Recreational cannabis consumption: a public health perspective

Introduction

The misuse of psychoactive drugs is an important public health problem. It's estimated that there are between 120-224 million users worldwide. In 2001, Portugal started the legal process to decriminalize the use of narcotic drugs and psychotropic substances.

Objectives

To analyze the recreational use of cannabis from a Public Health perspective, to summarize the adverse health effects, to describe the situation in countries where it's legal, and to assess the impacts of its legalization.

Methods

A literature review was carried out using the main databases of scientific articles. Additionally, legal documentation, institutional reports, journalistic pieces, interviews and books were also consulted.

Results

Individual possible effects of punctual used found were: Temporary feeling of euphoria and relaxation; Distortion of perception; Changes in short-term memory and concentration; Altered motor coordination; Paranoia and psychosis. Effects of regular consumption or products with a high THC content: Dependency; Changes in brain development; Cognitive impairment; Decreased life satisfaction and personal fulfilment; Depression. Population level effects described were: increased number of consumers, increased risk of dangerous driving and accidents; decreased suicide rate and death from opioid overdose, decline in black market and in criminality near trading posts. The legalization of consumption in certain countries has allowed us to realize that the price, the quantity of product and the definition of sales locations are relevant topics for the successful implementation of policies in this area.

Conclusions

As the cannabis legalization policy is changed, it is expected the consumption will increase. An investment in prevention campaigns and increase in health literacy should begin before this change focusing particularly on younger people and drivers. This way, the negative health and social effect that can arise from this change will be minimized.

Key messages

Campaigns to prevent cannabis use must begin before legalization. Campaigns to prevent cannabis use should target teenagers and young people and drivers.

Impact of cesarean section in a private health service in Brazil: indications and neonatal morbidity and mortality rates

OBJECTIVE

To evaluate the incidence of, indications of, and maternal and neonatal morbidity and mortality rates in cesarean sections in a private health service in Brazil.

DESIGN

Retrospective and observational study.

SETTING

Private health service in Vitória, Espírito Santo, Brazil.

METHODS

The patients were interviewed using a structured questionnaire to determine maternal age, gestational age at the time of delivery, number of previous deliveries, type of delivery performed, duration of labor, indications for cesarean delivery, point at which cesarean section was performed, physician responsible for delivery, and maternal morbidity, fetal morbidity, and fetal mortality rates. A descriptive analysis of the data was conducted. Students t-test was performed to compare quantitative variables, and Fishers exact test was performed for categorical variables.

RESULTS

A total of 584 patients were evaluated. Of these, 91.8% (536/584) had cesarean sections, while only 8.2% (48/584) had vaginal deliveries. There were no reports of forceps-assisted vaginal deliveries. In 87.49% of the deliveries, the number of gestational weeks was more than 37. In terms of indications for performing cesarean section, 48.5% were for maternal causes, 30.41% were for fetal causes, and 17.17% were elective. Maternal re-hospitalization due to puerperal complications was necessary in 10.42% of the vaginal deliveries and in 0.93% of the cesarean deliveries (p<0.001). Complications were observed in 18.75% of the vaginally delivered newborns and in 17.16% of those delivered by cesarean section. Of the newborns with complications at birth, 40.59% (41/101) had to be admitted to the neonatal intensive care unit. There were no cases of maternal death. There were seven cases of fetal/neonatal death.

CONCLUSION

We observed that the vast majority of deliveries in the private sector are performed by cesarean section, without labor, and by the patients obstetrician. We found no serious maternal complications or increased neonatal morbidity rates associated with cesarean section.

Evaluation of estimated genetic values and their application to genome-wide investigation of systolic blood pressure

The concept of breeding values, an individual's phenotypic deviation from the population mean as a result of the sum of the average effects of the genes they carry, is of great importance in livestock, aquaculture, and cash crop industries where emphasis is placed on an individual's potential to pass desirable phenotypes on to the next generation. As breeding or genetic values (as referred to here) cannot be measured directly, estimated genetic values (EGVs) are based on an individual's own phenotype, phenotype information from relatives, and, increasingly, genetic data. Because EGVs represent additive genetic variation, calculating EGVs in an extended human pedigree is expected to provide a more refined phenotype for genetic analyses. To test the utility of EGVs in genome-wide association, EGVs were calculated for 847 members of 20 extended Mexican American families based on 100 replicates of simulated systolic blood pressure. Calculations were performed in GAUSS to solve a variation on the standard Best Linear Unbiased Predictor (BLUP) mixed model equation with age, sex, and the first 3 principal components of sample-wide genetic variability as fixed effects and the EGV as a random effect distributed around the relationship matrix. Three methods of calculating kinship were considered: expected kinship from pedigree relationships, empirical kinship from common variants, and empirical kinship from both rare and common variants. Genome-wide association analysis was conducted on simulated phenotypes and EGVs using the additive measured genotype approach in the SOLAR software package. The EGV-based approach showed only minimal improvement in power to detect causative loci.

Bacterial productivity distribution during a rainy year in an estuarine system

Bacterial density and productivity were investigated along four salinity gradients within the estuary Ria de Aveiro. Bacterial variables and environmental parameters were measured at three to four stations spanning the entire salinity gradient of the four channels. The rather high variation in bacterial productivity (0.16-7.6 microg C L(-1) h(-1)) along the profiles of salinity indicates that bacterial activity shows a reactive behavior to environmental changing. Bacterial density (0.5-11.2 x 10(9) cells L(-1)) with a comparative smaller variation showed a more conservative behavior, mainly reflecting the phytoplankton distribution. Contrary to expectation, minimal values of bacterial productivity were not observed in November-December but in June. In fact, in November-December, the deep zone near the mouth showed the highest values of bacterial activity. At the upper stations, the highest values were observed in October. The relatively high values of bacterial production during the cold rainy season suggest that allochthonous substrates leached out from the surroundings by rain controlled the distribution of bacterial activity in the estuarine system. The substantial decrease in salinity during the rainy season negatively affected bacterial productivity, namely in the marine zone, where water column was highly stratified. Salinity seems to play an indirect role in the regulation of estuarine bacteria because there are different bacterial communities adapted to a wide salinity range.

Activity and growth efficiency of heterotrophic bacteria in a salt marsh (Ria de Aveiro, Portugal)

Bacterial utilization of monomers is recognized as an important step in the biogeochemical cycling of organic matter. In this study we have compared the heterotrophic activity of bacterial communities from different micro-habitats within a salt marsh environment (Ria de Aveiro, Portugal) in order to establish spatial patterns of bacterial abundance, monomer turnover rates (Tr) and bacterial growth efficiency (BGE). Differences in bacterial abundance and activity could be found between distinct plant rhizospheres. BGE tended to be lower at Halimione portulacoides banks, when compared to Sarcocornia perennis subsp. perennis banks which, on the contrary, showed the highest bacterial densities. Experiments of amendment of natural samples with organic and inorganic supplements indicated that salt marsh bacteria are not strongly regulated by salinity but the increased availability of labile organic matter causes a significant metabolic shift towards mineralization.

Relationship of bacterioplankton production with primary production and respiration in a shallow estuarine system (Ria de Aveiro, NW Portugal)

The response of bacterial growth to phytoplankton production and planktonic respiration (RESP) variation was examined over different stations and dates in the shallow estuarine system Ria de Aveiro. The temporal and spatial profiles of bacterial productivity (2.7-744.2mg Cm(-3)d(-1)) did not coincide with those of primary production (PP) (0.2-19.1 g Cm(-3)d(-1)) and RESP (0.1-8.2 g Cm(-3) d(-1)). The bacterioplankton production/PP ratio varied differently, depending on the season and location. The heterotrophic zones, with the lowest values of PP, exhibited the most intense bacterial secondary production. Moreover, the variation of PP in the system was rather small when compared with that of bacterial secondary production. These suggest that, in a large extension of the lagoon and throughout the year, bacterioplankton growth is largely dependent on non-phytoplanktonic carbon sources. Benthic PP and/or allochtonous organic matter from land have a fundamental role in the dynamics of the planktonic compartment of the estuarine system.

A clinical study of glass ionomer cement

The aim of this investigation was to compare the clinical performance of a glass ionomer cement (GIC) with a composite resin when used for direct bonding of standard edgewise orthodontic brackets. Fourteen patients (10 females, four males), in whom 242 teeth were bonded with brackets, were divided into two groups: GIC (121 teeth) and composite (121 teeth). The brackets were allocated to alternate quadrants and first-time failures were recorded over a period of 24 months. Data were analysed statistically (non-parametric chi-squared test). The results demonstrated a significantly lower unpreviewed debonding index (UDI) (15.7 per cent) for the composite than for the GIC (28.1 per cent) (P = 0.042). The use of heavy archwires was largely responsible for this difference. No difference was observed when light and medium archwires were used. GIC may be a viable alternative to composite for use with light archwires and with limited treatment objectives.

Isolation of Neospora caninum from the brain of a naturally infected dog, and production of encysted bradyzoites in gerbils

Neospora caninum was isolated from the brain of an adult dog in Brazil. Cerebral tissue from the dog was inoculated into Mongolian gerbils. Gerbils were euthanized 3-4 months later and bradyzoite-containing tissue cysts were observed in their brains. N. caninum (designated NC-Bahia) was isolated in cell culture after inoculation with tissue cysts from the gerbils. The identity of the parasite was confirmed by immunohistochemical examination and polymerase chain reaction (PCR). Gerbils may be a useful alternative to immunosuppressed mice for isolation of N. caninum and for production of encysted bradyzoites.

Orthodontics around the world: orthodontics in Brazil: excellence for a minority

Brazil is the largest country of South America, with an area of 8.511.965 km(2) and 150 million people. It has 113 dental schools and several orthodontic postgraduate courses variously at Certificate, Master, and Doctoral levels. The current article gives an overview of the speciality in Brazil. The discussion puts the delivery of orthodontic care within the context of social conditions in Brazil. Included is a description of two full-time orthodontic courses located in the city of Rio de Janeiro.

[Nursing diagnosis and interventions in a patient with multiple organ failure -- report of a case]

This study tries to identify Nursing Diagnoses and Interventions. It was done with a patient who was in critical health condition: multiple organs failure, in an Intensive Care Unit of a general hospital in Porto Alegre. The Case Study was the methodology used. Nursing Diagnoses is described mostly using NANDA Taxonomy. They are: Risk for Aspiration, Disuse Syndrome, Diarrhea, Risk for Infection, Impaired Tissue Integrity; and a Collaborative Problem was identified: Hypoglicemia. We have elaborated 34 Nursing Interventions for those diagnoses.

Renal dysfunction in patients with sickle cell anemia or sickle cell trait

Patients with sickle cell anemia (Hb SS) or sickle cell trait (Hb AS) may present several types of renal dysfunction; however, comparison of the prevalence of these abnormalities between these two groups and correlation with the duration of disease in a large number of patients have not been thoroughly investigated. In a cross-sectional study using immunoenzymometric assays to measure tubular proteinuria, microalbuminuria, measurement of creatinine clearance, urinary osmolality and analysis of urine sediment, we evaluated glomerular and tubular renal function in 106 adults and children with Hb SS (N = 66) or Hb AS (N = 40) with no renal failure (glomerular filtration rate (GFR) > 85 ml/min). The percentage of individuals with microalbuminuria was higher among Hb SS than among Hb AS patients (30 vs 8%, P < 0.0001). The prevalence of microhematuria was similar in both groups (26 vs 30%, respectively). Increased urinary levels of retinol-binding protein or beta 2-microglobulin were detected in only 3 Hb SS and 2 Hb AS patients. Urinary osmolality was reduced in patients with Hb SS or with Hb AS; however, it was particularly evident in Hb SS patients older than 15 years (median = 393 mOsm/kg, range = 366-469) compared with Hb AS patients (median = 541 mOsm/kg, range = 406-722). Thus, in addition to the frequently reported early reduction of urinary osmolality and increased GFR, nondysmorphic hematuria was found in 26 and 30% of patients with Hb SS or Hb AS, respectively. Microalbuminuria is an important marker of glomerular injury in patients with Hb SS and may also be demonstrated in some Hb AS individuals. Significant proximal tubular dysfunction is not a common feature in Hb SS and Hb AS population at this stage of the disease (i.e., GFR > 85 ml/min).

[Facial paralysis. Neuro-muscular reconstruction techniques]

Several surgical procedures have been proposed through the years for the treatment of facial paralysis. The multiplicity and diversity of techniques portray the complexity and challenge represented by this pathology. Two basic dynamic options are available: -Reconstruction of nerve continuity through direct micro suture, with interposition grafts or nerve transpositions. -Regional muscular transposition, most often using the temporalis. Facial reanimation with the temporalis transfer has withstood the test of time and still is a reference technique. In a few weeks, good results can be obtained with a single and rather simple surgical procedure. Functional free flaps have been used with increasing frequency in the last two decades, most often combining a cross-facial nerve graft followed by a gracilis free flap nine months later. With this method there is a potential for restoration of spontaneous facial mimetic function. Apparently there is a limit in microsurgical technique and expertise beyond which there is no clear improvement in nerve regeneration. Current research is now actively studying and identifying nerve growth factors and pharmacological agents that might have an important and complementary role in the near future.

[Inhalation lesions in the burn patient]

Inhalation injuries are currently the factor most responsible for mortality in thermally injured patients. Inhalation injuries may occur independently, but generally occur together with skin burn. Smoke inhalation affects all levels of the respiratory system and the extent of the inhalation injury depends on the duration, exposure, amount and toxicity of the fume temperature, concentration and solubility of toxic gases, the occurrence of the accident in a closed space and pre-existing diseases. Smoke inhalation also induces changes in the systemic organs with the need for more fluid for resuscitation. Systemic vasoconstriction, with an elevation in systemic vascular resistance, a fall in myocardial contractility and a great increase in lymphatic flow in soft tissue are the most important changes in systemic organs. On admission of a burn patient there is a high suspicion of inhalation injury when there are signs and symptoms such as hoarseness, strides, dyspnea, carbonaceous sputum, anxiety or disorientation, with or without face burns. The patient with these findings has partial airway obstruction and there is substantial risk complete airway obstruction occurring of secondary to the edema. Patients with suspected inhalation injury should be intubated so as to maintain airway patency and avoid a total obstruction. This group of patients frequently develop respiratory failure with the need for mechanical ventilatory support. Nosocomial infections, sepsis and multiple organ system failure may occur. Late complications of inhalation injury are tracheitis, tracheal stenosis or tracheomalacia and chronic airway disease, which is relatively rare. Early diagnosis of inhalation injury and treatment in a Burn Unit by a group of highly motivated clinicians and a good team of nurses is essential in order to decrease the morbidity and mortality related to inhalation injury.

Pharmacokinetic studies of 131I-stevioside and its metabolites

131I-STEVIOSIDE (1.10 MBq) was injected i.v in Wistar male rats, in distribution in the body and metabolism were studied. The highest concentration of radioactivity was observed in the liver and in the small intestine after 10 and 120 minutes, respectively. At 2 h after injection, the radioactivity eliminated in the bile was 52.0% of the original dose. The results of RP-HPLC analysis of the bile showed that stevioside was degraded in vivo and that steviol appeared as a major metabolite. However, in the urine; RP-HPLC analysis did not show the presence of steviol.

Massive experimental infection with Strongyloides venezuelensis in rats and absence of sudden death

Ten rats were divided into five groups, A - E, to determine the larval dose-effect of infection with Strongyloides venezuelensis (SVZ). The rat groups were exposed to SVZ infective larvae as follow: (A) 100, (B) 1,000, (C) 10,000, (D) 100,000 and (E) 1,000,000. The eight rats in Groups A - D survived the infection. Rats exposed to the higher doses of larvae had the higher egg per gram counts (EPG), but more rapid reduction in EPG counts. The four rats in Groups C and D had EPG counts greater than 10,000 EPG during days 7 - 21 after infection. Maximum EPG values in Group C were 85,400 and 106,600; those in Group D were 134,000 and 346,000. The two rats in Group E showed severe itching and bleeding on their digital pads at the time of infection. They became listless thereafter and died with hemorrhagic pneumonia at 4 days after infection. The sudden death that has been demonstrated in calves infected with massive doses of S. papillosus was not observed in SVZ-infected rats.

Clinical comparison between a glass ionomer cement and a composite for direct bonding of orthodontic brackets

The clinical performance of a glass ionomer cement for direct bonding of orthodontic brackets was compared with a composite resin routinely used in this procedure. Brackets were bonded, using both materials, in alternate quadrants of 16 patients of the Orthodontic Clinic of the State University of Rio de Janeiro. A total of 225 teeth, 112 in the glass ionomer cement group and 113 in the composite group, were tested. Bond failure frequencies were recorded for 12 months, and chi-square statistical test was carried out comparing the failure rates of the materials. The composite showed a statistically significant lower failure rate (7.96%) than the glass ionomer cement (50.89%), regardless of the dental arch tested. Although the glass ionomer cement presents important properties not observed in the composite, it is necessary to increase its cohesive strength to permit its clinical use for direct bonding of orthodontic brackets.

Prediction of mesiodistal diameter of unerupted lower canines and premolars using 45 degrees cephalometric radiography

The reliability of using the oblique cephalometric radiograph for early prediction of the mesiodistal widths of unerupted lower canines and premolars was investigated. Mandibular models and oblique cephalometric radiographs were obtained for 40 Brazilian children (20 boys and 20 girls), in the mixed dentition phase. Further models were obtained for the same sample when all permanent teeth had erupted. A Student t test showed statistically significant differences of tooth size between the sexes but not between right and left sides. Measurements of the unerupted canines and premolars taken from the 45 degrees cephalometric radiograph were statistically greater than the actual values, although a high correlation was observed between them. Linear regression equations and correction tables were established to compensate for this magnification. The actual values for these teeth were compared with the corrected predicted values from the 45 degrees radiograph and with the predicted values obtained from the methods of Ballard and Wylie, Carey, Moyers, and Tanaka and Johnston. A high correlation was observed only between the actual values and the corrected predicted values from the radiograph. The results indicate that, correcting the magnification, the 45 degrees cephalometric radiographic may be used in predicting unerupted lower canine and premolar widths in Brazilian children.

Direct bonding to porcelain

Orthodontic brackets were bonded to 180 faces of 45 porcelain cubes that were divided into three groups according to their surface preparation. In group I, the glaze had been removed with a sandpaper disk, whereas in group II, it was maintained. A solution of acidulated phosphate fluoride (APF) gel was applied to the samples in groups I and II for 5 minutes after pumicing. In group III, the glaze had been removed with a coarse diamond bur. Each group was further divided into four subgroups, depending on whether a priming agent had been used, and the type of composite used to bond the brackets. Shear force was used to debond the brackets, and the results showed that the APF solution was unable to provide enough retention on porcelain surface to bond brackets. Mechanical retention, obtained with a coarse diamond bur, was necessary to increase bond strength, which can be further improved by chemical bonding, with a silane priming agent. Therefore bonding to porcelain is clinically possible and is an acceptable procedure in orthodontic treatment.

Effect of different time intervals between sealant application and bracket bond on adhesive strength

The effect of variation of time between the use of the sealant and the composite itself on the bond strength of the enamel-resin-bracket system was tested in vitro for two composites. Eighty brackets were bonded to extracted human molars, half for each composite. The sealant was applied 1 minute, 2.5 minutes, 5 minutes, and 10 minutes before the use of the composite. The brackets were submitted to a shear force until debonding. Means and standard deviations were calculated. No statistically significant differences were found among the different times of sealant application and between the two composites tested, when a two-way analysis of variance was carried out.

Skeletal and dental arch asymmetries in Class II division 1 subdivision malocclusions

The aim of this study is to determine whether or not skeletal and/or dental asymmetries were presented in patients with Class II division 1 subdivision malocclusions. Frontal cephalometric radiographs and dental arch casts were obtained from thirty Brazilians from Rio de Janeiro; the mean age of the sample was 11.6 years. Nine bilateral triangles were established on tracings of the radiographs to describe the cranio-dento-facial complex. The area of each triangle was calculated, and the frequency of AP and transverse asymmetries on the dental casts were determined. When comparing Class I and Class II sides on the radiographs, Student t-tests did not show any statistically significant differences in triangle areas. However, the frequency of asymmetries on the dental casts were statistically significant at the 1% level. These asymmetries were more evident in the anteroposterior plane than in the transverse plane and in the lower arches than in the upper arches. It was concluded that Class II division 1 subdivision malocclusions are characterized by dental deviations and not skeletal dysplasia in the frontal plane.

Direct bonding brackets: unfilled versus unfilled/filled resins

The clinical and clinical/laboratorial performance of unfilled/filled and only unfilled resins for direct bonding of orthodontic brackets were evaluated. In the clinical part, brackets were bonded using both techniques in alternate quadrants of eleven patients of the Orthodontic Clinic, State University of Rio de Janeiro. A total of 118 teeth, 59 in each group, were tested and bond failure frequencies were recorded for six months. For the clinical/laboratory part, upper and lower premolars to be extracted for orthodontic reasons, were selected. Thirty-two brackets were bonded in vivo--16 using unfilled/filled and 16 using only unfilled resins--and the teeth were kept in the mouth for two months. After extraction, the teeth were secured in plastic rings and an Universal Instron Machine was used to debond the brackets. No statistically significant differences were observed for clinical failure rates, nor for laboratory debonding strength between the two techniques. Failures occurred preponderantly at the bracket/resin interface, so that most of the resin remained bonded to the enamel surface on both groups.

Polishing after debracketing: its influence upon enamel surface

The effect of different time periods of polishing, after debonding orthodontic brackets, upon enamel surface was investigated. Nine brackets were bonded onto nine healthy human teeth, extracted for severe periodontal disease. The brackets were removed after twenty-four hours and the composite was removed from the dental surface with a tungsten carbide bur. Three of these teeth were polished with a rubber cup, pumice and water for 30 seconds. Three others had the same procedure for 10 seconds and the last group did not received any polishing. The three groups were examined at the Scanning Electron Microscope and compared with the sound enamel of the same teeth. The results showed that pumicing is necessary after debracketing, although, even after 30 seconds of polishing, composite is still found on the enamel surface. The three procedures did not provide a surface equal to the sound enamel, but better results were obtained by increasing polishing time.

Direct bonded space maintainers

The aim of this study was to evaluate clinically a bonded space maintainer, which would reduce chair-side time and cost. Sixty appliances were fabricated from 0.7 mm stainless steel round wire and bonded using light-cured composite to the two teeth adjacent to the site of extraction of a posterior primary tooth. Twenty males and sixteen females (age range 5-9-years-old) were selected from the Pedodontic clinic of the State University of Rio de Janeiro. The sixty space maintainers were divided into two groups according to the site in which they were placed: a) absent first primary molar and b) absent second primary molar. Impressions and study models were obtained prior to and 6 months after bonding the appliances. During this period only 8.3% of failures were observed, most of them from occlusal or facial trauma. Student t-test did not show statistically significant alterations in the sizes of the maintained spaces during the trial period.

[Intestinal absorption of glucose in anesthetized rats. I. Standardization of a method for screening of oral hypoglycemic agents]

This paper presents a method for the screening of natural hypoglycaemic drugs that interfere with the intestinal absorption of glucose. Luminal perfusion of the small intestine (whole length) was carried out on 24 h fasted adult Wistar rats, anaesthetized with sodium pentobarbital. Two rubber Nelaton cannulae were introduced into the organ, the first at the proximal end of the duodenum, just after the pylorus and a second larger one near the ileo-cecal valve. After a preliminary washing with warm physiological saline to remove any alimentary residues and secretions, warm saline containing glucose (plain or with added putative absorption inhibitors), was then introduced into the gut. Ten minutes later the contents was expelled with air and the preparation fully washed with plain warm saline. All perfusates were separately collected up to volume in graduated flasks kept in chipped ice. The glucose concentration was measured in triplicate samples by the specific glucose-oxidase method. The intestinal absorption of the sugar was calculated by difference from the glucose concentration found in the initial solution and in the final perfusate. The method is reliable and highly reproducible.

The serum levels of unbound bilirubin that induce changes in some brain mitochondrial reactions in newborn guinea-pigs

Bilirubin in different concentrations was injected in newborn guinea-pigs and the following parameters were determined: serum total and unbound bilirubin, whole brain bilirubin content and oxygen consumption, NADH-cytochrome c reductase and ATPase activities in brain mitochondria. The results showed a significant correlation between decreased rates of brain metabolism and the elevation of serum total and unbound bilirubin.

Direct bond brackets: cotton roll versus rubber dam isolation

Forty-four brackets were bonded "in vivo" using cotton roll and rubber dam isolation. Maxillary and mandibular premolars, to be extracted for orthodontic reasons, were used in this study. After bonding, the teeth were retained in the mouth for at least 30 days. They were extracted using surgical elevators. After extraction, the teeth were secured in plastic rings using gypsum and kept in water for 7 days until debonding. A Universal Instron Machine was used to produce a shear force at a speed of 0.1 cm/min until each bracket was removed. No statistically significant differences for debonding strength were observed between the two types of isolation, nor between the buccal and palatal surfaces of the teeth. One hundred percent of the failures occurred at the bracket/composite interface.

Stability of the palatal rugae as landmarks for analysis of dental casts in extraction and nonextraction cases

To determine whether the positions of the palatal rugae were affected by orthodontic therapy, pre- and posttreatment maxillary dental casts of 57 adult patients treated in the graduate orthodontic clinic at the University of North Carolina were evaluated. The orthodontic extraction group (n = 27) was composed of patients whose treatment included the extraction of two maxillary premolars. The remaining patients (n = 30) had been treated without extractions. Transverse changes observed over time were significantly different from zero only for the medial points of the first rugae in the nonextraction group and for the lateral points of the first rugae in the extraction group. None of the changes observed in the transverse measures were statistically different between the two groups. In the extraction group, there were significant anteroposterior changes in the right lateral points between the first and second rugae and between the second and third rugae, and in the right medial points between the second and third rugae. There were no statistically significant anteroposterior changes observed in the nonextraction group over time. When the two groups were compared, the average distance between the lateral first and second right rugae, and the average distance between the lateral second and third right rugae were significantly different. The medial and lateral points of the third rugae appear to be stable landmarks for the construction of anatomic reference pints in longitudinal cast analysis.

Stability of the palatal rugae as landmarks for analysis of dental casts

The aims of this study were to determine if the palatal rugae are stable during normal growth, and whether treatment with either headgear or functional appliances affects the position of the rugae. Initial and 15-month recall dental casts of 94 patients enrolled in a study of early Class II treatment were evaluated. The children had been randomly assigned to one of three groups: control (n = 34), headgear (n = 30), and functional appliance (n = 30). Landmarks on the palatal raphe and palatal rugae were recorded using the Reflex Metrograph. A median palatal plane was constructed using the digitized raphe points as reference. Offsets from this plane to the ruga points and transverse and anteroposterior linear distances between ruga points were obtained for all casts. Transverse offsets and linear distances between medial points of the first rugae and the anteroposterior distances between the medial points of the second and third rugae did not show statistically significant changes in all groups. Significant changes were observed for the lateral points of the rugae, particularly in the headgear group. The medial rugae appear to be suitable anatomic points for the construction of stable reference planes for longitudinal cast analysis.