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Jaw muscle strength and dentures
Among children aged 6 to 11 years, who have a mixed dentition, caries experience was unchanged overall, with no significant alterations in the broad categories of poor or non-poor children. However, poor non-Hispanic black children had an increase from 51% to 68% and non-poor Mexican-American children an increase from 52% to 68%. Untreated caries prevalence was not changed for children aged 6 to 11 years, but poor Mexican-American children experienced a decline in untreated dental decay in those aged 6 to 11 years (51% to 42%) and 6 to 8 years (57% to 44%). Among non-poor Mexican-American children an increase in untreated decay from 20% to 32% occurred. Severe decay among poor children fell from 33% to 27%, but its prevalence was unchanged for near-poor and non-poor children aged 6 to 11 years. The prevalence did not change significantly for poor girls of this age, but it did for boys. The mean dfs-DFS (decayed filled surfaces in primarypermanent dentition) increased significantly overall and specifically in the mesiodistal surfaces for poor and nearpoor children, and also the buccal and lingual surfaces for near-poor children. A significant decline in dental caries experience of the permanent dentition was noted among all children aged 6 to 11 years (25% to 21%), with notable changes among all non-poor children (22% to 16%) and all boys (23% to 19%). However, the experience was unchanged for all poor children aged 6 to 11 years. Non-Hispanic white children aged 6 to 11 years had a significant decline in caries experience (24% to 19%), but poor non-Hispanic white children had an increase (24% to 30%). Poor Mexican-American children aged 9 to 11 years showed a significant increase in dental caries from 38% to 55%. No change was noted in the prevalence of untreated caries of the permanent dentition for children aged 6 to 11 years.
The overall mean DFS for total dental surfaces declined significantly for all children this age. Discussion.—Overall these findings indicate that the increase in dental caries of the primary dentition affects boys at a higher rate than girls. Untreated disease also has significantly increased for boys compared to girls. With respect to the permanent dentition, dental caries is either declining or remaining unchanged for most children, but shows disparate findings among MexicanAmerican children, increasing among the non-poor and declining among the poor. The explanation for increased caries prevalence among children appears to relate to unhealthy eating habits and inadequate dental insurance coverage.
Clinical Significance.—Among our pediatric patients, dental caries appears to be disproportionately affecting boys compared to girls. Even among non-poor children, primary caries is increasing in high-risk groups. This increase indicates that changes in eating habits or dental care coverage are occurring. The potential is for poorer oral health status in the future and greater demand for dental services, especially among underserved populations.
Dye BA, Arevalo O, Vargas CM: Trends in paediatric dental caries by poverty status in the United States, 1988 1994 and 1999 2004. Int J Paediatr Dent 20:132-143, 2010 Reprints available from B Dye, CDC/NCHS/NHANES Programme, 3311 Toledo Rd, Rm 4416, Hyattsville, MD 20782; e-mail: [email protected]
Prosthodontics Jaw muscle strength and dentures Background.—Conventional denture wearers have lower maximum bite force values than dentate subjects and thus are less able to break down food during chewing and clenching. However, the strengths of the jaw muscles between dentate persons and denture wearers have not been determined previously. Methods.—Three groups were compared with respect to maximum bite forces, electromyographic (EMG) activity,
and estimated jaw muscle strength: (1) 17 edentulous subjects using newly fitted implant-retained overdentures (mean age, 60.3 years); (2) 10 age-matched subjects with full dentition (mean age, 57.9 years); and (3) 39 young (mean age, 24.4 years) fully dentate subjects. The EMG readings were obtained from the bilateral superficial masseter and anterior temporalis muscles while they generated maximum voluntary bite forces at the right central incisor, right first premolar, and right first molar positions. The ratio
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Results.—The maximum bite force for the denture wearers was significantly lower than for the dentate subjects (Fig 1), measuring less than half of the values for the other two groups. The dentate groups had similar maximum bite force readings. During maximum biting, denture wearers employed significantly less EMG activity than the dentate groups except during premolar biting by the young dentate subjects. The EMG/Force ratios were significantly higher for denture wearers than for the dentate subjects. The young dentate subjects had significantly lower EMG/Force ratios than the older dentate subjects during incisor and molar biting. Younger subjects produced the same force using less muscular effort. Discussion.—It appears that when denture wearers first receive their implant-retained dentures, their jaw muscles are weaker than those of dentate subjects. The weakness may result from chronic underuse related to wearing unstable dentures. Lower bite force may reflect the combination of unstable dentures and weaker jaw muscles. It is expected that maximum bite forces will increase and EMG activity will decrease, as the denture wearers grow more accustomed to their stable dentures.
Fig 1.—Comparison of maximum bite forces (A), muscle activity levels (B), and electromyographic/Force ratios (C) among patients with complete denture at the initial loading of their mandibular implants, age-matched dentate subjects, and young dentate adults. Abbreviations: I, Incisor bite position; P, premolar bite position; M, molar bite position. )Significant difference between denture wearers and dentate subjects. &, Significant difference between age-matched and young dentate subjects. (Courtesy of Caloss R, Al-Arab M, Finn RA, et al: Does long-term use of unstable dentures weaken jaw muscles? J Oral Rehab 37:256-261, 2010.)
of the average EMG activity for all four muscles to the maximum bite force provided an estimate of jaw muscle strength.
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Dental Abstracts
Clinical Significance.—We have known for a long time that traditional, mucosasupported denture wearers have lower maximum voluntary occlusal forces than persons with a complete natural dentition. This does not necessarily mean that they have weaker jaw muscles, so it was important to evaluate the situation carefully. The combination of unstable dentures and underused jaw muscles adequately explains why denture wearers have weaker muscle strength. Changing to an implant-supported denture increases the stability and should allow the denture wearer to use the jaw muscles appropriately. Studies are still needed to determine whether the weaker muscles actually become stronger with implant-supported dentures.
Caloss R, Al-Arab M, Finn RA, et al: Does long-term use of unstable dentures weaken jaw muscles? J Oral Rehab 37:256-261, 2010 Reprints available from GS Throckmorton, Dept of Cell Biology, Univ of Texas Southwestern Medical Ctr at Dallas, 5323 Harry Hines Blvd, Dallas, TX 75390-9039; e-mail: Gaylord.Throckmorton @UTSouthwestern.edu
The overall mean DFS for total dental surfaces declined significantly for all children this age. Discussion.—Overall these findings indicate that the increase in dental caries of the primary dentition affects boys at a higher rate than girls. Untreated disease also has significantly increased for boys compared to girls. With respect to the permanent dentition, dental caries is either declining or remaining unchanged for most children, but shows disparate findings among MexicanAmerican children, increasing among the non-poor and declining among the poor. The explanation for increased caries prevalence among children appears to relate to unhealthy eating habits and inadequate dental insurance coverage.
Clinical Significance.—Among our pediatric patients, dental caries appears to be disproportionately affecting boys compared to girls. Even among non-poor children, primary caries is increasing in high-risk groups. This increase indicates that changes in eating habits or dental care coverage are occurring. The potential is for poorer oral health status in the future and greater demand for dental services, especially among underserved populations.
Dye BA, Arevalo O, Vargas CM: Trends in paediatric dental caries by poverty status in the United States, 1988 1994 and 1999 2004. Int J Paediatr Dent 20:132-143, 2010 Reprints available from B Dye, CDC/NCHS/NHANES Programme, 3311 Toledo Rd, Rm 4416, Hyattsville, MD 20782; e-mail: [email protected]
Prosthodontics Jaw muscle strength and dentures Background.—Conventional denture wearers have lower maximum bite force values than dentate subjects and thus are less able to break down food during chewing and clenching. However, the strengths of the jaw muscles between dentate persons and denture wearers have not been determined previously. Methods.—Three groups were compared with respect to maximum bite forces, electromyographic (EMG) activity,
and estimated jaw muscle strength: (1) 17 edentulous subjects using newly fitted implant-retained overdentures (mean age, 60.3 years); (2) 10 age-matched subjects with full dentition (mean age, 57.9 years); and (3) 39 young (mean age, 24.4 years) fully dentate subjects. The EMG readings were obtained from the bilateral superficial masseter and anterior temporalis muscles while they generated maximum voluntary bite forces at the right central incisor, right first premolar, and right first molar positions. The ratio
Volume 55
Issue 4
2010
221
Results.—The maximum bite force for the denture wearers was significantly lower than for the dentate subjects (Fig 1), measuring less than half of the values for the other two groups. The dentate groups had similar maximum bite force readings. During maximum biting, denture wearers employed significantly less EMG activity than the dentate groups except during premolar biting by the young dentate subjects. The EMG/Force ratios were significantly higher for denture wearers than for the dentate subjects. The young dentate subjects had significantly lower EMG/Force ratios than the older dentate subjects during incisor and molar biting. Younger subjects produced the same force using less muscular effort. Discussion.—It appears that when denture wearers first receive their implant-retained dentures, their jaw muscles are weaker than those of dentate subjects. The weakness may result from chronic underuse related to wearing unstable dentures. Lower bite force may reflect the combination of unstable dentures and weaker jaw muscles. It is expected that maximum bite forces will increase and EMG activity will decrease, as the denture wearers grow more accustomed to their stable dentures.
Fig 1.—Comparison of maximum bite forces (A), muscle activity levels (B), and electromyographic/Force ratios (C) among patients with complete denture at the initial loading of their mandibular implants, age-matched dentate subjects, and young dentate adults. Abbreviations: I, Incisor bite position; P, premolar bite position; M, molar bite position. )Significant difference between denture wearers and dentate subjects. &, Significant difference between age-matched and young dentate subjects. (Courtesy of Caloss R, Al-Arab M, Finn RA, et al: Does long-term use of unstable dentures weaken jaw muscles? J Oral Rehab 37:256-261, 2010.)
of the average EMG activity for all four muscles to the maximum bite force provided an estimate of jaw muscle strength.
222
Dental Abstracts
Clinical Significance.—We have known for a long time that traditional, mucosasupported denture wearers have lower maximum voluntary occlusal forces than persons with a complete natural dentition. This does not necessarily mean that they have weaker jaw muscles, so it was important to evaluate the situation carefully. The combination of unstable dentures and underused jaw muscles adequately explains why denture wearers have weaker muscle strength. Changing to an implant-supported denture increases the stability and should allow the denture wearer to use the jaw muscles appropriately. Studies are still needed to determine whether the weaker muscles actually become stronger with implant-supported dentures.
Caloss R, Al-Arab M, Finn RA, et al: Does long-term use of unstable dentures weaken jaw muscles? J Oral Rehab 37:256-261, 2010 Reprints available from GS Throckmorton, Dept of Cell Biology, Univ of Texas Southwestern Medical Ctr at Dallas, 5323 Harry Hines Blvd, Dallas, TX 75390-9039; e-mail: Gaylord.Throckmorton @UTSouthwestern.edu