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PubMed1990

The effects of processing requirements on neurophysiological responses to spoken sentences.

Ten English speaking subjects listened to sentences that varied in sentential constraint (i.e., the degree to which the context of a sentence predicts the final word of that sentence) and event-related potentials (ERPs) were recorded during the presentation of the final word of each sentence. In the Control condition subjects merely listened to the sentences. In the Orthographic processing condition subjects merely listened to the sentences. In the Orthographic processing condition subjects decided, following each sentence, whether a given letter had been present in the final word of the preceding sentence. In the Phonological processing condition the subjects judged whether a given speech sound was contained in the terminal word. In the Semantic processing condition subjects determined whether the final word was a member of a given semantic category. A previous finding in the visual modality that the N400 component was larger in amplitude for low constraint sentence terminations than for high was extended to the auditory modality. It was also found that the amplitude of a N200-like response was similarly responsive to contextual constraint. The hypothesis that N400 amplitude would vary significantly with the depth of processing of the terminal word was not supported by the data. The "N200" recorded in this language processing context showed the classic frontocentral distribution of the N200. The N400 to spoken sentences had a central/centroparietal distribution similar to the N400 in visual modality experiments. It is suggested that the N400 obtained in these sentence contexts reflects an automatic semantic processing of words that occurs even when semantic analysis is not required to complete a given task. The cooccurrence and topographical dissimilarity of the "N200" and N400 suggest that the N400 may not be a delayed or a generic N200.

Adolescent↗

PubMed1991

Mandibular ramus anatomy as it relates to the medial osteotomy of the sagittal split ramus osteotomy.

The sagittal split ramus osteotomy is probably the most frequently used procedure for correction of mandibular skeletal dentofacial deformities. Despite numerous improvements in the technique in the 30 years since the procedure was introduced, a number of troublesome complications still occur. These include unfavorable fracture during surgery, paresthesia, and relapse. The purpose of this study was to determine where fusion of the buccal and lingual cortical plates occurs in the upper mandibular ramus, as it is thought that placement of the horizontal medial osteotomy above the point of fusion (without any intervening medullary bone) may lead to unfavorable fracture during splitting. Forty-nine human mandibles were sectioned vertically at three locations perpendicular to the surface of the ramus and the occlusal plane. Measurements were made to locate vertically the point of fusion of the buccal and lingual cortical plates relative to the lingula and to the depth of the sigmoid notch. The point of fusion occurred between 7.5 and 13.3 mm above the lingula. Only 2% of mandibles had fusion at or below the level of the lingula in the anterior ramus, whereas in the posterior ramus, 6.1% of mandibles were fused at that level. At a level halfway from the lingula to the sigmoid notch, 20% of mandibles were fused in the anterior ramus, whereas in the mid- to posterior ramus, the incidence was as high as 39%. The location of the medial horizontal osteotomy should be at or just above the tip of the lingula. A higher level of cut may be associated with an increased difficulty in splitting or incidence of unfavorable fracture.

Humans↗

PubMedDate not supplied

How much explanation is enough? A study of parent requests for information and physician responses.

OBJECTIVE: To examine the relationship between doctor-parent communication patterns and parents' perceptions that they were listened to by the doctor. DESIGN: Cross-sectional, clinic-based survey. Before the visit, parents were asked about the strength of their desires/preferences for being listened to; after the visit, they were asked if their desires were fulfilled and to rate their satisfaction with care. Encounters were audiotaped, transcribed, and coded for parent requests for information and action and physician responses to those requests. Coding was performed using an adapted version of the Taxonomy of Requests by Patients (TORP). Physician responses to parental requests for information were coded as brief, moderate, or prolonged fulfillment or as partially fulfilled, ignored, or denied. SETTING: Two private pediatric practices, 1 community based and 1 university based. PARTICIPANTS: Ten of 13 eligible physicians (participation rate, 77%) and 306 of 356 eligible parents (participation rate, 86%) who sought care for their children's respiratory illnesses. Parents were invited to participate if they spoke and read English and if their child was 2-10 years old, had a chief complaint of cold symptoms, and was seeing one of the participating physicians. Complete data were obtained for 287 doctor-parent encounters (94%). RESULTS: Before the visit, 74% of parents reported that they considered it necessary for the physician to listen to their ideas about their child's illness. Among these parents, 62% (n = 130) reported after the visit that the physician had listened to their ideas. As the proportion of moderate-length responses to parent requests for information increased, parents were significantly more likely to report being listened to (P <.05). Multivariate results indicated a 59% probability of parents reporting that they were listened to when given moderate-length responses, 45% when given brief responses, 39% when given prolonged responses, and 12% when requests for information were only partially fulfilled, ignored, or denied. The length of response to parent requests for information was not related to overall parent satisfaction. CONCLUSIONS: Parents who received moderate-length answers to their questions were most likely to report that they were listened to. Although it is assumed that lengthier, in-depth explanations result in higher satisfaction, this study suggests that more doctor talk does not necessarily constitute better communication.

Adult↗

PubMedDate not supplied

Changes in blubber distribution and morphology associated with starvation in the harbor porpoise (Phocoena phocoena): evidence for regional differences in blubber structure and function.

To examine patterns of blubber loss accompanying a decline in body condition, blubber thickness of juvenile harbor porpoises in normal/robust body condition (n=69) was compared with that of starved conspecifics (n=31). Blubber thickness in the thorax of starved porpoises (9-11 mm) was only 50%-60% of that of normal animals (18-20 mm); however, very little tailstock blubber was lost during starvation. Adipocytes in thorax and tailstock blubber were measured in both groups (n=5) to determine whether thickness changes were homogeneous throughout blubber depth. In the thorax of normal porpoises, adipocytes near the epidermis (outer blubber) were smaller (0.11 nL) than inner blubber adipocytes (0.17 nL). Conversely, the size of tailstock adipocytes was uniform. Starved animals had fewer, smaller adipocytes in the inner thorax blubber, suggesting a possible combination of adipocyte shrinkage and loss. Lipids were withdrawn only from the inner layer of thorax blubber during starvation, supporting a hypothesis of regional specialization of function in blubber. Blubber of the thorax serves as the site of lipid deposition and mobilization, while the tailstock is metabolically inert and likely important in locomotion and streamlining. Therefore, some proportion of the blubber of small odontocetes must be considered structural/mechanical rather than an energy reserve.

Adipocytes↗

PubMed1990

Anorectal function in incontinent patients with cerebrospinal disease.

Anorectal manometry and the electrical activity of the external anal sphincter were measured in 20 patients with well-defined, incomplete spinal lesions who were referred because of fecal incontinence and in 30 normal subjects. Six patients had a high spinal lesion, 11 had a low spinal lesion, and 3 had mixed high and low spinal lesions. Patients with high spinal lesions had normal basal pressures but abnormally low squeeze pressures and impaired rectal sensation. Unlike normal subjects, there was no relationship between the depth of sphincter relaxation and the distention volumes. The external sphincter responses to rectal distention and increases in intraabdominal pressure were enhanced, and leakage of perfusion fluid was uncommon. Patients with low spinal lesions had abnormally low basal and squeeze pressures, blunted rectal sensation, and showed impaired external anal sphincter responses to rectal distention or increases in intraabdominal pressures. Most of these patients leaked the infused fluid during these maneuvers. Sphincter function in patients with mixed lesions was more severely impaired than in patients with low and high spinal lesions. Patients with mixed lesions showed abnormally low basal and squeeze pressures, impaired rectal sensation, and no external anal sphincter responses to either rectal distention or increases in intraabdominal pressure. Leakage occurred during these maneuvers in all patients with mixed lesions.

Adult↗

PubMed2005

Anterior chamber depth measurement with a-scan ultrasonography, Orbscan II, and IOLMaster.

PURPOSE: The authors conducted a comparison of anterior chamber depth (ACD) measurement by 3 devices of EchoScan, Orbscan II, and IOLMaster to assess the validity of the latter 2 and its reliability with Orbscan II. METHODS: Forty-four myopic patients, 56.8% female, were enrolled in this prospective study. In all 88 eyes, the ACD was first measured with Orbscan II, followed by IOLMaster and EchoScan U3300, both under cycloplegia. The mean (+/-standard deviation) age and spherical equivalent were 30.2+/-8.5 years and -4.98+/-2.67 D, respectively. The difference between ACD measurements by these 3 devices was analyzed using the repeated-measures analysis of variance. Agreement between each pair of devices was assessed by computing the 95% limits of agreement (LoA). Orbscan II reliability was also evaluated by using the 95% LoA between 2 consecutive measurements. P value adjustments for multiple comparisons were performed using the Bonferroni method. RESULTS: There was a statistically significant difference between measurements made with the 3 devices (p<0.001). The mean difference between Orbscan II and Echoscan ACD measurements was -0.03+/-0.12 mm, with the 95% LoA from -0.25 to +0.20 mm, and between IOLMaster and Echoscan measurements, it was +0.09+/-0.14 mm with the 95% LoA from -0.18 to +0.36 mm. On average, Orbscan II readings were lower and those of IOLMaster were higher than Echoscan readings. Both Orbscan II and IOLMaster agreed with Echoscan in measuring ACD. The 2 readings by Orbscan II had a 95% LoA of -0.05 and +0.07 mm that shows good reliability. CONCLUSION: ACD measurement differences with the 3 studied devices proved to be statistically significant; however, these minor differences may be clinically negligible depending on the use of the measurement. As an advantage, both Orbscan II and IOLMaster are noncontact, and with their ACD measurements being valid, they may be considered suitable devices for this purpose. In addition, Orbscan II produces highly repeatable ACD measurements.

Adult↗

PubMed2005

Is statistical significance always significant?

One way in which we learn new information is to read the medical literature. Whether or not we do primary research, it is important to be able to read literature in a critical fashion. A seemingly simple concept in reading is to interpret p values. For most of us, if we find a p value that is <.05, we take the conclusion to heart and quote it at every opportunity. If the p value is >.05, we discard the paper and look elsewhere for useful information. Unfortunately, this is too simplistic an approach. The real utility of p values is to consider them within the context of the experiment being performed. Defects in study design can make an interpretation of a p value useless. One has to be wary of type I (seeing a "statistically significant" difference just because of chance) and type II (failing to see a difference that really exists) errors. Examples of the former are publication bias and the performance of multiple analyses; the latter refers to a trial that is too small to demonstrate the difference. Finding significant differences in surrogate or intermediate endpoints may not help us. We need to know if those endpoints reflect the behavior of clinical endpoints. Selectively citing significant differences and disregarding studies that do not find them is inappropriate. Small differences, even if they are statistically significant, may require too much resource expenditure to be clinically useful. This article explores these problems in depth and attempts to put p values in the context of studies.

Clinical Trials as Topic↗

PubMed1993

Magnetic resonance imaging with Gadolinium-DTPA for assessment of bladder carcinoma and its response to treatment.

Magnetic Resonance Imaging (MRI) with intravenous Gadolinium-DTPA (Gd-DTPA, Magnevist, Schering-AG) was performed in 44 patients, 32 with primary bladder carcinoma and 12 with suspected recurrence after treatment. Gd-DTPA often increased diagnostic confidence in the identification and staging of tumours confined to the bladder wall and was necessary to assess depth of bladder wall invasion when T2-weighted images were suboptimal. Enhancement after Gd-DTPA enabled distinction between necrotic and viable tumour and blood clot. There was little advantage in its use for tumours infiltrating perivesical fat or with metastases to lymph nodes or bone, in the absence of a fat suppression sequence. Gd-DTPA may therefore be useful in selected patients with tumours of Stage T3a or less in whom information about depth of bladder wall invasion is inadequately shown on pre-contrast sequences. Artefacts due to variable and inhomogeneous urine signal intensity, however, often degraded post-Gd-DTPA images of the bladder. Changes in the bladder due to radiotherapy were observed on MRI 3-4 months after treatment in patients referred for routine follow-up and in some patients with suspected recurrence. Mucosal hyperintensity, thickening and abnormal signal intensity of the muscular layers of the bladder wall, with enhancement after Gd-DTPA were demonstrated. Such changes obscured small volume or superficial recurrence of tumour after radiotherapy. Abnormal enhancement was also observed in pelvic organs and soft tissues irradiated several years earlier. Enhancement after Gd-DTPA does not therefore reliably distinguish between recurrent tumour and radiotherapy change.

Aged↗

PubMed1997

Alcoholism at the time of injury among trauma center patients: vehicular crash victims compared with other patients.

A structured in-depth interview employing standardized criteria was used to determine the prevalence of lifetime and current alcohol dependence (alcoholism) in unselected consecutive patients admitted to a regional Level I trauma center. Of 629 patients, 157 (25.0%) were current alcoholics at the time of injury. An additional 87 (13.8%) were diagnosed as lifetime non-current alcoholics. There was no significant difference in the rates of current alcohol dependence among patients injured in vehicular crashes (23.5%), other unintentional trauma victims (29.3%), and those injured as a result of violence (24.6%). Of BAC+ (blood alcohol concentration positive) patients, 54.5% were current alcoholics. However, 14.4% of alcohol-negative patients were also diagnosed as alcohol dependent.

Accidents, Traffic↗

PubMed2004

Bacterial genomes as new gene homes: the genealogy of ORFans in E. coli.

Differences in gene repertoire among bacterial genomes are usually ascribed to gene loss or to lateral gene transfer from unrelated cellular organisms. However, most bacteria contain large numbers of ORFans, that is, annotated genes that are restricted to a particular genome and that possess no known homologs. The uniqueness of ORFans within a genome has precluded the use of a comparative approach to examine their function and evolution. However, by identifying sequences unique to monophyletic groups at increasing phylogenetic depths, we can make direct comparisons of the characteristics of ORFans of different ages in the Escherichia coli genome, and establish their functional status and evolutionary rates. Relative to the genes ancestral to gamma-Proteobacteria and to those genes distributed sporadically in other prokaryotic species, ORFans in the E. coli lineage are short, A+T rich, and evolve quickly. Moreover, most encode functional proteins. Based on these features, ORFans are not attributable to errors in gene annotation, limitations of current databases, or to failure of methods for detecting homology. Rather, ORFans in the genomes of free-living microorganisms apparently derive from bacteriophage and occasionally become established by assuming roles in key cellular functions.

AT Rich Sequence↗

PubMed2005

Cloning and molecular characterization of B-hordeins from Hordeum chilense (Roem. et Schult.).

One of the main limitations of cereal breeding is the lack of genetic variability within cultivated crops. Hordeum chilense is a wild relative of Hordeum vulgare, which has been successfully used in the synthesis of amphiploids by crossing with Triticum spp. Among the agronomic traits of these new amphiploids, the allelic variation in the endosperm storage proteins and their influence on breadmaking and malting quality are of special interest. B-hordeins are sulfur rich prolamins, which account for 70-80% of the total hordein fraction in barley. In this work, rapid amplification of cDNA ends by PCR (RACE-PCR) has been used for the cloning of the full-length open reading frame (ORF) of six sequences of B3-hordeins from two lines of H. chilense. Two consensus sequences of 813 and 822 bp for the H1 and H7 lines, respectively, were determined by alignment of all the sequences generated. Between both lines, differences involving single base changes, which could correspond to single nucleotide polymorphisms (SNP), insertions and deletions were observed. Of these differences, only six out of the 13 within the ORF caused a change of amino acid. Two insertions/deletions of 9 and 12 bp were also observed between both lines. The derived amino acid sequences showed a similar structure to the B-hordeins from cultivated barley and other prolamins. The repetitive region is based on the repetition of the motif PQQPFPQQ. The copy number of the B3-hordeins was estimated as a minimum of nine and five copies for the H1 and H7 lines, respectively. The expression profile of the B-hordeins through the developing endosperm is also described in this work. This study of the storage proteins of H. chilense is a useful contribution to the knowledge of the genetic diversity available in wild relatives of cultivated barley. In addition, the origin of the different prolamins can be better understood with an in-depth knowledge of its wild equivalent.

Amino Acid Motifs↗

PubMed2005

Neural correlates of intelligence as revealed by fMRI of fluid analogies.

It has been conjectured that the cognitive basis of intelligence is the ability to make fluid or creative analogical relationships between distantly related concepts or pieces of information (Hofstadter, D.R. 1995. Fluid Concepts and Creative Analogies. Basic Books, New York., Hofstadter, D.R. 2001. Analogy as the Core of Cognition. In The Analogical Mind: Perspectives from Cognitive Science (D. Gentner, K. J. Holyoak and B. N. Kokinov, Ed.). pp. 504-537. MIT Press, Cambridge, Mass.). We hypothesised that fluid analogy-making tasks would activate specific regions of frontal cortex that were common to those of previous inferential reasoning tasks. We report here a novel self-paced event-related fMRI study employed to investigate the neural correlates of intelligence associated with undertaking fluid letter string analogy tasks. Stimuli were adapted from items of the AI program Copycat (Mitchell, M. 1993. Analogy-making as Perception: A computer model. The MIT Press, Cambridge MA.). Twelve right-handed adults chose their own "best" completions from four plausible response choices to 55 fluid letter string analogies across a range of analogical depths. An analysis using covariates determined per subject by analogical depth revealed significant bilateral neural activations in the superior, inferior, and middle frontal gyri and in the anterior cingulate/paracingulate cortex. These frontal areas have been previously associated with reasoning tasks involving inductive syllogisms, syntactic hierarchies, and linguistic creativity. A higher-order analysis covarying participants' verbal intelligence measures found correlations with individual BOLD activation strengths in two ROIs within BA 9 and BA 45/46. This is a provocative result given that verbal intelligence is conceptualised as being a measure of crystallised intelligence, while analogy making is conceptualised as requiring fluid intelligence. The results therefore support the conjecture that fluid analogising could underpin general intellectual performance.

Adolescent↗

PubMed2006

Self-awareness and the subconscious effect of personal pronouns on word encoding: a magnetoencephalography (MEG) study.

The effect of personal pronouns such as "ein" (German for "a"), "mein" (German for "my") and "sein" (German for "his") on the processing of associated nouns was investigated using MEG. Three different encoding strategies were provided in order to vary the level of consciousness involved in verbal information processing. A shallow (alphabetic), a deep (semantic) and a very deep (contextual) encoding instruction related to visual word presentation were given to all study participants. After the encoding of pronoun-noun pairs, recognition performances of nouns only were tested. The number of correctly recognized nouns previously associated with "sein" was significantly lower than the number of correctly recognized nouns previously associated with "ein" in the shallow encoding condition. The same trend was found for "mein" associated nouns which were also less accurately recognized compared to "ein" associated nouns. Magnetic field distributions recorded during the encoding phases revealed two significant effects, one between about 200 and 400ms after stimulus onset and the other between about 500 and 800ms. The earlier effect was found over occipito-parietal sensors, whereas the later effect occurred over left frontal sensors. Within both time ranges, brain activation varied significantly as a function of associated pronoun independent of depth of word processing. In the respective areas of both time ranges, conditions including personal pronouns ("mein" and "sein") showed higher magnetic field components compared to the control condition of no personal pronouns ("ein"). Evidence is shown that early stage processing is able to distinguish between no personal and personal information, whereas later stage processing is able to distinguish between information related to oneself and to another person (self and non-self). Along with other previous reports our MEG findings support the notion that particular human brain functions involved in processing neurophysiological correlates of self and non-self can be identified.

Adult↗

PubMed2000

Effects of macroalgal mats on intertidal sandflats: an experimental study.

The growth of green macroalgal mats is becoming increasingly common in many marine intertidal habitats. While the ecological effects of such growth has previously been experimentally investigated on mudflats, such experiments have rarely been performed on intertidal sandflats. This study investigated the ecological effects of macroalgal cover on a moderately exposed intertidal sandflat, Drum Sands, Firth of Forth, Scotland. Artificially implanted Enteromorpha prolifera (Müller) caused marked changes in the macrobenthos, together with significant changes in all the measured sediment variables. After 6 weeks, the weed significantly increased the macrofaunal diversity. The numbers of Pygospio elegans (Claparède) were significantly reduced under weed mats, while those of Capitella capitata (Fabricius), oligochaetes and gammarids increased. Percent water, organics and silt/clay contents, medium phi and sorting coefficient significantly increased in the sediments under weed mats which also became significantly more reduced between 1 and 8 cm depth. After 20 weeks, a macrofaunal community numerically dominated by C. capitata, with a significantly reduced diversity, was present under weed mats, while sediment variables were no longer significantly different from controls. The negative effect of E. prolifera on P. elegans was mainly due to larval filtering, suggesting that weed is likely to have detrimental effects on population maintenance of most species which rely on planktonic larval recruitment. These results are broadly similar to those obtained from algal manipulation experiments performed in much more sheltered, muddier environments. We suggest that a predictable deterioration in environmental quality results from the growth of macroalgal mats in soft-bottom habitats. However, the longer term effects of such algal growth are less predictable and depend upon the spatial distributions of the most abundant infaunal species and the spatial heterogeneity of weed mat establishment.

Journal Article↗

PubMed2001

Large-scale forest girdling shows that current photosynthesis drives soil respiration.

The respiratory activities of plant roots, of their mycorrhizal fungi and of the free-living microbial heterotrophs (decomposers) in soils are significant components of the global carbon balance, but their relative contributions remain uncertain. To separate mycorrhizal root respiration from heterotrophic respiration in aboreal pine forest, we conducted a large-scale tree-girdling experiment, comprising 9 plots each containing about 120 trees. Tree-girdling involves stripping the stem bark to the depth of the current xylem at breast height terminating the supply of current photosynthates to roots and their mycorrhizal fungi without physically disturbing the delicate root-microbe-soil system. Here we report that girdling reduced soil respiration within 1-2 months by about 54% relative to respiration on ungirdled control plots, and that decreases of up to 37% were detected within 5 days. These values clearly show that the flux of current assimilates to roots is a key driver of soil respiration; they are conservative estimates of root respiration, however, because girdling increased the use of starch reserves in the roots. Our results indicate that models of soil respiration should incorporate measures of photosynthesis and of seasonal patterns of photosynthate allocation to roots.

Carbon↗

PubMed1997

Integrated mental health care: practitioners' perspectives.

OBJECTIVE: Integrated mental health care (IMHC) is a community-based model that considers the patient and informal carers to be the major contributors to stable recovery from severe mental health problems. This study investigates the implementation of IMHC by 35 New Zealand practitioners 1 year after being trained in the model. It also explores their experiences and perceptions regarding the model. METHOD: Quantitative and qualitative data were gathered by combining a questionnaire survey with in-depth interviews. RESULTS: Few of the trainees had been able to implement the model as much as they would have liked. A primary barrier to implementation was created by the resource constraints that impede most innovative community care initiatives even when demonstrated to be more cost-effective than traditional hospital-based approaches. Concerns particular to IMHC included issues relating to flexibility, time-intensiveness and applicability to New Zealand. Many practitioners found some of the specific intervention strategies and the clear overall structure of the model useful. Its psychosocial emphasis had a positive impact on many practitioners' beliefs about the causes and prognosis of severe mental health problems. CONCLUSIONS: Participants offer a range of recommendations as to how IMHC might be applied and adapted. Consultation with staff, consumers, families and Maori, as well as a strengthening of the psychosocial components, are recommended.

Attitude of Health Personnel↗

PubMed2002

Hemispheric encoding asymmetry is more apparent than real.

Previous neuroimaging studies have claimed a left hemisphere specialization for episodic "encoding" and a right hemisphere specialization for episodic "retrieval." Yet studies of split-brain patients indicate relatively minor memory impairment after disconnection of the two hemispheres. This suggests that both hemispheres are capable of encoding and retrieval. In the present experiment, we examined the possible limits on encoding capacity of each hemisphere by manipulating the "depth" of processing during the encoding of unfamiliar faces and familiar words in the left and right hemispheres of two split-brain patients. Results showed that only the left hemisphere benefited from deeper (more elaborate) encoding of familiar words, and only the right hemisphere benefited from deeper encoding of unfamiliar faces. Our findings are consistent with the view that hemispheric asymmetries in episodic encoding are related to hemisphere-specific processing of particular stimuli. Convergent with recent neuroimaging studies, these results with split-brain patients also suggest that these hemispheric differences are not due to unique specializations in each half brain for encoding memories, but rather, are due to preferential recruitment of the synaptically closer prefrontal cortex to posterior regions processing material-specific information.

Adolescent↗

PubMed2004

Accuracy and reproducibility of two manual periodontal probes. An in vitro study.

BACKGROUND: Periodontal probe is the standard instrument for assessment of probing pocket depth and clinical attachment level. However, probing measurements have inherent measurement errors from a wide range of sources, such as instrument, patient, examiner and disease status. AIM: The purpose of the present study was to create an in vitro model simulating gingival sulcus/pocket and investigate the accuracy and reproducibility of two different manual probes. METHODS: Thirty-three aluminium blocks with dimensions of 2 x 2 cm and thickness ranging from 2.00 to 10.00 mm were constructed. Holes with a diameter of 1.00 mm were made in the blocks through the whole thickness. These 33 aluminium blocks were then carefully stuck together so that the probing faces would be on the same level. A plastic material, which shows deformation with forces >45 g was placed at the base of the blocks. Two conventional manual probes (Williams and WHO probes) were used in the present study. Seventeen periodontists were selected to perform duplicate measurements on the blocks over two visits using both of the probes. The intra- and inter-examiner percentage accuracy (with regard to 0.25 mm) and reproducibility for each of the duplicate measurements was calculated and analysed using repeated measure analysis of variance (ANOVA) (three factor experiments with repeated measure on two factors; probe and probing session). RESULTS: ANOVA showed statistically significant differences between the examiners (p=0.000) and between the two readings of each probe (p=0.002), while the differences between the two probes were not statistically significant (p=0.098). The overall percentage of accuracy was higher with WHO probe compared with Williams probe. Kappa analysis revealed better reproducibility percentages for WHO probe in comparison with Williams probe. CONCLUSIONS: This in vitro study, using a metal construction and a plastic material with a deformation coefficient similar to that of gingival pocket, may be suggested as a good model to test intra- and inter-examiner differences in periodontal probing. Our findings emphasise the importance of inter-examiner calibration for probing, particularly in longitudinal studies.

Adult↗