Health in Down syndrome: creating a conceptual model.

BACKGROUND: Down syndrome (DS) has a unique medical and psychological profile that could impact how health is defined on three dimensions: physical, social and mental well-being. METHODS: In 2021, we presented our proposed conceptual model to three expert panels, four focus groups of parents of individuals with DS age 0-21 years and four focus groups of individuals with DS age 13-21 years through videoconferencing technology. Participants gave feedback and discussed the concept of health in DS. RESULTS: Feedback from participants resulted in iterative refinement of our model, retaining the three dimensions of health, and modifying constructs within those dimensions. Experts and parents agreed that individuals with DS have unique health concerns that necessitate the creation and validation of a syndrome-specific health model. We present key themes that we identified and a final conceptual model of health for individuals with DS. CONCLUSION: Health in DS is a multi-dimensional, multi-construct model focused on relevant constructs of causal and effect indicators. This conceptual model can be used in future research to develop a syndrome-specific measure of health status.

Temporary reversal by topotecan of marked insulin resistance in a patient with myelodysplastic syndrome: case report and possible mechanism for tumor necrosis factor alpha (TNF-alpha)-induced insulin resistance.

Tumor necrosis factor-alpha (TNF-alpha) is an important mediator of insulin resistance in obesity and diabetes through its ability to decrease the tyrosine kinase activity of the insulin receptor. We report here a remarkable degree of insulin resistance in a patient with adult respiratory distress syndrome and myelodysplasia.

Effect of dentin desensitizers and dentin bonding agents on dentin permeability.

PURPOSE: To determine the effect of dentin desensitizing agents (oxalates and glutaraldehyde) and dentin bonding agents, with and without resin-based composite (RBC) on dentin permeability and morphology of the dentin surface. The influence of saliva and toothbrushing on these agents was also evaluated. MATERIALS AND METHODS: Radicular dentin discs +/-1 mm thick were obtained from extracted human teeth. The thickness of the discs was standardized by grinding them with 600 grit silicon carbide powder. Both pulpal and periodontal surfaces of the discs were treated with 6% citric acid for 2 min prior to the baseline measurement of dentin permeability. Permeability was measured for the discs, using a split-chamber apparatus, at four different time points: at baseline, after treatment with each desensitizing modality, after 24 hrs of saliva immersion and after simulated toothbrushing equivalent to 3 weeks of normal brushing. The treatment modalities were: Sensodyne Dentin Desensitizer, Gluma Dentin Desensitizer, All-Bond DS (primers without etching), Etch+Primers (All-Bond 2 system), Etch+Primers+Adhesive and Etch+Primers+Adhesive+RBC (AElite Flo). Radicular dentin discs were prepared separately for scanning electron microscopy (SEM). One group was left untreated as the control group. Discs in the other groups were treated with the modalities listed above. One disc from each group was viewed under the SEM after treatment with the desensitizing modality. The second disc in each group was viewed after 24 hrs of saliva immersion following desensitizing treatment and the third disc after 3 weeks of simulated toothbrushing following desensitizing treatment and saliva immersion. RESULTS: The greatest reduction in permeability was caused by All-Bond DS followed by Sensodyne Dentin Desensitizer and Etch+Primers+Adhesive+RBC. Gluma Dentin Desensitizer, Etch+Primers, and Etch+Primers+Adhesive did not reduce permeability by a significant amount. Saliva immersion increased permeability significantly only for the Gluma and Etch+Primers+Adhesive groups. There was a trend towards increase in permeability after toothbrushing; however, this increase was not statistically significant for any group (P > 0.05). Thus, placement of primers without etching (All-Bond DS) reduced permeability more than any other treatment modality. These data indicate that etching a sensitive dentin area may be appropriate only if RBC is to be placed in the area. Exposure to saliva and toothbrushing countered the decrease in permeability caused by dedicated desensitizers and dentin bonding agents. The SEM micrographs revealed that in most cases, form corroborated function and the morphology of the dentin surface corresponded to the dentin permeability values.

An evaluation of root canal treatment in patients who have received irradiation to the mandible and maxilla.

OBJECTIVE: The purpose of this study was to evaluate the success and failure of root canal treatment performed in areas of previous irradiation and to examine any cases of osteoradionecrosis associated with such treatment. STUDY DESIGN: A retrospective analysis was done on 22 teeth that had root canal treatment after radiation therapy. Strict radiographic and clinical criteria were used to determine success and failure. RESULTS: There was a mean follow-up period of 19 months. Of 22 cases, 20 (91%) were considered successful. Both failures occurred with a diagnosis of pulpal necrosis. There were no occurrences of osteoradionecrosis. CONCLUSIONS: Our study showed that root canal treatment in previously irradiated patients may be successful. In addition, treatment approaches, as well as the criteria for success and failure, should be the same for irradiated patients as for those who have not received radiation treatment.

HIV-positive patients differ from HIV-negative patients in indications for and type of UV therapy used.

BACKGROUND: Treatments using UV, UVB, or oral psoralen and UVA (PUVA) have been advocated for the care of HIV-infected persons with skin diseases. Concerns about the safety of these treatments exist. OBJECTIVE: We attempted to determine the characteristics of HIV infected persons receiving UV therapy and establish the reasons for and type of treatment administered. METHODS: During two 2-week periods, we prospectively ascertained basic information on all patients treated at 40 phototherapy clinics and detailed clinical information on patients known to be infected with HIV. RESULTS: We identified 3716 persons receiving UV therapy, including 311 known to be infected with HIV. When compared with patients not known to be infected with HIV, HIV-positive patients were significantly more likely to be treated with UVB rather than PUVA and were more likely to be treated for pruritic conditions rather than psoriasis. CONCLUSION: There were great variations in the relative reliance on UVB and PUVA among centers. There appears to be no agreement as to which type of UV therapy is optimal for patients infected with HIV. Most patients known to the treating clinician to be HIV positive are in the advanced stages of HIV disease. The number of persons with less advanced HIV disease receiving treatment remains unquantified but may be even more clinically important.

Vasculature of the dental pulp of atherosclerotic monkeys: light and electron microscopic findings.

Arteriosclerosis is a pathological condition in which there is a severe luminal narrowing of arterioles, resulting in tissue ischemia and necrosis. Arteriosclerosis has been reported in the dental pulp of normotensive persons as young as 40 yr of age. To date, no corroboration of these findings have been published. Our study examined pulp from atherosclerotic monkeys for such changes under controlled conditions. The lingual artery and canines from 11 nonatherosclerotic (control) and 11 atherosclerotic (experimental) cynolmolgus monkeys were histologically evaluated with light and transmission electron microscopy. Lingual arteries from controls did not exhibit atherosclerotic plaques, whereas those of the experimental monkeys did show fibro-foamy plaques. However, neither experimental nor control animals exhibited any arteriosclerotic alterations in the pulp. Our study concluded that, in this animal model, which did demonstrate atherosclerosis in the oral cavity, no similar alterations were found in the pulp.

Orthodontic bracket removal using conventional and ultrasonic debonding techniques, enamel loss, and time requirements.

The purpose of this study was to examine the effects of ultrasonic orthodontic bracket removal and cleanup and compare them with conventional debonding and cleaning of the enamel surfaces with burs and polishing disks. The amount of enamel loss and time for bracket removal and clean-up were also addressed. Thirty extracted human premolars were collected. The teeth were randomly placed in one of the three debonding groups: debonding with orthodontic pliers and enamel clean-up with finishing burs and polishing disks (group 1), debonding with orthodontic pliers and ultrasonic clean-up of the enamel surface (group 2), and ultrasonic debonding enamel clean-up (group 3). The teeth were stored for 48 hours in 100% humidity before bracket removal. All brackets were then removed. Polyvinyl siloxane impressions were made before and after bracket removal. Direct measurements of the teeth in micrometers were made at all steps. An additional 30 teeth were similarly prepared, and the brackets were debonded and cleaned-up as in the three groups previously described. The total time for bracket removal and enamel clean-up for each group was recorded in seconds.(ABSTRACT TRUNCATED AT 250 WORDS)

Accuracy of the Endex with variations in canal irrigants and foramen size.

Several electronic apex locators (EALs) are currently available. The manufacturer of a new device, the Endex, claims that it is accurate regardless of canal conditions. This study compared the accuracy of the Endex with that of the Exact-a-pex, the Sono-Explorer Mark III, and the Neosono-D SE as to the effects of fluids in the canal and variation in foramen size. Sixty extracted single-canaled teeth were divided into two groups (narrow and wide foramina), depending on whether the apical foramina permitted the tip of a #30 K file to pass through. An in vitro model was used, in which teeth were fitted in test tubes with the roots immersed in 1% agar in phosphate-buffered saline. Root canal lengths were measured in dry canals, then with ethanol, Xylocaine, and sodium hypochlorite in the canals by each electronic apex locator. These lengths were compared with those of the actual root canal lengths. No significant differences were noted among the instruments in dry canals regardless of the foramen size. The endex was generally superior to the other instruments examined in canals containing conductive fluids, especially where the apical foramen was widened.

A safe technique for removal of provisionally cemented crowns.

A technique is presented for removing full-cast crowns and porcelain crowns that have been temporarily or provisionally cemented. A rubber dam retainer clamp with rubber dam attached is placed on the crown and clamped near its margins. Steiglitz forceps are used to apply pressure and leverage. The assembled unit is removed with the Steiglitz and safely removes the loosened crown from the mouth.

Permeability effects of two dentin adhesive systems.

This in vitro study evaluated the effects of two dentin adhesive systems on dentin permeability. The XR-Bonding System modifies the smear layer but does not open dentinal tubules. The Kanca or "total-etch" technique (phosphoric acid, Tenure A and B, Scotchbond 2 Adhesive) removes the smear layer and opens dentinal tubules. Despite these differences, both systems reduced dentin permeability in a similar manner. XR-Bond decreased permeability to 52% of the smear layer value, while total etching reduced permeability to 66% of that value.

Regional variation in permeability of young dentin.

Variation in the permeability of dentin in people 19 years and less in age was evaluated. The regions compared were the occlusal third versus the middle third versus the cervical third of approximal surfaces. Also compared were the mesial approximal surface versus the distal. The comparison was done by obtaining 1 mm-thick dentin discs from the area of dentin close to the dentinoenamel junction. It was seen that the cervical area was significantly more permeable than the occlusal area. The middle third, though not statistically significant, had mean values almost twice those in the occlusal third and almost half of the values in the cervical third. No difference was seen in permeability between the mesial and distal surfaces. The reasons for these regional variations and their clinical implications are presented.

A comparison between Thermafil and lateral condensation in highly curved canals.

The obturation of highly curved canals often poses a problem for the clinician using lateral condensation. Recently, a product that incorporates guttapercha with a carrier (Thermafil) has been marketed. This study asked, "Was there a difference in apical microleakage of highly curved canals obturated with the Thermafil versus lateral condensation?" Twenty-two extracted human molars with canal curvature greater than 30 degrees were instrumented using a step-back technique. Teeth were placed in two groups of 10 teeth. Two teeth were controls. Canals were either obturated using sealer and lateral condensation, or sealer and the Thermafil technique. The access was closed with Cavit. Teeth were coated with wax and placed into India ink for 48 h. The wax was removed and teeth were cleared. All teeth were evaluated for linear dye penetration using a x7 viewer. A t test resulted in t = 0.137 (p > 0.05). Mean leakage for teeth obturated with the Thermafil was 1.15 mm and was 1.09 mm for lateral condensation. The Thermafil technique resulted in similar dye penetration to lateral condensation in highly curved canals.

Vertical root fracture and relative deformation during obturation and post cementation.

There are several speculated etiologies of vertical root fractures such as pressure exerted during post placement and excessive forces during lateral condensation. However, there are no reports comparing these two forces by use of the same measurement system. This study determined and compared on single-rooted teeth (1) the amount of strain to the root that occurs during obturation and post cementation and (2) the incidence of incomplete and complete vertical root fractures occurring during the aforementioned procedures. Canals of 32 extracted maxillary central incisors were step-back prepared. Teeth were randomly divided into negative and positive controls and experimental groups. The amount of root distortion was recorded with a strain gauge during each of the following procedures: (1) lateral condensation, and (2) lateral condensation plus cementation of a cast gold post. Relative deformations were compared statistically. Teeth were examined by transillumination and stereomicroscopy for incomplete and complete fractures and compared among groups. Data showed significantly more relative deformation with placement of a post and loading than with obturation alone. The accumulation of strain from both procedures did not significantly increase incidence of vertical root fractures. The results indicate that stresses from cementation of posts is more likely to cause relative deformation of roots.

Anatomical and histological features of C-shaped canals in mandibular second molars.

The mandibular second molar has many root canal variations. This investigation used two evaluation methods to examine the canal morphology of mandibular second molars having C-shaped canals. Fifteen extracted mandibular second molars with a conical root and C-shaped canal orifice were separated into two groups. A polyester cast resin technique allowed three-dimensional visualization of the root canal system in eight teeth; the remaining seven molars were prepared for histological examination in cross-section in the coronal, middle, and apical thirds for study under the light microscope. The results illustrated that C-shaped canals in mandibular second molars can vary in number and shape along the length of the root with the result that debridement, obturation, and restoration in this group may be unusually difficult.

Canal markings produced by endosonic instruments.

It has been recognised that ultrasonic files leave a diagonal pattern within the canal following endosonic instrumentation. There is confusion on the causative factor on the production of these marks. Furthermore there is little information about the marks produced by sonic files. An in vitro system consisting of highly polished dentin discs demonstrated that the ultrasonic K-file made a diagonal pattern that was an imprint of the cutting edges of the file. The sonic files produced different markings which were the result of their longitudinal and transverse motion. Root canals of extracted teeth were prepared with these instruments and similar grooves were observed. The ultrasonic K-file had diagonal grooves in the coronal and middle third of the root canal but longitudinal marks in the apical third. The rispisonic and shaper files produced debris even in the presence of NaOCl. This debris was formed into discrete parallel bands. Both longitudinal and transverse grooves were present and the canal had many other scratches similar to those seen with the dentin discs. There were differences between the marks produced by either ultrasonic or sonic endosonic instruments but it is unknown whether this influences the long term prognosis of the root canal therapy.

Clinical factors associated with ledged canals in maxillary and mandibular molars.

No clinical studies have been done to explore the relationship of ledging to the clinical practice of endodontics. The purpose of this study was to examine 171 cases completed by third-year dental students and to identify variables that were associated with ledging. A total of 336 canals were examined and tooth number, canal location, working length, the master apical file size, and root canal curvature were recorded. Of 336 canals, 46% were found to have been ledged. Analysis of variance revealed that No. 15 had a significantly higher incidence of ledging. Working lengths and master apical file sizes were not found to be significant variables. The main factor consistently related to the presence of ledges was canal curvature. The number of ledged canals increased significantly after 20 degrees and surpassed the number not ledged after 30 degrees. Multiple regression with the use of the five categories as the dependent variables and ledging as the independent variable resulted in an r = 0.397 and F = 12.216, p less than 0.0001. Curvature was found to have the highest significant t value (7.412) followed by "teeth" (2.471), whereas no other categories were identified as being significant. All the determinants for ledging were not identified with this study, and further research is indicated.

Clinical evaluation of five electronic root canal length measuring instruments.

A previous in vitro study has shown high accuracy, but no clinically significant differences in a group of five electronic root canal length measuring instruments. The purpose of this study was to evaluate and compare the performance of the same group of instruments under clinical conditions and to correlate their accuracy to radiographic estimates of canal length. Five electronic root canal length measuring instruments were used to measure the working length to the "apex" in 20 single-rooted teeth scheduled for extraction. After extraction, the actual canal length was measured visually to a point just within the apical foramen. This length was compared with instrument length as determined electronically. The accuracy of the instruments in determining canal measurement within +/- 0.5 mm from the apical foramen varied from 55 to 75%. The differences between the instruments were not statistically significant. On average, all of the instruments except for the Endocater gave canal length measurements that were beyond the apical foramen. The variability of the measurements, which was comparable to that of estimates of canal length from preoperative radiographs, indicated that radiographic verification of the working length is still desirable.

A comparison of two temporary restorations: light-cured resin versus a self-polymerizing temporary restoration.

Temporary restorative materials are an important component of endodontic therapy. They must both adequately seal the access preparation between visits and protect the obturated canal(s) from microleakage until a permanent restoration can be placed. The efficacy of Cavit and T.E.R.M. (a new light-cured composite product) was compared with the use of a carbon black coronal microleakage protocol. The teeth examined had previously received coronal restorations. After the teeth were accessed, restored with Cavit or T.E.R.M., and exposed to the dye, they were cleared. Three-dimensional assessment then revealed that Cavit more consistently provided an effective seal. In addition, a great deal of microleakage was observed around the permanent restoration-tooth interface. This indicates that perhaps leaking permanent restorations should be removed in their entirety before initiation of endodontic treatment.

Ultrasonic condensation of gutta-percha: an in vitro dye penetration and scanning electron microscopic study.

Lateral condensation of gutta-percha with and without ultrasonic activation of the spreader was compared by use of dye penetration analysis and scanning electron photomicrographs of the gutta-percha fills in extracted human incisors and canines. The root canal fillings in three groups of 10 teeth each were laterally condensed using an ultrasonically activated spreader, a fine finger spreader, or a non-activated ultrasonic spreader. Significantly less apical dye penetration occurred when teeth were obturated using an ultrasonically activated spreader as compared with manual condensation with fine finger spreaders. The ultrasonically condensed gutta-percha mass was more homogeneous with fewer voids compared with gutta-percha masses from the two groups that were condensed without ultrasonic activation. A correlation between apical microleakage and the appearance of the gutta-percha mass was seen. All teeth with well-condensed, more homogeneous fillings had low dye penetration. All teeth with a high extent of dye penetration had poorly condensed, less homogeneous fillings. However, not all teeth that had poorly condensed fillings had high dye penetration.

An in vitro comparison of five root canal length measuring instruments.

Several new root canal length measuring instruments (RCLMI) have recently been introduced claiming superiority over older systems. The purpose of this study was to compare five models of these instruments with respect to their accuracy under a given set of specified conditions. The five RCLMI tested were: the, Exact-a-pex, the Endocater, the Neosono-D, the Apex Finder, and the Sono-Explorer, Mark III. The conditions tested were the accuracy of the instruments in determining the working length, the consistency of measurement following canal instrumentation and with conductive gutta-percha points in place, and the operation of the RCLMI in the presence of fluids frequently found in root canals during endodontic treatment. An in vitro model was used to test these instruments. A set of 20 teeth was tested using the conditions specified above. All data were compared using the mean difference from the actual canal length of the teeth. The results indicated that there were no significant differences among measurements derived from the five instruments, under the specified conditions. There was a slight variation of the measurements by all instruments when they were used following instrumentation and with the use of conductive gutta-percha points. When fluids were present in the canals, the reliability of the RCLMI depended on the electrical conductivity of the fluid tested. The poorest results were obtained when either sodium hypochlorite or blood were present in the canals.