Maxillary and mandibular dental arch forms in a Jordanian population with normal occlusion.

BACKGROUND: Ethnic background has been claimed to affect arch form. The purpose of this study was to describe and elucidate the maxillary and mandibular arch forms in Jordanian population and to develop a classification method for these forms which could be employed to construct orthodontic archwires accordingly. METHODS: The sample was comprised of study casts of five hundred and twenty subjects (231 males and 289 females with a mean age of 15.4 ± 1.02 years). All subjects had permanent dentition with normal occlusion. A mathematical method associated with a polynomial function of 6th degree was employed to assess the dental arch forms. The resultant arch forms were classified into 5 groups for both the maxilla and mandible utilizing a computer software with special code designed for this study. Each group was subdivided into 3 subgroup sizes namely: small, medium, and large. RESULTS: Catenary arch form was found in 47% and 41.2% (p Ë‚ 0.01) of maxilla and mandible arch forms, respectively. Form 2 (which is halfway between ellipse and U-shaped arch form) was found in 27.7% and 26.7%. Medium size arch form was found in 55.4% of the maxillary and 65.6% of the mandibular arch forms. CONCLUSION: Catenary arch form was the most prevalent arch form, followed by wide elliptical form. The other forms, which included tudor arch, tapered equilateral and quadrangular forms were less frequent. Regarding size, the medium size was the most prevalent among the studied samples.

Assessment of the effects of a fluoride dentifrice and GC Tooth Mousse on early caries lesions in primary anterior teeth using quantitative light-induced fluorescence: a randomised clinical trial.

PURPOSE: To compare the effects of a fluoride dentifrice alone, versus a topical CPP-ACP crème used as a dentifrice, versus the combination of both agents (fluoride dentifrice followed by CPP-ACP crème) on early caries lesions (ECL) in primary anterior teeth of children over a 6-month period. METHODS: In this single blinded randomised clinical trial, children (n = 114, aged 4-5 years) with high caries risk and who had at least one ECL (ICDAS 2) on their primary anterior teeth were allocated to three groups. Subjects used different agents twice daily: fluoride dentifrice (500 ppm F, n = 42), CPP-ACP crème (10% w/v, n = 35), and the fluoride dentifrice followed by CPP-ACP crème (n = 37). Changes in lesions were tracked using QLF, comparing the baseline situation to 3 and 6 months of treatment. RESULTS: QLF changes consistent with mineral gain (∆F/fluorescence, lesion area) occurred in all three groups (baseline versus 3 months or 6 months, p ≤ 0.05 for all three groups). Differences between treatment groups were not statistically significant (p > 0.05). CONCLUSION: The topical CPP-ACP crème used alone gave effects similar to the fluoride dentifrice; however, the combination of the two did not give additive benefits over either agent used in isolation.

Vegetation and condition of arid rangeland ecosystem in Central Saudi Arabia.

Saudi Arabia rangeland ecosystems have undergone intense processes of degradation for many decades because of extreme climate and human activities such as overgrazing and socioeconomic changes. In this study, Hail and Qassim Regions of Saudi Arabia covering an area about 79610.73 km2 were selected to study the rangeland vegetation and condition. Haloxylon salicornicum was the most dominant species, covering more than 56% of the total area. The second prominent community was Acacia-Lycium shawii, which covers about 21% of total area. It was found that about 65% of vegetation in the surveyed area is in good or very good condition compared with about 31% in poor or deteriorated condition. Effective measures such as determination of carrying capacities and development of grazing systems have to be implemented to ensure resources sustainably.

Effect of salinity and temperature on germination, growth and ion relations of Panicum turgidum Forssk.

Seed germination of Panicum turgidum was significantly affected by salinity levels, temperature and their interaction. Maximum germination was noted in the lowest saline media (25-50 mM) and distilled water at the temperature of 15-25 degrees C and 20-30 degrees C. Seeds germination was substantially delayed and reduced with an increase in NaCl to levels above 50mM. This trend was much pronounced under high levels of NaCl and incubation temperature. Low levels of NaCl (25-50 mM) stimulated shoot and root dry weights of P. turgidum seedlings. However, the highest NaCl levels (>100 mM) resulted in a significant decrease in shoot, root and total dry weights of seedlings. Intermediate degrees of temperature, 15-25 and 20-30 degrees C, resulted in a significant increase in biomass accumulation. The Na+ concentration in shoots and roots significantly increased as NaCl concentration increased. The K+ concentration in roots and K/Na ratio in shoots and roots was significantly reduced as salinity concentration increased. The K/Na ratio was greatly affected by higher NaCl concentration and incubation temperatures.

Prevalence and persistence of C1q binding activity in healthy subjects.

Samples of serum from 885 normal healthy blood donors were tested for the presence of soluble immune complex-like material by a solid-phase C1q binding assay. The majority of donors (93%) had low or undetectable levels of C1q binding activity in their sera, but 6% had levels that were clearly outside the normal distribution. When these individuals were retested after several weeks half of them still had elevated levels of C1q binding activity.

Mesiodistal crown diameters of permanent teeth in Jordanians.

Mesiodistal crown diameters were measured from dental casts of the permanent teeth of 198 Jordanians (86 males and 112 females), aged 13.4-19.1 years. The differences in the crown diameters between the right- and left-hand sides of the dental arch were not significant, suggesting that either right- or left-side measurements could be taken to represent the tooth size of the study population. Males had significantly larger teeth than females, ranging from p < 0.05 for the incisors to p < 0.001 for the first molars. In both sexes, the maxillary lateral incisors showed the greatest variability [coefficient of variation (CV) 8.8%] and the first molar the least (CV 5.8%) in mesiodistal diameter. Canines displayed greater sexual dimorphism in crown size than any other tooth class. The cumulative tooth widths of males exceeded those of females by a sum of 3.1 mm in the maxilla and 3.6 mm in the mandible. These differences were statistically significant (p < 0.01). Comparisons of the mesiodistal crown diameters between population groups showed that Jordanians have tooth sizes close to those of Iraqis, but significantly larger than those of Yemenite-Jews, Caucasians and Chinese.

Maxillary and mandibular arch forms in the primary dentition stage.

OBJECTIVE: To determine the most common maxillary and mandibular arch form and size in primary dentition stage. MATERIAL AND METHODS: Four hundred thirty five preschool children were included in this study with an age range of 3.5-5.5 years old. Dental casts were digitized and landmarks for the measurements were identified and marked on each model. Ten points were determined on the dental arch. Measurements of the x and y coordinates of the 10 points of each dental cast image were plotted on a computer software to obtain the polynomial function that best describes the curve corresponding to the dental arch form. RESULTS: Three arch forms were observed; square, oval and tapered. The most common arch form observed in the primary dentition was the oval form (52%) followed by the square and tapered arch forms (29% and 19%, respectively). Gender differences were not detected. In the maxilla, the most common arch form was the oval (58.4%) arch whereas the square arch form (46.7%) was the most common in the mandible. The medium size arch form was the most common size in both mandible (83%) and maxilla (71.5%) and for the total sample (77%). Differences in arch form size distribution were detected (P<0.000). Small size arch form was more common in females compared to males in the maxilla and total sample (P<0.000). Intercanine width was significantly smaller in the tapered arch form compared to oval arch form (P=0.048). In both arches, intercanine and intermolar widths were significantly larger in males compared to females. CONCLUSIONS: The most common arch forms in the maxilla and mandible were the medium sized oval and square forms, respectively. Intercanine width was the smallest in the tapered arch form. Intercanine and intermolar widths were affected by gender.

Does acid etching enhance remineralisation of arrested white spot lesions?

AIM: To investigate the effect of acid etching procedure on the remineralisation of white spot lesions (WSL) which had undergone an initial phase of arrest, and to compare between the effect of fluoride and/or CPP-ACP on remineralisation before and after acid etching. STUDY DESIGN: In vitro study. METHODS: WSL were prepared in vitro on 130 human enamel slabs which were allocated into four experimental groups (N = 30) and one control group (N = 10). Changes in mineral content were registered weekly by Quantitative Light Induced Fluorescence QLF. When changes had arrested (after 8 weeks), the enamel surface of 20 slabs in each group were acid etched. The remineralisation process was continued until it slowed down again (after 5 weeks). RESULTS: Mean fluorescence gain was 13.7 ± 0.9% in the fluoride group, 16.5 ± 1.1% in the CPP-ACP group, and 11.4 ± 1.2% in the combination of fluoride and CPP-ACP group. CONCLUSIONS: There was a tendency toward better remineralisation after acid etching but this did not reach a significant level; the effect of etching was more pronounced in the presence of fluoride. Although CPP-ACP seemed to give a steadier rate of remineralisation over time when compared with fluoride, the overall remineralisation in the regimens was similar. In this model, combined treatment of fluoride and CPP-ACP did not have an extra benefit over the fluoride or CPP-ACP alone.

Serum factors influencing antibody-directed cell-mediated cytotoxicity (ADCC) and their effects on the detection of immune complexes by inhibition of ADCC.

An imporved assay system, using inhibition of ADCC, for the detection of 0.6 microgram/ml. of aggregated IgG in medium is described. Under these conditions, normal human serum is extremely inhibitory, this effect being attributed mainly to the weak binding of monomeric IgG. Enhancement of ADCC by albumin was also observed. Using this assay system without further modification, immune complexes may be detected in gel-fractionated sera by the distribution of the inhibitory material relative to the IgG peak. However, for routine use in the assay of untreated sera, a modification of the method is required. Preincubation of the spleen cells with the serum in the presence of EDTA, followed by a washing stage, reduces the background inhibition by normal sera to a low level. Effects of serum factors in producing variable amounts of background inhibition or stimulation are also avoided. The modified assay is sensitive to 6 microgram/ml of aggregated IgG in neat serum.

Monitoring the caries process. Optical methods for clinical diagnosis and quantification of enamel caries.

Early detection of a caries lesion would enable the dentist, by using effective prophylactic measures, to enhance remineralization and conservation of the tooth substance rather than restoration of the dentition. The presently-used diagnostic methods of detecting early lesions require visual observation. Reflected light is used to detect changes in color, texture, and translucency of the tooth substance. Attempts to improve the traditional methods or to develop new ones have been numerous. For clinical use, only 2 quantitative methods are presently available: (i) a method based on the scattering of light by enamel crystals in relation to their surrounding environment, and (ii) a method that uses visible laser light within the blue-green region as the light source to excite the autofluorescence of enamel. The possibilities and limitations of these methods are evaluated, and clinical applications are presented and discussed.

Inhibition of antibody-dependent cell-mediated cytotoxicity (ADCC) as a means of detection of immune complexes in the sera of patients with thyroid disorders and bronchogenic carcinoma.

Circulating immune complexes in the sera of patients with thyroid disorders or bronchogenic carcinoma were investigated using an assay system based on the inhibition of the ADCC activity of rat spleen cells. Increased inhibition, as compared with that of the sera of age and sex matched controls, was found in patients with thashimoto thyroiditis, primary hypothyroidism and bronchogenic carcinoma. The degree of inhibition in the first two groups was markedly increased compared with control sera of the same IgG content. However, the results in the lung cancer group were slightly but not significantly greater than in controls with the same level of IgG. Increased IgG levels were found in patients with thashimoto thyroiditis and thyrotoxicosis, and also in patients with bronchogenic carcinoma who had mediastinal gland involvement. The lower level of sensitivity of the assay system was approximately 600 ng added aggregated IgG, corresponding to a concentration of 6mu g/ml in the sample assayed. It is possible that circulating immune complexes may exist in lung cancer, but at a level below that of the present assay system.

Application of quantitative light-induced fluorescence to monitor incipient lesions in caries-active children. A comparative study of remineralisation by fluoride varnish and professional cleaning.

The aim of this study was to apply the quantitative light-induced fluorescence (QLF) method in a randomised controlled study, comparing treatment with fluoride varnish and professional tooth cleaning for remineralisation of white spot lesions in caries-active adolescents. In the fluoride varnish group (n = 13; 32 lesions), professional tooth-cleaning was followed by application of fluoride varnish at the beginning of the study, after 1 wk, and then once every 6 wk for 6 months. The other group (n = 18; 30 lesions) underwent professional tooth-cleaning once every 6 wk for 6 months. Enamel fluorescence was measured at baseline and at each visit. In the fluoride varnish group there was a significant change over time (baseline: 6 months) for both lesion area: and average change in fluorescence (decreased lesion area and increased fluorescence radiance). The corresponding changes in the professional tooth-cleaning group were not significant. There was a significant difference in average change in fluorescence between the two test groups. For lesion area, there was no significant difference, but a tendency towards a difference between the test groups. It was concluded that (a) the QLF method is a sensitive method, suitable for longitudinal quantification of incipient caries lesions on smooth surfaces; and (b) that repeated fluoride applications had a favourable effect on the remineralisation of white spot lesions as measured after 6 months.

Laser fluorescence quantification of remineralisation in situ of incipient enamel lesions: influence of fluoride supplements.

The aims of this study were to test the laser fluorescence method for quantification of remineralisation in situ of enamel with incipient lesions and to evaluate the enhancement of remineralisation by fluoride (F) supplements when a F dentifrice was used on a regular basis by healthy young subjects. Enamel samples were cut from extracted premolar teeth with the natural surface kept intact, and subjected to a pH-cycling system to produce subsurface demineralisation in vitro. The enamel blocks were then inserted into composite holders bonded to the buccal surfaces of both upper first molars of 12 panelists. Each panelist participated in 3 separate experiments in a randomised order; each lasted for 5 weeks with washout intervals of 2 weeks between experiments; experiment 1: F dentifrice (0.145% F as NaF) only; experiment 2: F dentrifice + F lozenges (0.25 mg F x 6/day); experiment 3: F dentifrice + F chewing-gum (0.25 mg F x 6/day). Fluorescence radiance was measured before, during, and after in vitro demineralisation, and once a week during the in situ experimental periods. The enamel samples were then sectioned and analysed with transverse microradiography (TMR). Anova and Pearson correlation coefficient were used for the statistical analysis. At the end of the 5-week in situ periods, fluorescence radiance had been regained to a level of 80-100% of the value before in vitro demineralisation, indicating remineralisation of the enamel samples. There were no differences in the fluorescence radiance gain between the 3 different F exposures. However, there was a statistically significant time trend (p < 0.001), and a highly significant linear dependence (p < 0.001) between the final measurements obtained with the laser fluorescence method (LAF) and the data obtained from TMR, r = 0.76. It was concluded that: (1) with the sensitive LAF method it was possible to register the small changes in the enamel week by week during in situ remineralisation: (2) when F dentrifice was used regularly, F supplements such as F lozenges or F chewing-gum did not significantly enhance the in situ remineralisation of incipient enamel lesions in healthy, young adults with normal salivary flow.

A longitudinal laser fluorescence study of white spot lesions in orthodontic patients.

Orthodontic treatment with fixed appliances increases the caries risk in young persons. The aim of this study was to apply a new caries diagnostic method, quantitative laser fluorescence, for longitudinal in vivo quantification of changes in incipient enamel lesions related to fixed orthodontic appliances. Seven young patients with active caries lesions disclosed at removal of the orthodontic brackets and bands were enrolled in the study. Caries preventive measures were intensified, including dietary advice, oral hygiene instructions, and the regular use of a fluoride dentifrice. The caries lesions were monitored with the quantitative laser fluorescence method after removal of the brackets and once a month thereafter. For each lesion, three quantities were measured: lesion area (mm2), mean fluorescence loss (%) over the lesion, and maximum loss of fluorescence (%) in the lesion. During a 1-year follow-up period, the areas of the lesions decreased and the enamel fluorescence lost was partly regained indicating that a remineralization process had occurred. It was concluded that quantitative laser fluorescence seems suitable for in vivo monitoring of mineral changes in incipient enamel lesions, and useful for the evaluation of preventive measures in caries prone persons, such as orthodontic patients.

Effect of acid-etching on remineralization of enamel white spot lesions.

This in vitro study aimed at investigating whether full remineralization would occur in white spot lesions when the surface porosity was increased by acid-etching. The effect of fluoride was also investigated. Enamel blocks with in vitro produced white spot lesions were used. Group A was exposed to a remineralizing solution only. In group B, the lesions were etched with 35% phosphoric acid for 30 s, then treated as in group A. Group C was treated as group A + daily treatment with a fluoride toothpaste slurry (1,000 ppm) for 5 min. Group D was treated as group B + the daily fluoride treatment of group C. The remineralization was measured weekly with Quantitative Light-induced Fluorescence during the experimental period. After 10 weeks of remineralization, mineral profiles were assessed with transverse microradiography. The enamel fluorescence was partly regained. There were significant differences in the lesion depth, mineral content at the surface layer, and integrated mineral loss between the groups. Addition of fluoride accelerated the remineralization only in the beginning; in later stages the process leveled out and even reached a plateau in all the groups. It was concluded that full remineralization was not achieved by etching, by the addition of fluoride, nor by the combination of both treatments in this in vitro study.

Mineral loss in incipient caries lesions quantified with laser fluorescence and longitudinal microradiography. A methodologic study.

The laser fluorescence method (LAF) was validated with longitudinal microradiography (LMR) for assessment of mineral loss in incipient caries lesions in human enamel. Fluorescence radiance scans and LMR recordings were made of 36 enamel slabs with incipient lesions. Original sound values for fluorescence radiance and enamel amount (kg.m-2) at the lesion site were reconstructed by a computer algorithm. Changes in fluorescence radiance and amount of enamel in each measuring point were calculated. The reconstruction method was tested on 20 sound enamel surfaces. The differences between measured and reconstructed values were -0.13 +/- 0.17% with LAF and 0.002 +/- 0.005 kg.m-2 with LMR. The repeatability of the caries quantification was tested by measuring one lesion 20 times. The fluorescence loss in this lesion was 18.2 +/- 1.0%. The enamel loss was 0.09 +/- 0.02 kg.m-2. The correlation between measurements with the two methods was r = 0.73. The non-destructive laser fluorescence method was concluded to be a sensitive and valid method for quantification of mineral loss in enamel caries lesions.

Light-induced fluorescence studies on dehydration of incipient enamel lesions.

Changes in the hydration state of enamel affect its optical qualities, such as light scattering and fluorescence. In this study, the rate of fluorescence loss was measured when incipient enamel lesions with different de-remineralization history were left to dehydrate. Four groups of lesions were studied. In groups A, B and C, the lesions were prepared in vitro in an acid-gel system. Group A was kept as control, and groups B and C were remineralized (4 weeks) without and with 1 ppm F in solution, respectively. Group D consisted of natural incipient lesions. Enamel fluorescence was measured for all lesions immediately after removal from water and subsequently at short intervals for 30 min. The change in fluorescence with dehydration varied between the groups. In lesions from groups A and B, it followed a double exponential decrease, while in lesions from groups C and D, it followed a mono-exponential decrease. In all groups, the fluorescence of sound surfaces declined mono-exponentially. The 'fractional fluorescence difference', defined as (L(sound) - L(carious) )/L(sound), became constant after periods of dehydration of about 5, 5, 20 and 5 min for groups A to D, respectively. The observation of the change of fluorescence with dehydration should be taken into consideration when planning studies that use fluorescence as an assessment method. However, it might also be used to gain insight into the properties for fluid transport inside the various lesions, relevant to de-remineralization or fluoride treatments.

Quantification of formation and remineralization of artificial enamel lesions with a new portable fluorescence device.

Quantitative laser fluorescence has been reported as a useful method for the non-destructive in vitro and in vivo diagnosis of early enamel caries. A portable system for intraoral use has been developed with a new light source and filter system replacing the laser light to facilitate clinical application. This new device was validated with microradiographic and chemical analyses for assessment of mineral changes in enamel during lesion formation and remineralization in vitro and compared with the laser light equipment. A significant correlation was found between fluorescence changes and mineral loss: r = 0.79 (laser system) and r = 0.84 (portable lamp system). The correlation between the two fluorescence methods was r = 0.93. The portable fluorescence device seemed to be a promising new tool for reproducible and sensitive assessment of the severity of incipient enamel lesions.