Can nonstandardized bitewing radiographs be used to assess the presence of alveolar bone loss in epidemiologic studies?

OBJECTIVE: To compare periodontitis-associated alveolar bone loss assessment by standardized and nonstandardized radiographs in clinical and epidemiologic studies. METHODS: Participants included 37 patients aged 21-66 years with prior nonstandardized bitewing radiographs scheduled to receive bitewing radiographs as part of their next routine dental care visit. Standardized bitewing radiographs were taken with a Rinn film holder to position the film in the mouth and align the X-rays so that they were at 90 degrees to the film. Before taking the radiograph the bite was registered in centric relation using a polyether impression material. One registered dental hygienist took and processed all the standardized radiographs. One dentist read all radiographs using a viewing box, magnifying lens, and periodontal probe with William's markings. Radiographic bone loss was measured to the closest millimeter at mesial and distal sites of the posterior teeth excluding third molars. The examining dentist was blinded to the participant's name, age, gender, or if the radiograph was standardized or nonstandardized. RESULTS: Mean bone loss (+/- SD) was similar in the standardized and nonstandardized groups (1.60 +/- 0.72 mm versus 1.64 +/- 0.85 mm), and the correlation was high (r = 0.95). Periodontitis was defined as present if the participant had at least one site with 3, 4 and 5 mm bone loss. The Kappa statistics for concordance using these three cutoffs were good and ranged from 0.60 to 0.65. The sensitivity ranged from 72.7 to 80.8% and specificity from 88.5 to 90.9%. CONCLUSIONS: Periodontitis assessed as mean alveolar bone loss or the prevalence of disease based on alveolar bone loss can be accurately and reliably evaluated from nonstandardized radiographs.     

An examination of the surface corrosion state of dental fillings and constructions

A group of 115 patients with orofacial complaints has been examined. A new method for intraoral measurement of electrode potentials on the surface of the amalgam fillings and prosthetic constructions has been developed and applied. The possible connections between the measured electrode potentials and patients' saliva properties and their complaints have been discussed. No correlations between measured electrode potentials of the metallic fillings and constructions and important saliva properties could be found. No connections between the measured electrode potentials and the patients' complaints could be proved.     

Reflex activity in the masseter muscle of young individuals

The monosynaptic myotatic (jaw jerk) potential (MSP) evoked in the relaxed masseter by a tap on the chin and recorded electromyographically in this muscle (latency 6-3 ms, duration 5-9 ms) was similar in subjects with, or without TMJ clicking. The latency of the myotatic potential was significantly shorter (5.8 ms) when evoked during isometric contraction. The duration was 5-2 ms. A potential with similar characteristics as the MSP was evoked by TMJ clicking, as we believe by excitation of muscle spindles from tissue transmitted vibrations (latency 5-5 ms, duration 5-6 ms). The TMJ click evoked MSP could in the contracting massester be followed by silent periods (SPs) both of the early (latency about 10 ms) and the late type (latency about 50 ms). A tap on the chin during isometric contraction of the jaw elevators, was followed by an SP of the early type (latency 12-2 ms, duration 17-5 ms) and sometimes by an SP of the late type (latency 58 ms, duration 18 ms). The late SP occurred significantly more often in patients with TMJ-dysfunction. The period of lower activity following an MSP can be divided into two phases: a first phase with a complete electrical silence, denoted SP, and a second phase during which the activity is slowly increasing to reach the control level. This latter phase will be called "depressed activity" (DA) and is introduced as a new parameter. The SP with tooth tapping (latency 10-5 ms, duration 9-4 ms) was similar in groups with or without TMJ clicking. The superimposed MSP (SMSP) preceding the SP at tooth tapping is supposed to be a manifestation of the "load-compensation reflex".     

Salivary flow, saliva, pH and buffering capacity in 70-year-old men and women

A representative systematic selection of 30% of all 70-year-olds (1148 persons) in Göteborg were invited to a population study. The participation rate was 85%. Sixteen per cent of the men and 25% of the women reported dryness in the mouth (sex. diff. P<0.01). There was a significant correlation between the number of drugs consumed by the subjects and subjective dryness (in both sexes P<0.001). Intake of drugs from the groups of anticholionergics, antihistamines, sedatives, hypnotics or phenothiazines respectively seemed to have the highest predicative value for dryness in the mouth (men P<0.05 and women P<0.01). There was also a positive correlation between subjective dryness and number of definable diseases in both sexes (P<0.01). In a consecutive sample (fifty-eight men and fifty-three women) a study of salivary flow, direct pH and buffer effect were performed. The mean value of unstimulated salivary secretion was in men 0.25 and in women 0.18ml/min. Corresponding figures for stimulated secretion was 1.65 and 1.04ml/min (sex. diff. P<0.01). A significantly lower unstimulated secretion was noted in women with subjective dryness (P<0.01). A negative significant correlation were found between dental invalidity, according to Eichner's classification, and stimulated secretion when drug treatment had been considered (men P<0.05 and women P<0.01). Only weak relations were noted between salivary secretions and drug treatment. Only intake of drugs with diuretic effect were negatively correlated to stimulated secretion (P<0.01). Diseases of the circulatory system were correlated to subjective dryness (P<0.01).