Effects of stabilized stannous fluoride dentifrice on dental calculus, dental plaque, gingivitis, halitosis and stain: A systematic review.

OBJECTIVES: The aim of the present systematic review was to examine the scientific evidence for the efficacy of stabilized stannous fluoride (SnF2) dentifrice in relation to dental calculus, dental plaque, gingivitis, halitosis and staining. DATA AND SOURCES: Medline OVID, Embase.com, and the Cochrane Library were searched from database inception until June 2017. Six researchers independently selected studies, extracted data, and assessed methodological quality. A meta-analysis of the 6-month gingivitis studies was done. Risk of bias was estimated using a checklist from the Swedish Agency for Health Technology Assessment (SBU, 2018). STUDY SELECTION: Two studies on dental calculus, 21 on dental plaque and gingivitis, 4 on halitosis, and 5 on stain met the inclusion criteria. Risk of bias was high for the studies on dental calculus, halitosis, and stain, and varied for the dental plaque and gingivitis studies. Significant reductions in dental calculus and in halitosis were reported for the SnF2 dentifrice; no differences in stain reduction were noted. A meta-analysis on gingivitis found better results for the SnF2 dentifrice compared to other dentifrices, though the results of the individual trials in the meta-analyses showed a substantial heterogeneity. CONCLUSIONS: The present review found that stabilized SnF2 toothpaste had a positive effect on the reduction of dental calculus build-up, dental plaque, gingivitis, stain and halitosis. A tendency towards a more pronounced effect than using toothpastes not containing SnF2 was found. However, a new generation of well conducted randomized trials are needed to further support these findings. CLINICAL RELEVANCE: Adding a SnF2 toothpaste to the daily oral care routine is an easy strategy that may have multiple oral health benefits.

Physical therapists' assessments, analyses and use of behavior change techniques in initial consultations on musculoskeletal pain: direct observations in primary health care.

BACKGROUND: Behavioral medicine (BM) treatment is recommended to be implemented for pain management in physical therapy. Its implementation requires physical therapists (PTs), who are skilled at performing functional behavioral analyses based on physical, psychological and behavioral assessments. The purpose of the current study was to explore and describe PTs' assessments, analyses and their use of behavioral change techniques (BCTs) in initial consultations with patients who seek primary health care due to musculoskeletal pain. METHODS: A descriptive and explorative research design was applied, using data from video recordings of 12 primary health care PTs. A deductive analysis was performed, based on a specific protocol with definitions of PTs' assessment of physical and psychological prognostic factors (red and yellow flags, respectively), analysis of the clinical problem, and use of BCTs. An additional inductive analysis was performed to identify and describe the variation in the PTs' clinical practice. RESULTS: Red and yellow flags were assessed in a majority of the cases. Analyses were mainly based on biomedical assessments and none of the PTs performed functional behavioral analyses. All of the PTs used BCTs, mainly instruction and information, to facilitate physical activity and improved posture. The four most clinically relevant cases were selected to illustrate the variation in the PTs' clinical practice. The results are based on 12 experienced primary health care PTs in Sweden, limiting the generalizability to similar populations and settings. CONCLUSION: Red and yellow flags were assessed by PTs in the current study, but their interpretation and integration of the findings in analyses and treatment were incomplete, indicating a need of further strategies to implement behavioral medicine in Swedish primary health care physical therapy.

Efficacy of sealing the mesial surfaces of first permanent molars with respect to the status of the distal surfaces of the second primary molars in children at high caries-risk.

AIM: This study aimed at evaluating the efficacy of sealants at preventing caries development or arresting the progression of non-cavitated mesial carious lesions in first permanent molars (6m) with respect to the status of the distal surfaces of the second primary molars (05d). METHOD: The study population comprised 121, 8- to 10-year-old schoolchildren in a high-caries community in Valparaiso, Chile. They were examined clinically and radiographically and screened for caries-related risk factors using the risk-assessment software program Cariogram. The children were divided into three groups: Group A, with no caries lesions on adjacent surfaces of 05d-6m, served as a control group. Group B, with caries on 05d, received a preventive sealant on the caries-free 6m after temporary separation, and Group C, with carious 05d, received a therapeutic sealant on a 6m with initial lesions. Standardised follow-up radiographs were taken in 110 children after 12-14 months. RESULTS: In group A, with no treatment, the mean percentage of sound surfaces that developed caries lesions was 3.8%. In group B, the mean percentage of sound 6m surfaces that developed caries lesions was 4.9% for sealed and 22.0% for unsealed surfaces (p < 0.05). In group C, the progression of therapeutically sealed carious lesions on 6m was 3.0% compared with 41.2% for unsealed carious control surfaces (p < 0.05). CONCLUSIONS: These results suggest that sealing sound surfaces and non-cavitated caries in the proximal mesial surfaces of permanent molar teeth effectively prevents or reduces the progression of caries adjacent to lesions on the distal surfaces of the second primary molars.

Colonization of Streptococcus mutans and Streptococcus sobrinus genotypes and caries development in children to mothers harboring both species.

The major route of early acquisition of mutans streptococci in humans is a vertical transmission from mother to child. The purpose of this longitudinal study was to examine the acquisition, distribution and persistence of Streptococcus mutans and Streptococcus sobrinus in children whose mothers harbored both species and to study the caries incidence in relation to colonization of these bacteria. Fifteen mother-child pairs were followed during the child's first 7 years. Stimulated salivary samples were taken from the mothers and the children. Plaque samples were also collected from the teeth and the tongue of the children. The samples were analyzed by cultivating techniques together with genomic fingerprinting and hybridizing. The caries experience was evaluated on the sampling occasions and retrospectively using the records of caries registrations from the community clinics. During the 7-year period 10 of the 15 children acquired mutans streptococci. Only 4 of them were colonized by both S. mutans and S. sobrinus despite the fact that their mothers harbored both species. In 2 of the children S. sobrinus was found later than S. mutans. A total of 26 genotypes were found in the children and 9 of them were identical to their mothers. New genotypes and a gain-loss pattern were noted especially in the children but also in their mothers. The groups of teeth first positive for the two species were the deciduous molars. The caries experience was low during the study period with 8 children showing no caries.

A prospective study of a caries prevention program in pregnant women and their children five and six years of age.

A preventive dental program (PDP) instituted in pregnant women and comprising an educational and a preventive part was evaluated when their children were five and six years of age. Dental caries was examined in sixty-seven mother-child pairs belonging to the program and in sixty-nine control mother-child pairs. In the five-year-old children 87 percent of the PDP group were caries free compared with the 50 percent in the control group. Comparable figures for six-year-old children were 89 percent and 62 percent in the PDP and control group, respectively. The mean dft of the PDP children five and six years of age was 0.4 and 0.2, respectively, versus 1.3 and 1.4 for the control children. The differences in caries-free status and caries prevalence were statistically significant. In conclusion, the preventive dental program which started in pregnant women and continued in the mothers and their children were highly effective for a long-term reduction of dental caries.

Fluoride release in vitro from a resin-modified glass ionomer after exposure to NaF solutions and toothpastes.

The aims of the present investigation were: (i) to study the release of fluoride from a resin-modified glass ionomer cement (Vitremer) after exposing ("recharging") the material with NaF toothpastes and NaF solutions with different fluoride concentrations, and (ii) to study the effect of covering the material with a sealant layer (glaze) in this respect. Totally 160 specimens were made, which were placed in water for 13 weeks to receive a low fluoride release value. The specimens were then randomly divided into 10 groups with 16 discs each. Five of the groups were exposed once a day for 7 days to one of the following fluoride agents: 0.05, 0.2 or 2% NaF solutions and slurries of two NaF toothpastes (Acta and Pepsodent). The other five groups received the same treatment twice a day. All treatments had a recharging effect. However, the 2% NaF solution resulted in significantly more fluoride release than the other solutions and toothpastes. Treatment twice a day gave higher total release than once a day, but the difference were only significant for the 0.2 and 2% NaF solutions. With glaze material covering the specimens, almost no fluoride release was observed. However, when the glaze was removed, a burst of fluoride occurred.

An in vitro study of fluoride release from a resin-modified glass ionomer cement after exposure to toothpaste slurries of different pH.

The aim of the study was to evaluate the fluoride release from an aged resin-modified glass ionomer (Vitremer) after exposure to five toothpaste slurries with different pH values. Cylindrical specimens of the material were leached in de-ionized water for 3 months and then exposed for 30 min daily for 10 days to three dentifrice slurries (20 specimens/group) containing 0.05% fluoride with pH values of 2.6, 5.7 and 8.3 and two non-fluoridated slurries with pH values of 2.5 and 5.7. A neutral NaF solution (0.05% F) was used as a control. During the 30 min exposure time, the fluoride concentration was gradually decreased in order to imitate the clinical situation. Thereafter, specimens were immersed individually in de-ionized water and the fluoride release determined. After the first day of exposure, all groups except one without fluoride (pH 5.7) showed significantly (P < 0.05) increased fluoride release. After exposure to the fluoridated toothpaste slurry with pH 5.7, significantly (P < 0.05) more fluoride was released compared to the toothpaste slurry with pH 8.3. Low pH (2.5 or 2.6) of the slurry resulted in a significantly (P < 0.05) higher fluoride release, regardless of whether it was fluoridated or not. The total amount of fluoride released after exposure to the more acidic fluoride toothpaste slurry was greater than that released from the more acidic non-fluoride toothpaste and the less acidic fluoride toothpaste. Our data indicate that the fluoride release from the resin-modified glass ionomer studied may be increased after treatment with an acidified NaF-toothpaste.

Effect of professional flossing with NaF or SnF2 gel on approximal caries in 13-16-year-old schoolchildren.

The aim of this study was to evaluate the effect of professional flossing with NaF and SnF2 gels on caries development on approximal tooth surfaces. Two-hundred-and-eighty 13-year-old schoolchildren were divided into 3 groups: (1) NaF (n = 97), (2) SnF2 (n = 85), and (3) placebo gel group (n = 98). The investigation was carried out double-blind. The children were treated 4 times a year for 3 years with 1% NaF gel, 1% SnF2 gel, or placebo gel. The treatment was carried out by dental nurses and the time required per visit was approximately 10 min. After 3 years, the mean approximal caries increment, including initial caries lesions, was 2.8 in the NaF, 2.4 in the SnF2, and 4.0 in the placebo gel group (P< 0.05 for SnF2 vs placebo); a reduction compared to the placebo of 30% and 39% in the NaF and SnF2 groups, respectively. Thus, professional flossing with NaF or SnF2 gel carried out 4 times a year may be considered as an interesting caries-preventing method for large-scale application in schoolchildren.

Recolonisation pattern of mutans streptococci after suppression by three different modes of chlorhexidine gel application.

Clinical studies have shown conflicting results for the reduction of approximal caries when chlorhexidine gel has been applied either in trays or by flossing. To investigate whether these modes of treatment affect the colonization of mutans streptococci (MS) differently, we quantified MS in saliva and on various tooth surfaces before and after a single chlorhexidine gel application. Twenty-one schoolchildren (15-16 yr old), with high numbers of salivary MS, were randomised into three groups. The subjects were treated with a 1% chlorhexidine gel applied either by: 1) interdental flossing; 2) individually designed mouth trays; or 3) a combination of polishing and flossing. Analysis of saliva and of dental plaque from 12 sites over an 8-wk period showed a greater reduction of both salivary MS counts and total number of colonised sites in the tray group than in the flossing group. The effect on MS in the polishing-flossing group approached that obtained in the tray group. In the interdental areas, more sites had no detectable MS (score 0) after tray treatment than after flossing, whereas the reduction of heavily colonised sites (scores 3+/-4) was higher in the flossing group. The reappearance of sites with score 3+/-4 after the gel treatment was more rapid in the flossing group than in the other two groups. In conclusion, the results showed a transient reduction of MS colonisation by all three methods, and that the application of the chlorhexidine gel both in mouth trays or as a combination of polishing and flossing was more effective in reducing the MS population than flossing alone.

Dental caries and caries-associated microorganisms in Uruguayan preschool children.

The prevalence of dental caries was studied in 3-5-year-old Uruguayan children (n = 76) living in 2 areas with different socioeconomic and cultural conditions. More children from the low socioeconomic area of Las Acacias had caries (68%) than children from the middle- to high-class neighborhood of Pocitos (19%). They also had poorer oral hygiene and a significantly higher caries prevalence (P < 0.05) than those from Pocitos. The occurrence of mutans streptococci and lactobacilli was determined in whole unstimulated saliva and compared with that in debris collected with a loop from the dorsum of the tongue. Mutans streptococci were detected in 42% of the children with significant correlations between the salivary levels of the microorganism and caries experience. Lactobacilli were recovered less frequently (18%). The detection of mutans streptococci in the tongue-loop samples was significantly correlated with that in whole saliva.

Effect of NaF-, SnF2-, and chlorhexidine-impregnated birch toothpicks on mutans streptococci and pH in approximal dental plaque.

The antimicrobial effect of birch toothpicks impregnated with 4% NaF, 8% SnF2, or 2% chlorhexidine was studied both in vitro and in vivo. A non-impregnated toothpick served as a control. In vitro, suspensions of Streptococcus mutans were exposed to the various toothpicks for 20 min and then cultured on blood agar. The results of this susceptibility test revealed the following ranking order with respect to inhibition: chlorhexidine > SnF2 > NaF and non-impregnated; with significant differences in colony-forming units (CFU) between these three groups. In vivo, 12 individuals used the 4 types of toothpick 3 times a day for 5 days in a procedure with a crossover design. Saliva and approximal plaque samples were collected at baseline and on various occasions up to 23 days after the treatment. At the same time, plaque-pH was measured at approximal sites 10 min after rinsing with 10% sucrose. The results of these in vivo experiments revealed lower proportions of mutans streptococci after using all four types of toothpick, but the reduction was significant only after 2 days for the toothpicks impregnated with SnF2 and chlorhexidine (P< 0.05). On the sampling occasions 9 and 23 days after the treatment, the mutans streptococci were more or less back to baseline levels again. In saliva no significant differences in the number of mutans streptococci were found either within or between the four treatments. No significant differences were found regarding decline in the plaque-pH between the NaF-, SnF2-, chlorhexidine-, and non-impregnated toothpicks on any of the sampling occasions.

Utilization of dental services in relation to socioeconomic and health factors in the middle-aged and elderly Swedish population.

The aims of this study were to describe the change in reported time since the latest visit to a dentist between the years 1980/81 and 1988/89 and the reported use of dental services in relation to age, dental state, and socioeconomic and health characteristics in a sample of the Swedish population in 1988/89. The studies are based on interviews by Statistics Sweden about the living conditions. In the investigations in 1980/81, 14,964 inhabitants between 16 and 84 years of age participated, and in 1988/89, 13,309 inhabitants. In all age groups there was a significantly higher frequency of reported visits to a dentist last year in 1988/89 than in 1980/81. In the age group 50-64 years old this figure increased from 54% to 75%, and in the age group 65-84 years old it increased from 26% to 39%. In the investigation in 1988/89 about 75% of the dentulous women in all age groups up to 75 years reported visiting a dentist last year. The relative risk for not visiting a dentist last year, adjusted for age, gender, and dental state, was higher in dentulous subjects with low income and education, not married, not native-born, living in rural areas, smoking, and low social and physical activity. The results of the logistic regression analysis showed that, among the elderly, functional ability and general health factors have lower significance for time since last visit to a dentist than socioeconomic, social support, and life-style factors.

Root caries and some related factors in 88-year-old carriers and non-carriers of Streptococcus sobrinus in saliva.

The prevalence of caries on exposed root surfaces in 88-year-old subjects with and without salivary levels of Streptococcus sobrinus was studied. Ninety-two individuals were examined with regard to root caries lesions and fillings. The root caries index (RCI) was calculated and related to salivary flow rate and buffer capacity, plaque score and salivary counts of Streptococcus mutans, S. sobrinus and lactobacilli. In 89 subjects with exposed root surfaces, all but 2 harbored mutans streptococci; 51 subjects carried S. mutans only, 35 both S. sobrinus and S. mutans, and 1 S. sobrinus only. The RCI was significantly higher in persons with than those without S. sobrinus (p < 0.05). Subjects with both S. sobrinus and S. mutans had higher counts of total mutans streptococci and lactobacilli than subjects with only S. mutans (p < 0.05). The RCI was significantly correlated to S. sobrinus and S. mutans (p < 0.05). The positive correlation between the RCI and S. sobrinus was still significant when the other tested variables were kept constant, whereas the correlation between the RCI and S. mutans was weaker when S. sobrinus and lactobacilli were kept constant. The D-component of the RCI (DSr%) was significantly correlated to S. sobrinus, S. mutans and lactobacilli, whereas the F-component of the RCI showed no significant correlation to any of the tested variables. A stepwise multiple correlation showed that the variance of DSr% was best explained in the S. sobrinus carriers by S. sobrinus and the salivary buffer effect, and in the non-carriers by S. mutans.

Dental caries and related factors in 88- and 92-year-olds. Cross-sectional and longitudinal comparisons.

Our aim was to compare two groups of 88- and 92-year-olds (n = 92 and n = 40), respectively, with regard to teeth, caries, and salivary and microbial conditions. Oral variables were analyzed in relation to functional capacity and use of cardiovascular agents and psychoactive drugs. Untreated root caries, plaque score, and counts of lactobacilli increased between the ages of 88 and 92 years (P < 0.01). Nine of the 24 longitudinally followed up subjects had lost 1-5 teeth over 4 years, and 17 subjects had developed new caries (DFS). The mean caries increment over 4 years was 1.3 coronal and 3.6 root surfaces, and new DFS per 100 surfaces at risk was 4.3 coronal and 17.5 root surfaces. Plaque score and final pH of buffer capacity increased (P < 0.05 and 0.01, respectively), whereas saliva flow, independent of gender, was unchanged. Use of cardiovascular agents and psychoactive drugs was associated with a deteriorated dental status.

Oral glucose clearance in nonagenarians in relation to functional capacity, medication and oral variables.

OBJECTIVES: To study oral sugar (glucose) clearance and to examine some factors which were believed to either influence or be dependent upon oral glucose clearance. DESIGN: Cross-sectional, clinical study with analysis of records. SETTING: Göteborg gerontological and geriatric population studies, Göteborg University, Sweden. SUBJECTS: 71 community-dwelling individuals, 27 men and 44 women, of a representative sample of 260 92-year-old persons. INTERVENTION AND MAIN OUTCOME MEASURES: Glucose concentration was measured in saliva after chewing of a glucose tablet and the clearance was assessed by three different variables: (i) the initial salivary glucose concentration, (ii) the area under the curve (AUC) and (iii) the clearance time. RESULTS: The glucose clearance showed a wide inter-individual variation, which could be explained partly by differences in oral state, chewing time, stimulated salivary secretion rate and medication use. A positive correlation was found between the clearance variables and the number of lactobacilli and mutans streptococci in saliva and the percentage of untreated root caries lesions of the total number of exposed root surfaces. CONCLUSIONS: A slow oral sugar clearance is more common among 92-year-olds than younger adults earlier reported in other studies, particularly in those who have uncompensated functional impairments and a high medication history. A decreased oral glucose clearance was associated with high counts of salivary lactobacilli and mutans streptococci and a high proportion of untreated root caries lesions.

Caries prevalence and salivary and microbial conditions in 88-year-old Swedish dentate people.

As part of a comprehensive investigation of 88-year-old people, caries prevalence, stimulated salivary secretion rate, buffer capacity, and the prevalence of lactobacilli and mutans streptococci were studied in a subsample of 92 dentate subjects. The mean number of remaining teeth was 14.1 +/- 7.3. The DMFT was 25.2 +/- 3.0, and DF surfaces 38.3 +/- 22.7. Root caries experience was found in 85% of the subjects, with a mean root caries index of 36.6 +/- 28.5%. The men had significantly higher mean values of salivary secretion rate (2.0 +/- 1.3 ml/min) than the women (1.1 +/- 0.6 ml/min) (p < 0.001). The mean final pH of buffer capacity was 6.3 +/- 1.3. High counts of lactobacilli (> 10(5)) and mutans streptococci (> 10(6)) were found in 49% and 55% of the subjects, respectively, of whom most were denture wearers. The mean number of total mutans streptococci was higher in persons harboring both Streptococcus mutans and S. sobrinus than in subjects with only S. mutans.

The toothpick method in relation to other plaque sampling techniques for evaluating mutans streptococci.

The aim of the present study was to compare the use of toothpicks with other sampling methods for determination of mutans streptococci on different tooth surfaces. In nine persons with > 10(5) CFU per ml saliva of mutans streptococci, plaque samples were taken from 90 buccal and lingual surfaces, 108 occlusal surfaces and 90 approximal surfaces with toothpicks. The prevalence of mutans streptococci on these tooth surfaces was compared with samples taken at four 1-week intervals on the same tooth surfaces with a carver (buccal/lingual surfaces), a needle (occlusal surfaces) or a dental floss (approximal surfaces). Each sample was plated on MSB agar and the presence of mutans streptococci was expressed on a scale varying from 0 to 4. On two of the sampling occasions the amount of plaque, mirrored by total viable counts on blood agar, was also determined. Only for buccal/lingual plaque samples was a difference in total counts between methods noted and then with higher total recoveries obtained after sampling with toothpicks. More surfaces were found to be positive for mutans streptococci when samples were taken with a toothpick than with a carver, needle or floss. On surfaces positive for mutans streptococci the colonization score was higher in samples taken with a toothpick than with a carver or a needle while samples taken with a floss showed a tendency to higher levels of mutans streptococci than samples collected with a toothpick. The data indicate that the results indicate that the results obtained by using toothpicks for evaluating the prevalence of mutans streptococci on individual tooth surfaces compare favorably with the other methods tested.

Effects of sugar restriction on Streptococcus mutans and Streptococcus sobrinus in saliva and dental plaque.

The effect of sugar restriction on the oral levels of mutans streptococci was studied in 20 subjects fulfilling three criteria: (1) having more than 300,000 CFU mutans streptococci/ml saliva, (2) harbouring both Streptococcus mutans and Streptococcus sobrinus in saliva, and (3) eating sugar frequently. The subjects were randomly divided into a test group (n = 12), who were asked to refrain from using sugar-containing foods between meals and to reduce sugar in main meals for 6 weeks, and a control group (n = 8), who did not receive any dietary advice. Saliva and plaque samples were collected at baseline and at 3, 6 and 12 weeks. The results showed that the levels of S. mutans and S. sobrinus decreased in saliva and plaque during the 6-week sugar restriction period. The decrese in mutans streptococci was more pronounced on buccal than on approximal tooth surfaces. Both species seemed to react in a similar way to the sugar restriction in saliva as well as in dental plaque. At the follow-up examination at 12 weeks, i.e. 6 weeks after completing the sugar restriction period, the numbers of S. mutans and S. sobrinus had increased again, but were still lower when compared to the baseline values.

Sucrose retention and colonization by mutans streptococci at different sites of the dentition.

The correlations between the retention and elimination of sucrose at different oral sites and the colonization by mutans streptococci at the same sites were tested in 10 subjects with > 10(5) mutans streptococci per millilitre of saliva. Paraffin-stimulated saliva was collected and plaque samples were taken with a toothpick from all the buccal surfaces except the third molars. One week after the plaque sampling, the sucrose clearance was determined. After a mouth rinse with 10 ml of a 10% sucrose solution, pre-weighed filter paper discs were placed at representative buccal sites of the interdental papilla between molars, premolars and incisors in the upper and lower jaw. The samples were collected 0.5, 2.5, 5.5, 8.5 and 12.5 min after rinsing. Analysis of the sucrose concentration was made using an enzymatic method. The oral sugar clearance was slower in the anterior region of the upper jaw than in the posterior regions and in the central region of the lower jaw. The frequency of mutans streptococci decreased towards the anterior teeth, with Streptococcus sobrinus predominating over Streptococcus mutans. A negative correlation was observed in the upper jaw between sugar clearance and retention and the prevalence of mutans streptococci, whereas the opposite tendency was observed in the lower jaw.

Potential efficacy of chlorhexidine against mutans streptococci and human dental caries.

Chemotherapeutic agents have been considered as having potential for the prevention of dental caries. Several substances have been evaluated as possible candidates, but no antimicrobial agent, with the exception of fluoride, has received as much experimental attention as the bisbiguanide chlorhexidine. This substance represents, so far, the most effective and best-documented agent. To be effective against caries, therapeutic dosages of the antimicrobial agent have to be given for a sufficient but finite time period to sites with established cariogenic plaque. In studies where this principle has been used, the aim has been to eliminate or strongly suppress the population of mutans streptococci. Of various antimicrobial agents and methods tested, the most persistent reduction of mutants streptococci has been achieved by chlorhexidine varnishes, followed by gels and mouthwashes. The best clinical effect resulting in a considerable caries reduction has been obtained when persons highly colonized with mutans streptococci have been treated with gels and when the results of the antimicrobial measures have been verified by microbiological examination.