to examine the potential for their early diagnosis and treatment.

PATIENTS

A total of 1753 patients attended open access endoscopy. From these, 166 patients with dysplasia, intestinal metaplasia, atrophic gastritis, foveolar hyperplasia, regenerative changes, polyps, or ulcers who agreed to undergo annual surveillance endoscopy were studied.

METHODS

Patients were endoscoped annually. Additionally, patients with ulcers were re-examined at two monthly intervals until ulcer healing. Cancers detected were treated by gastrectomy.

RESULTS

Twenty two of 1753 patients attending open access endoscopy had gastric cancer (1.3%). In the study population, 14 cancers were detected over 10 years (8.4 %). These were of an earlier stage than those detected at open access (stage I and II 67% v 23%; p<0.05) and five year survival was significantly higher (50% v 10%; p=0.006). In atrophic gastritis and intestinal metaplasia the risk of malignancy was 11%.

CONCLUSIONS

In patients with atrophic gastritis or intestinal metaplasia, annual surveillance can detect most new tumours at an early stage with a major improvement in survival. Potential benefits of such a surveillance programme are large and warrant further investigation in a multicentre randomised controlled trial.

Laser Doppler flowmetry for monitoring traumatized teeth

Laser Doppler Flowmetry (LDF) has been shown to be valuable in monitoring revascularization of immature incisors following severe dental trauma. Several investigators have demonstrated the ability of LDF to record blood flow signals from vital tooth pulps. In this case report, LDF was used for a 7-year-old child patient following a severe luxation of tooth #9. During follow-up examinations the traumatized tooth was unresponsive to traditional vitality testing during the first 6 months; however, LDF indicated that revascularization had occurred much sooner. Until recently, CO2 ice has been the most effective method for sensitivity testing in trauma cases such as presented here. In this case, LDF gave us the assurance that we could defer invasive care during a critical time period when root canal therapy might have been initiated for this child patient.

Bacteria isolated after unsuccessful endodontic treatment in a North American population

OBJECTIVE

The purpose of this study was to determine the composition of the microbial flora present in teeth after the failure of root canal therapy in a North American population. These results were then compared with those of the previous Scandinavian studies.

STUDY DESIGN

Fifty-four root-filled teeth with persistent periapical radiolucencies were selected for retreatment. After removal of the root-filling material, the canals were sampled with paper points, and by reaming of the apical dentin. Both samples were grown under aerobic and strict anaerobic conditions. Then the bacterial growth was analyzed.

RESULTS

The microbial flora was mainly of 1 to 2 strains of predominantly gram-positive organisms. Enterococcus faecalis was the most commonly recovered bacterial species.

CONCLUSIONS

Bacteria were cultivated in 34 of the 54 teeth examined in the study. E faecalis was identified in 30% of the teeth with a positive culture.

Efficacy of laser Doppler flowmetry for the diagnosis of revascularization of reimplanted immature dog teeth

This study was performed to assess if laser Doppler flowmetry (LDF) is an improved method for the detection of revascularization of replanted teeth. Teeth were extracted and reimplanted under different experimental conditions. LDF readings were taken before extraction and weekly for 3 months. In control teeth, LDF baseline readings were taken and then repeated after the apical blood vessels were cut surgically. At the end of 3 months it was determined radiographically and histologically whether revascularization had occurred, i.e. vitality had returned.

RESULTS

LDF readings correctly predicted the pulp status (vital vs. non-vital) in 83.7% of the readings. 73.9% (17 of 23) were correct for the vital teeth and 95% (19 of 20) were correct for the non-vital teeth. Fisher's exact test (2-tail) indicated that there was no significant association between the efficacy of LDF and tooth type (P = 0.166), although P2 was the least accurate tooth tested. Wilcoxon's matched-pair signed rank test demonstrated that in the revascularized (vital) teeth, the flux value between the baseline and week 2 dropped significantly (P = 0.0001), increased significantly from week 2 to week 4 (P = 0.0001) and then decreased steadily until week 12. However, at week 12 the flux was still significantly higher than at week 2 (P = 0.010). In the teeth that failed to revascularize, the flux value dropped significantly by weeks 1 and 2 (P = 0.004 and P = 0.0001, respectively). Flux values did not increase from week 2. A Fast Fourier Transform (FFT) analysis confirmed a pulse of dominant frequency of 2 Hz in the teeth that returned to vitality and the lack thereof in those that stayed non-vital. One tooth in which the flux value evaluation indicated a non-vital tooth but the radiographic/histologic findings showed vital (false negative) possessed a pulse of dominant frequency and proved by this method to have successfully revascularized.

Local Vibrotactile and Pain Sensitivities Are Negatively Related in Temporomandibular Disorders

Earlier research has shown that cutaneous experimental pain can elevate the vibrotactile threshold at the same skin locus. The purpose of this study was to determine whether vibrotactile and pain thresholds in a clinical (temporomandibular disorders [TMD]) population are consistent with the hypothesis that chronic pain causes a similar elevation. Specifically, we predicted that TMD subjects with soreness (low palpation-pain threshold) at a given skin site would have relatively high vibrotactile thresholds at the same location. Measurements on the skin overlying the masseter in 18 individuals with TMD showed that pain sensitivity was negatively correlated with sensitivity to 20-Hz vibration (presumed to activate a rapidly adapting mechanoreceptive channel), but not with sensitivity to 200-Hz vibration (thought to activate primarily a slowly adapting channel, because the Pacinian channel is lacking in the orofacial region). There was no relationship between vibration thresholds over the masseter and pain threshold at other orofacial sites, including the contralateral masseter. Vibrotactile and pain thresholds were uncorrelated in control participants without chronic pain (n = 18). The results indicate that in TMD, a localized relationship exists between pain sensitivity and the sensitivity of a low-frequency vibrotactile channel.

Early neurohormonal effects of trandolapril in patients with left ventricular dysfunction and a recent acute myocardial infarction: a double-blind, randomized, placebo-controlled multicentre study

Angiotensin-converting enzyme inhibitors improve long-term survival in patients with left ventricular dysfunction after a myocardial infarction, but their mechanism of action is not entirely clear. The neurohormonal effects may be important in this respect, as well as an early hemodynamic unloading induced by these drugs. The primary objective was to assess the effect of trandolapril on plasma levels of atrial natriuretic peptide. A secondary objective was to assess the effects of trandolapril on selected neurohormones, vasoactive peptides and enzymes, which may be important in the development of left ventricular remodeling and heart failure following an acute myocardial infarction. A total of 119 patients with an acute myocardial infarction and a wall motion index < or =1.2 (16-segment echocardiographic model) were randomized to double blind treatment with trandolapril or placebo within 3-7 days after the onset of infarction. Blind treatment was discontinued 21 days after the index infarction. Venous blood samples were collected at rest, before randomization and on the day after treatment was discontinued. At the end of the study, there were no differences in plasma levels of atrial natriuretic peptide between the two treatment groups. Angiotensin-converting enzyme activity was suppressed and plasma renin activity was higher in the trandolapril group. No differences in plasma levels of N-terminal pro-atrial natriuretic peptide, brain natriuretic peptide, aldosterone, noradrenaline, adrenaline, vasopressin, big endothelin-1 and neuropeptide Y were found between the two treatment groups. There were positive correlations between several markers of neurohormonal activation at baseline and variables expressing left ventricular dysfunction and clinical heart failure. Neurohormonal activation is related to left ventricular dysfunction. The effects of 2-3 weeks of angiotensin-converting enzyme inhibition on neurohormonal activation does not predict the already established beneficial long-term effects after myocardial infarction. Thus, early modulation of circulatory neurohormone levels may not be a major mechanism for the efficacy of angiotensin-converting enzyme inhibitors in these patients. Selected plasma hormone markers may still be used to identify patients who might get the greatest benefit from treatment.

Reduction of intracanal bacteria using nickel-titanium rotary instrumentation and various medications

The purpose of this study was to evaluate the extent of bacterial reduction with nickel-titanium rotary instrumentation and 1.25% NaOCl irrigation. Also, the additional antibacterial effect of calcium hydroxide for >1 wk was tested. Forty-two subjects with radiographic and clinical signs of chronic apical periodontitis were recruited. The canals were sampled before treatment, during and after instrumentation, and after treatment with calcium hydroxide and the samples incubated anaerobically for 7 days at 37 degrees C. The bacteria from each sample were quantified and the log10 values were used for calculations and comparisons. The initial sample confirmed infection of the canals. There was a significantly greater pattern of reduction of bacteria when NaOCl was used as an irrigant, compared with sterile saline (p < 0.05). After instrumentation with NaOCl irrigation, 61.9% of canals were rendered bacteria-free. The placement of calcium hydroxide for at least 1 wk rendered 92.5% of the canals bacteria free. This was a significant reduction, compared with NaOCl irrigation alone (p = 0.0001). The results of this study indicate that NaOCl irrigation with rotary instrumentation is an important step in the reduction of canal bacteria during endodontic treatment. However this method could not consistently render canals bacteria-free. The addition of calcium hydroxide intracanal medication should be used to more predictably attain this goal.

Population studies and validation of paternity determinations by six microsatellite loci

A single locus system of 6 microsatellite markers was evaluated for paternity testing. A nonradioactive method based on peroxidase labeling of a DNA probe was used to estimate the allele frequency of markers D1S216, D3S1217, D7S480, D9S157, D13S153, and D16S422 by genotyping 1134-1698 chromosomes. The number of detected alleles were 22, 15, 23, 10, 16, and 19, respectively, and the allele frequency varied from 0.001 to 0.317. The genotype of 87 families, consisting of mother, father, and child was determined. The probability that a random individual will give a positive paternity was evaluated. We conclude that the markers can be reliably typed and give sufficient and reliable information for paternity testing.

Radiographic evaluation of periapical healing after obturation of infected root canals: an in vivo study

AIM

To radiographically compare periapical repair of roots with infected root canals obturated in one-step or with calcium hydroxide (Ca(OH)2) intracanal medication in two steps.

METHODOLOGY

Standardized preoperative periapical radiographs were taken of 72 roots of vital dogs' teeth. All roots were then aseptically instrumented to ISO size 45. As negative controls, 12 roots were aseptically obturated. The remaining roots were infected with dental plaque and closed. Six weeks later, apical periodontitis was radiographically confirmed in the infected roots. The roots were divided into the following groups: group 1, one-step (n = 24); roots were irrigated with 10 cc saline, obturated, and permanently restored. Group 2, Ca(OH)2 (n = 24); roots were treated as in group 1, except that after saline irrigation Ca(OH)2 medicament was placed in the canal 1 week before obturation. Group 3, positive control (n = 12); the roots were irrigated with saline, access permanently closed but canals not obturated. Group 4, negative control (n = 12); previously aseptically obturated roots were permanently restored. After 6 months, standardized postoperative radiographs were obtained. Three independent evaluators blinded to the treatment groups evaluated the preoperative and postoperative radiographs. The evaluators were instructed to rate each root, based on changes on the radiographs, as failed, improved or healed.

RESULTS

Radiographically, the percentage of cases that completely healed were similar for the one-step and Ca(OH)2 groups (35.3% vs. 36.8%). However, the Ca(OH)2 group had fewer failed cases (15.8% vs. 41.2%) and more improved cases (47.4% vs. 23.5%) than the one-step group.

CONCLUSION

Power statistics demonstrated that at 43 cases per group, Ca(OH)2 treatment would be statistically superior to one-step treatment. We consider this number to be clinically important.

Effects of gender and acute dental pain on thermal pain responses

OBJECTIVE

Considerable research suggests that females exhibit greater sensitivity to laboratory pain procedures than do males; however, whether the presence of acute clinical pain influences this sex difference in pain sensitivity has not been investigated. The present experiment investigated the effects of sex and acute dental pain on laboratory pain responses.

DESIGN

Thermal pain onset and tolerance were determined in 46 dental patients (15 male, 31 female) experiencing pain due to acute irreversible pulpitis and in 33 healthy controls (13 male, 20 female). In addition, measures of mood and coping were obtained in all participants. All subjects participated in two experimental sessions. The first session took place immediately before the patients underwent endodontic treatment for relief of pulpal pain. The second session took place approximately 1-2 weeks later, when pulpitis patients were pain free after treatment. During each session, thermal pain onset and tolerance were assessed with a 1-cm2 contact thermode applied to the right volar forearm using an ascending method of limits.

RESULTS

During both sessions, thermal pain onset and tolerance were lower in control females than in control males; however, male and female pulpitis patients did not differ in their thermal pain responses during either session. Pulpitis patients also showed greater affective distress than controls.

CONCLUSIONS

These data suggest that the sex difference in thermal pain sensitivity frequently reported in pain-free subjects appears to be absent in patients presenting with acute dental pain. However, this effect cannot be explained solely based on the presence of clinical pain because the effect on pain threshold and tolerance persisted into session 2, when pulpitis patients were pain free. Potential explanations for these results are discussed.

A gene for lymphedema-distichiasis maps to 16q24.3

Lymphedema-distichiasis (LD) is a dominantly inherited syndrome with onset of lymphedema at or just after puberty. Most affected individuals have distichiasis-fine hairs arising inappropriately from the eyelid meibomian glands-which is evident from birth. A study of three families with LD has shown linkage to chromosome 16q24.3, and subsequent analysis of the region for recombinant genes places the locus between D16S422 and D16S3074, a distance of approximately 16 cM. Possible candidate genes in this interval include the N-proteinase for type 3 collagen, PCOLN3; the metalloprotease PRSM1; and the cell matrix-adhesion regulator, CMAR.

The gene for cherubism maps to chromosome 4p16.3

Cherubism is a rare familial disease of childhood characterized by proliferative lesions within the mandible and maxilla that lead to prominence of the lower face and an appearance reminiscent of the cherubs portrayed in Renaissance art. Resolution of these bony abnormalities is often observed after puberty. Many cases are inherited in an autosomal dominant fashion, although several cases without a family history have been reported. Using two families with clinically, radiologically, and/or histologically proved cherubism, we have performed a genomewide linkage search and have localized the gene to chromosome 4p16.3, with a maximum multipoint LOD score of 5. 64. Both families showed evidence of linkage to this locus. Critical meiotic recombinants place the gene in a 3-cM interval between D4S127 and 4p-telomere. Within this region a strong candidate is the gene for fibroblast growth factor receptor 3 (FGFR3); mutations in this gene have been implicated in a diverse set of disorders of bone development.

Sexual and physical abuse history in subjects with temporomandibular disorders: relationship to clinical variables, pain sensitivity, and psychologic factors

Recent evidence suggests that a past history of physical and/or sexual abuse is more frequently reported among chronic pain populations; however, the prevalence of reported abuse has not been examined in patients with chronic orofacial pain caused by temporomandibular disorders (TMD). This study compares reported physical/sexual abuse among female TMD subjects recruited from the general population with that of age-matched female control subjects. The association of reported abuse with clinical pain, experimental pain responses, and psychologic variables was examined in the TMD group. Results indicated that a slightly but not statistically greater percentage of TMD subjects (44.8%) reported a history of sexual or physical abuse compared to control subjects (33.3%). Reported abuse among TMD subjects was not related to clinical pain or psychologic variables. Regarding experimental pain responses, TMD subjects reporting a history of abuse exhibited longer ischemic pain tolerances compared to those not reporting abuse; however, the groups did not differ on other experimental pain measures. Results indicate that the reported prevalence of physical/sexual abuse is similar among TMD subjects compared to other chronic pain populations; however, the relationship of abuse to clinical and psychosocial variables remains unclear.

High incidence of loss of heterozygosity in breast tumors from carriers of the BRCA2 999del5 mutation

Germ-line mutation in the BRCA2 gene confers an increased risk of breast cancer. An elevation of additional genetic defects in tumors of patients with germ-line mutation in the BRCA2 gene compared with sporadic breast tumors has been reported. To evaluate the nature of the difference, we did detailed mapping of chromosomes 1p, 3p, 6q, 11, 13q, 16q, 17, and 20q, using microsatellite markers. We found that the frequency of loss of heterozygosity was similar at some chromosomal regions in the BRCA2 999del5 and sporadic tumors but significantly different at others. These others include chromosomal arms 3p, 6q, 11p, 11q, 13q, and 17p. Loss of heterozygosity mapping suggests that the same chromosome regions are involved in both tumor groups but at elevated frequencies in BRCA2 999del5 tumors. This higher frequency of genetic aberrations could pinpoint genes that selectively promote tumor progression in individuals predisposed to breast cancer due to the BRCA2 999del5 germ-line mutation. Accumulation of somatic genetic changes during tumor progression may follow a specific and more aggressive pathway of chromosome damage in these individuals.

Sensitivity of patients with painful temporomandibular disorders to experimentally evoked pain: evidence for altered temporal summation of pain

Temporomandibular disorders (TMD) represent a group of chronic painful conditions involving the muscles of mastication and the temporomandibular joint. Several studies have reported that TMD is associated with enhanced sensitivity to experimental pain. Twenty-three TMD subjects and 24 pain-free matched control subjects participated in a set of studies which were designed to evaluate whether the temporal integrative aspects of thermal pain perception are altered in TMD patients compared with control subjects. Specifically, we have examined in both TMD patients and in age- and gender-matched control subjects: (1) the time-course and magnitude of perceived pain evoked by the application of sustained 7-s noxious thermal stimuli (45-48 degrees C) to the face and forearm, (2) the central summation of C-fiber-mediated pain produced by applying brief trains of noxious heat pulses to the skin overlying the ventral aspect of the right palm and (3) the ability to discriminate small increments in noxious heat applied to facial and volar forearm skin. Data collected from these studies indicate that TMD patients show enhanced temporal integration of thermal pain compared with control subjects. TMD patients show greater thermal C-fiber-mediated temporal summation than pain-free subjects and they report a greater magnitude of sustained noxious heat pulses applied to either the face or the forearm than control subjects. In contrast to these findings, TMD and pain-free subjects are equally able to discriminate and detect small increments of heat applied to noxious adapting temperatures. These findings suggest that the augmented temporal integration of noxious stimuli may result from alterations in central nervous system processes which contribute to the enhanced pain sensitivity observed in TMD patients.

High frequency of LOH at chromosome 18q in human breast cancer: association with high S-phase fraction and low progesterone receptor content

Human primary breast cancers were analysed for somatic loss of heterozygosity (LOH) at chromosome 18 with 15 polymorphic microsatellite markers. LOH was observed in 148 of the 228 cases analyzed, (65%). Three smallest common deletion regions (SCDR) were detected on the long arm of chromosome 18. The marker D18S51 at the region 18q22 showed the highest LOH (42%). Tumors with and without LOH at 18q were tested for association with clinico-pathological features of the tumors, such as estrogen and progesterone receptor content, age at diagnosis, tumor size, node status, histological type, S-phase fraction, DNA ploidy and LOH at other chromosomal regions. A significant association was found between LOH at 18q and high S-phase fraction (99.9% confidence interval) and low progesterone receptor content (99% confidence interval). Furthermore, an association was found between LOH at 18q and LOH at 1p, 7q, 9p, 13q and 17q. We conclude that there are three separate LOH target regions at chromosome 18q, and that inactivation of one or more genes at these regions might be important for human breast carcinogenesis.

Relationship between pain sensitivity and resting arterial blood pressure in patients with painful temporomandibular disorders

OBJECTIVE

Patients experiencing temporomandibular disorders (TMD) show greater sensitivity to painful stimuli than age- and gender-matched control subjects. This enhanced pain sensitivity may result, at least in part, from an alteration in pain regulatory systems that are influenced by resting arterial blood pressure. In this study, we examined the relationship between resting systolic blood pressure and pain perception in 64 female TMD and 23 age-matched pain-free female subjects.

METHOD

Resting arterial blood pressure and measures of thermal and ischemic pain threshold and tolerance were determined for each participant. Subjective ratings of thermal pain evoked by suprathreshold noxious thermal stimuli (45-49 degrees C) using a magnitude matching procedure were also obtained for both groups.

RESULTS

TMD patients had lower thermal and ischemic pain thresholds and tolerances than pain-free subjects (ps < .05). Both groups provided equivalent intensity ratings to suprathreshold noxious thermal stimuli. A median split of each group based on resting systolic blood pressure revealed an influence of blood pressure on both thermal and ischemic pain perception for the Pain-Free group. The Pain-Free high resting blood pressure subgroup had higher thermal pain tolerances, higher ischemic pain thresholds, and provided lower magnitude estimates of the intensity of graded heat pulses compared with the Pain-Free low blood pressure subgroup. A trend toward a significant effect of blood pressure level on ischemic pain tolerance was also observed for the Pain-Free group. In contrast to the Pain-Free group, blood pressure level did not influence ischemic or thermal pain perception for TMD patients. Similar to the lack of effect of resting blood pressure on experimental pain perception in TMD patients, resting blood pressure was not related to measures of clinical orofacial pain in TMD patients.

CONCLUSIONS

These findings confirm our previous findings that TMD patients are more sensitive to noxious stimuli and suggest that painful TMD may result, at least in part, from an impairment in central pain regulatory systems that are influenced by resting arterial blood pressure.

In vitro susceptibility of Helicobacter pylori to protolichesterinic acid from the lichen Cetraria islandica

With reference to the traditional use of Cetraria islandica (Iceland moss) for relief of gastric and duodenal ulcer, plant extracts were screened for in vitro activity against Helicobacter pylori. (+)-Protolichesterinic acid, an aliphatic alpha-methylene-gamma-lactone, was identified as an active component. The MIC range of protolichesterinic acid, in free as well as salt form, was 16 to 64 micrograms/ml.

Loss of heterozygosity at chromosome 7q in human breast cancer: association with clinical variables

In this study 238 human primary breast cancers were analysed with 9 polymorphic microsatellite markers specific to region 7q21-q35 on chromosome 7. LOH was observed at one or more marker in 82 cases or (34%). The deletions were evenly distributed throughout the region. Patients were divided into two groups according to whether LOH was observed in their tumours or not, and tested for association with overall survival, the clinicopathological features: steroid receptor content, tumour size, node status, DNA ploidy and S-phase fraction, and LOH at other chromosomal regions. An association was found between 7q LOH and high S-phase fraction. An association was found between LOH at 7q and LOH at 1p, 3p, 9p, 13q and 17q. These results suggest the location of a putative tumour suppressor gene at chromosome 7q21-q35 that, in combination with other deletions, might enhance tumour growth.

Pain sensitivity in patients with temporomandibular disorders: relationship to clinical and psychosocial factors

OBJECTIVE

We have previously reported that patients with temporomandibular disorders (TMD) exhibit enhanced sensitivity to experimentally evoked pain (1); however, the clinical relevance of this increased pain sensitivity remains unclear. The purpose of this study was to investigate the relationship of experimental pain sensitivity to clinical and psychosocial variables among patients with TMD.

DESIGN

Thirty-six TMD patients were studied, half of whom were pain sensitive (PS) and the other half pain tolerant (PT), based on their ability to tolerate an ischemic pain task. Responses to painful thermal and nonpainful visual stimuli as well as clinical/diagnostic symptoms and psychosocial variables were compared for the two groups (i.e., PS vs. PT).

RESULTS

Results indicated that, compared with PT patients, the PS group exhibited greater sensitivity to thermal pain and rated innocuous visual stimuli as more intense. PS patients also reported greater clinical pain, but in general the groups did not differ on diagnostic and psychosocial measures.

CONCLUSIONS

The results suggest that ischemic pain tolerance is a clinically relevant marker of pain sensitivity in TMD patients. These findings are consistent with the hypothesis that impairments in CNS inhibitory pathways may contribute to the pain associated with TMD.

The role of neurohormonal activation in chronic heart failure and postmyocardial infarction

Chronic heart failure is a disabling and lethal disorder with high incidence and prevalence in Western societies. Treatment with angiotensin-converting enzyme (ACE) inhibitors and heart transplantations diminish both mortality and morbidity, although both still remain high. Increased understanding of some of the pathophysiologic mechanisms involved in the development of left ventricular dysfunction and the transition from asymptomatic systolic dysfunction to symptomatic heart failure has opened gates to new dimensions for the treatment of this disorder. The initial event in the pathophysiologic process is damage to the myocardium, most frequently a myocardial infarction. Almost simultaneously, activation of different neurohormonal systems occurs. The renin-angiotensin system and sympathetic nervous system are activated. Increased concentrations of hormones with counteractive activity have also been found, such as ANP and BNP. Interestingly, prolonged neurohormonal activation seems to occur only in patients with large infarcts or in patients with poor systolic function of the left ventricle. Moreover, available data from an echocardiographic study indicates that in patients with high concentrations of neurohormones in plasma a week after their infarction, left ventricular dilatation and systolic dysfunction of the left ventricle are highly likely to develop during long-term follow-up. Several studies have showed that ACE inhibitors are efficacious in chronic heart failure and among patients with reduced ejection fraction after myocardial infarction. What these patients have in common is prolonged neurohormonal activation, which theoretically may be harmful to myocardial cell structure and function. ACE inhibitors reduce the breakdown of angiotensin I to angiotensin II and increase the concentration of circulating bradykinins and prostaglandins. Further modulation of neurohormonal activity might be beneficial. Therefore, future treatment of chronic heart failure or asymptomatic left ventricular dysfunction might include beta-adrenergic blockers, neutral endopeptidase inhibitors, ANP, BNP, angiotensin II receptor antagonists, and modulators of sympathetic activity.

Application of contemporary methods for the use of international data in national genetic evaluations

Increased international trade of genetic material from dairy cattle requires genetic evaluations across countries. Methods are discussed for comparing genetic evaluations of bulls computed in different countries. A system that combines information from several countries and produces routine international evaluations of dairy bulls is described, and possible ways of utilizing such international information in national breeding programs are presented. Important issues for international genetic evaluations are the estimation of genetic parameters within and across countries and the impact of imported bull evaluations on international rankings. Both issues are discussed in this article in view of recent research findings and potential future applications. Optimally, routine systems for international evaluation of the future will consider all economically important traits and serve different and well-defined breeding goals.