Maximal bite force and bruxism

were obtained, and PCR tests were run and used universal bacterial primers that target the 16S ribosomal RNA gene present in most bacteria. Results.—After the periodontal probing, 6 subjects had positive cultures, including the following organisms: Propionibacterium acnes, Neisseria pharyngis, Streptococcus viridans, Micrococcus spp, Staphylococcus albus, P intermedia, Actinomyces naeslundii, Haemophilus aphrophilus, and coagulase-negative Staphylococcus species. Gemella haemolysans was found in 1 subject after toothbrushing. Three subjects had positive cultures after ultrasonic scaling. PCR testing indicated that 3 samples were positive after visit 1, 1 after visit 2, 5 after periodontal probing, 4 after toothbrushing, and 7 after ultrasonic scaling. The PCR data indicated a trend toward more positive cultures related to deeper pockets, but the small subject sample did not translate to statistical significance. The rates of bacteremia ranged from 13% to 20%. Discussion.—Periodontal probing, toothbrushing, and ultrasonic scaling can produce bacteremia that is detectable. However, the rates of bacteremia reported were

lower than those noted in previous studies. It is possible that patients who have adult periodontitis have immune systems that are able to cope with periodontal bacteria and quickly and efficiently clear the bacteria from the patient’s system.

Clinical Significance.—Transient bacteremias have long been known to follow dental manipulations, such as routine prophylaxis, and have been implicated etiologically in bacterial endocarditis in susceptible subjects. In this study, the level of bacteremia produced was lower than commonly anticipated. What effect this finding has clinically needs further study.

Kinane DF, Riggio MP, Walker KF, et al: Bacteraemia following periodontal procedures. J Clin Periodontol 32:708-713, 2005 Reprints available from DF Kinane, Univ of Louisville School of Dentistry, Research and Enterprise, Louisville, KY 40292; e-mail: [email protected]

Occlusion Maximal bite force and bruxism Background.—The involuntary clenching and/or grinding of the teeth characteristic of bruxism does not have a functional objective. Dental clenching is more common in diurnal bruxism, whereas both clenching and grinding occur in nocturnal bruxism. This parafunctional activity has been linked to occlusal problems, stress, altered central nervous system status, sleep disorders, and certain medications. Both the activity and the volume of the masticatory muscles are increased, but the effect of these changes on

108 Dental Abstracts

bite force has not been well evaluated. The relationship between voluntary maximal bite force (MBF) and presence of bruxism was assessed. Methods.—Forty men and 40 women age 20 to 38 years who were dentate participated. The MBF was determined with use of a compressive load transducer at the first molar region. Patients self-reported the presence of centric or eccentric bruxism during the day or at night or were diag-

Table 2.—Maximal Bite Force (N) of Bruxers and Nonbruxers as a Function of Sex Maximal Bite Force (N) Mean

Men Bruxism No Yes Overall Women Bruxism No Yes Overall All subjects Bruxism No Yes Overall

SD

n

1019a 991a 1009a

298 284 290

26 14 40

678b 653b 668b

189 168 179

23 17 40

859a 806a 838a

304 282 295

49 31 80

Note: Means followed by different letters (a,b) are statistically different at the 0.5 level of significance. (Courtesy of Cosme DC, Baldisserotto SM, de Andrade Canabarro S, et al: Bruxism and voluntary maximal bite force in young dentate adults. Int J Prosthodont 18:328-332, 2005.)

nosed on the basis of tooth wear. In assessing MBF, bruxism and gender were the fixed factors and body mass index and orofacial muscular pain were covariates.

cally significant factor in predicting MBF, with men having a higher MBF than women. Body mass index was not a significant factor in determining MBF, nor was orofacial muscular pain. Discussion.—Voluntary MBF did not differ between subjects with bruxism and those without this parafunction. Bruxers did have mild to moderate tooth wear in the occlusal and incisal tooth surfaces, which was not present in nonbruxers.

Clinical Significance.—Interestingly, in this study, no difference was found between the maximal bite force of bruxers and nonbruxers. It has been suggested bruxers bite harder, possibly due to masticatory muscles being overdeveloped, either naturally or as a result of function.

Cosme DC, Baldisserotto SM, de Andrade Canabarro S, et al: Bruxism and voluntary maximal bite force in young dentate adults. Int J Prosthodont 18:328-332, 2005 Reprints available from DC Cosme, Dept of Prosthodontics, Pontifical Catholic Univ of Rio Grande do Sul (PUCRS), Av José Aluísio Filho 889, Casa 97, Humaitá, Porto Alegre/RS, Brazil 90250-180; fax: +5551 33203626; e-mail: [email protected]

Results.—The bruxers and nonbruxers exhibited equivalent degrees of MBF (Table 2). Gender was a statisti-

Operative Dentistry Poor retention without surface preparation Background.—The dentinal surfaces of noncarious cervical lesions are often hypermineralized and resist acid etching. As a result, resin composites show reduced efficacy in bonding to this type of dentin, leading some to rec-

ommend mechanical removal of the surface or more aggressive etching. When nonretentive Class V resin restorations are used for unabraded lesions and retained with use of 2-bottle (dentin-adhesive resins) adhesives, the reten-

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