Oral comfort in shortened dental arches

In this study, the oral comfort was compared between subjects with shortened dental arches (SDA, n = 74), subjects with SDA and free-end removable partial dentures (SDA + RPD, n = 25) and subjects with complete dental arches (CDA, n = 72). Oral comfort was measured by (i) absence of pain or distress; (ii) chewing ability; (iii) appreciation of the appearance of the dentition. Additionally, the history of free-end RPD over a period of nearly 7 years was taken into consideration. On the whole, the results did not reveal any significant differences between the three groups with respect to pain or distress. Only 8% of the subjects with SDA reported impairment of chewing ability, and 11% had aesthetic complaints, due to missing posterior teeth in the upper jaw. Of the subjects with SDA + RPD, 20% had complaints about the RPD. In addition, the repeated necessity for repair or replacement of free-end RPD and the fact that some subjects (20%) stopped wearing the RPD during the observation period, confirm the poor performance of this dental provision. It is concluded that the oral comfort of subjects with SDA in this study is compromised to a small extent but remains on an acceptable level. Free-end RPDs do not appear to help oral comfort in these cases.     

A 6-year follow-up study of oral function in shortened dental arches. Part II: Craniomandibular dysfunction and oral comfort*

In this clinical 6-year follow-up study subjects with shortened dental arches (SDA, n= 55), characterized by the absence of molar support, are compared with subjects with complete dental arches (CDA, n= 52) with respect to items concerning craniomandibular dysfunction and oral comfort. In addition, a small group of subjects with SDA and removable partial dentures in the lower jaw (SDA + RPD, n=19) is included in this study. Oral comfort is defined using the following criteria: (i) absence of pain and distress, meaning the absence of signs and symptoms of craniomandibular dysfunction; (ii) chewing ability; and (iii) appreciation of the appearance of the dentition in relation to absent posterior teeth. Additionally, complaints about the free-end RPD are described. It is concluded that: (i) a SDA (consisting of 3–5 occlusal units, OU) is not a risk factor for CMD and is able to provide long-term sufficient oral comfort; and (ii) free-end RPD (in the lower jaw) in SDA do not prevent CMD and do not improve oral function in terms of oral comfort.     

Shortened dental arches and periodontal support.

The periodontal support of subjects with shortened dental arches (SDA, n = 74), and of subjects with SDA and free-end removable partial dentures in the lower jaw (SDA and RPD, n = 25) was compared with that of subjects with complete dental arches (CDA, n = 72). The periodontal support was determined by tooth mobility and alveolar bone height, measured on a radiograph, of the distal alveolar bone of the premolars. Significant differences in tooth mobility were found between the three groups of subjects. The relative bone height showed a trend towards lower values for the SDA group and the SDA and RPD group. For some teeth these differences were significant. Premolars that are the most posteriorly located occluding teeth in the dental arch tend to have a lower relative alveolar bone height than premolars in an intermediate location. This effect is more marked in the upper jaw than in the lower jaw. Premolars in the lower jaw, that serve as abutment teeth for free-end RPDs, tend to show lower values for the relative bone height. It is concluded that the differences between the three groups with regard to the periodontal support are small. The large amount of crowns and bridges in both the SDA and SDA and RPD groups, and the dental history of these subjects, resulting in SDA, should be taken into account. However, as indicated by the periodontal breakdown of premolars in some subjects with SDA, the combination of an existing severe periodontal involvement and a SDA is considered to be an unfavourable situation.     

A 6-year follow-up study of oral function in shortened dental arches. Part I: Occlusal stability

In this clinical 6-year follow-up study subjects with shortened dental arches (SDA, n = 55), characterized by the absence of molar support, are compared with subjects with complete dental arches (CDA, n = 52) with respect to occlusal stability. In addition, a small group of subjects with SDA and removable partial dentures in the lower jaw (SDA + RPD, n = 19) is included in this study. The aim of this study was to describe effects regarding occlusal stability in subjects with SDA during a 6-year period. The applied parameters for occlusal stability are: number of occlusal contacts in the anterior region, overbite, interdental spacing and alveolar bone support.
The results of this study show that: (i) SDA do provide durable occlusal stability; (ii) free-end RPD do not contribute to occlusal stability in SDA; and (iii) SDA with periodontally involved teeth show continuing periodontal breakdown.     

Social and functional impact of reduced posterior dental units in older adults

The number of teeth needed to maintain adequate dental function in older adults is unknown. The purpose of this study was to examine the relationship between oral function and the number of opposing pairs of posterior teeth. We identified 338 subjects with complete anterior dentitions from an interview and examination survey of Ontario adults aged 50 and over; 261 had no partial denture and 77 had removable partial dentures (RPD). Oral function was measured using questions assessing chewing ability, mandibular function and socio-psychological impact.
Subjects with no partial dentures were further allocated to five groups, based on their dental status: complete dental arch ( n = 69); 5–7 functional units-pairs of opposing posterior teeth ( n = 109); 3 or 4 functional units ( n = 48) and 0–2 functional units ( n = 35). Oral function problems increased with decreasing functional units being markedly more prevalent among the groups with 0–2 functional units. 34% of subjects in the 0–2 group reported one or more problems with chewing ability compared to 6–17% in the other groups (χ² P = 0.001 d.f. = 3).
The 77 subjects who wore removable partial dentures, reported social and dental function at levels comparable to those with no dentures.
From these results, there appears to be little socio-functional need to replace lost posterior teeth with a partial denture until the person has fewer than, 3 posterior functional units. The low number of partial denture wearers limited our ability to detect a lasting benefit from RPD treatment.     

Chewing with shortened dental arches

Masticatory performance as measured with (objective) chewing tests is correlated with the number of teeth (the food platform area). In general, however, the masticatory ability (the subjective chewing experience) is sufficient as long as 20 or more 'well-distributed' teeth remain, such as is the case with an SDA, when the anterior teeth and the premolar teeth are present. Research indicates that an SDA does not lead to altered food selection. Studies have shown that a free-end removable partial denture generally does not improve the oral function in terms of masticatory ability or chewing comfort, unless in case of extreme shortened dental arches with only the anterior teeth present.     

Migration of teeth in shortened dental arches

In shortened dental arches (SDA) the remaining premolars tend to migrate distally. This may lead to a decrease of the vertical dimension, resulting in an increased load on the anterior teeth. Consequently the number and intensity of the occlusal contacts between the front teeth increase. This may result in interdental spacing in the upper front region. In this study the pattern of migration of the teeth in subjects with SDA (n = 60) is described. The SDA group is compared with subjects having complete dental arches (n = 72). Although a systemic effect of SDA has been found on interdental spacing for subjects under 40 years of age, it is concluded that this migration is within acceptable levels.     

The relationship between missing occlusal units and oral health-related quality of life in SDA patients

The aim of this multi-center study was to explore the relationship between missing occlusal units and oral health-related quality of life (OHRQoL) in subjects with the shortened dental arches (SDAs). Subjects with SDAs were recruited consecutively for one month from six university-based prosthodontic clinics. In total, 115 SDA subjects participated (mean age, 58.5 +/- 10.0 yrs; 71% female). The location and number of missing teeth were examined and the number of missing occlusal units was calculated. To evaluate OHRQoL, the Japanese version of the Oral Health Impact Profile (OHIP-J) was administered and the summary score of OHIP-J was calculated. The SDA subjects were categorized depending upon the anterior-posterior lengths of the missing or remaining occlusal units. Regression analyses were performed to investigate 1) the association between missing OU and OHIP-J summary scores and 2) the OHIP-J differences between groups of subjects with various anterior-posterior SDA lengths. The first analyses revealed that one missing OU was significantly related to an increase of 2.1 OHIP-J units (95% CI: 0.6-3.5, P=0.016). The second analysis revealed that subjects who only lost the second molar contact exhibited significantly better OHRQoL than those who lost more teeth (Coefficient: 11.1, 95% CI: 2.8-19.2, P=0.02). Furthermore a statistically significant group difference was observed between the groups with and without the first molar occlusal contact (Coefficient: 12.8, 95% CI: 1.4 to 24.1, P=0.03). These results suggest that missing occlusal units are related to the OHRQoL impairment in subjects with SDAs. They also suggest that the patterns of missing occlusal units are likely to be related to the OHRQoL impairment in SDA subjects with the presence of first molar contact having an important role.     

Mastication in subjects with extremely shortened dental arches rehabilitated with removable partial dentures

Mastication was evaluated in subjects presenting extremely shortened dental arches (ESDAs) rehabilitated with mandibular free-end removable partial dentures (RPDs). Subjects were divided into four groups (n = 10): those with a complete dentition, those with ESDAs, and those with ESDAs who were rehabilitated with an RPD, who were evaluated both with and without their prostheses. Mastication was measured through masticatory performance, time, and ability. RPD wearers showed higher masticatory performance (P < .01) and ability (P < .001) and lower masticatory time (P < .001) than when not wearing their prostheses as well as ESDA subjects who had not received RPD therapy. Those with a complete dentition showed the best results (P < .001). It can be suggested that RPDs improve mastication in ESDA subjects but without achieving normal mastication levels.     

An observational cohort study on shortened dental arches—clinical course during a period of 27–35 years

Objectives

The objective of this study was to investigate the clinical course of shortened dental arches (‘SDA group’) compared to SDAs plus removable denture prosthesis (‘SDA plus RDP group’) and complete dental arches (‘CDA group’, controls).

Materials and methods

Data (numbers of direct and indirect restorations, endodontic treatments, tooth loss and tooth replacements) were extracted from patient records of subjects attending the Nijmegen Dental School who previously participated in a cohort study on shortened dental arches with three to four posterior occluding pairs (POPs).

Results

Records of 35 % of the original cohort were retrievable. At the end of the follow-up (27.4?±?7.1 years), 20 out of 23 SDA subjects still had SDA with 3–4 POPs compared to 6 out of 13 for SDA plus RDP subjects (follow-up 32.6?±?7.3 years). Sixteen out of 23 CDA subjects still had CDA; none of them lost more than one POP (follow-up 35.0?±?5.6 years). SDA group lost 67 teeth: 16 were not replaced, 16 were replaced by FDP and 35 teeth (lost in three subjects) replaced by RDP. Mean number of treatments per year in SDA subjects differed not significantly compared to CDA subjects except for indirect restorations in the upper jaw.

Conclusion

Shortened dental arches can last for 27 years and over. Clinical course in SDA plus RDP is unfavourable, especially when RDP-related interventions are taken into account.

Clinical relevance

The shortened dental arch concept seems to be a relevant approach from a cost-effective point of view. Replacement of absent posterior teeth by free-end RDP cannot be recommended.     

Oral health,nutrient intake and dietary quality in the very old

BACKGROUND: Limited food choices and inadequate nutrient intake are linked to poor oral health. The authors describe relationships between dietary variety, nutrient intake and oral health measures in community-dwelling, rural Iowans aged 79 years and older. METHODS: Dental examinations were conducted by trained and calibrated examiners, and trained interviewers completed standardized interviews in subjects' homes. Subjects (n = 220) then completed three-day dietary records. Adequate nutrient intakes were defined using the Dietary Reference Intakes of the Food and Nutrition Board of the National Academy of Sciences. RESULTS: Mean daily nutrient intakes were significantly lower in subjects who had fewer natural or functional teeth and ill-fitting mandibular dentures than in subjects who had more teeth or did not have these problems. Adequacy of intakes was lower in subjects who had fewer natural or functional teeth and ill-fitting mandibular dentures. Mean daily nutrient intakes did not differ between subjects with well-fitting dentures (either complete or partial) and subjects with natural teeth. Neither mean daily intake nor adequacy of intake was associated with subjects' perceptions of oral health problems, chewing difficulties or temperature sensitivity. CONCLUSIONS: The presence of natural teeth and well-fitting dentures were associated with higher and more varied nutrient intakes and greater dietary quality in the oldest old Iowans sampled. Clinical Implications. Maintenance of natural dentition or provision and maintenance of adequate mandibular prostheses are important for nutrient intakes to support systemic health.     

Category of functional tooth units in relation to the number of teeth and masticatory ability in Japanese adults

The purposes of this study were (1) to examine differences in dental status among various age groups, particularly, focusing on whether subjects retained 20 or more natural teeth, and (2) to investigate the relationship among dental status, the number and categories of functional tooth units (FTUs), and masticatory ability. A dental examination and self-administered questionnaire were conducted in a total of 2,164 residents aged 40 to 75 years who dwelt in Japan. The percentage of subjects with 20 and more natural teeth and their number of posterior teeth decreased with age. There was not much difference in the mean number of FTUs in subjects with and without 20 or more natural teeth, but those with 20 natural teeth had fewer numbers of FTUs than those with more than 20 natural teeth. The categories of the FTUs were extremely different. Subjects with 20 or more natural teeth had FTUs consisting mostly of natural to natural teeth. Subjects with 19 or fewer natural teeth had many FTUs consisting of removable prosthetic teeth. The subjective chewing ability test was significantly correlated with the number of natural teeth. Subjects could chew the higher number of test foods as the number of natural teeth increased. Not only the number of natural teeth but the categories of FTUs appear to be key factors of chewing ability. It is important to keep as many natural teeth as possible so that the person’s categories of FTUs are mainly composed of natural to natural teeth to maintain better oral function.     

Muscle function during chewing and swallowing in patients with osseointegrated oral implant bridges. An electromyographic study.

The activity of the anterior and posterior portions of the temporal muscle, the masseter and the upper lip has been studied with electromyography in 13 women with osseointegrated oral implant bridges and compared with that in 10 subjects with natural teeth. The functions examined were chewing and swallowing of apple, bread and peanuts. There was no difference between implant and control subjects in the number of chewing cycles nor in duration of the act of chewing or in the amplitude of the muscle activity during chewing and swallowing. However, the duration of the activity during chewing was longer in the implant than in the control subjects. The number of years of wearing a maxillary implant bridge was found to be of importance for the number of chewing cycles during an act of chewing and for the muscle activity during chewing. Other factors influencing the muscle activity were age, number of occluding tooth units and the extension of the lower implant bridge. It was concluded that patients with osseointegrated oral implant bridges have a masticatory muscle function equal to or approaching that in patients with natural teeth or with bridges supported on natural teeth with the same extension of the dentition.     

Wearing of removable partial dentures in relation to dental caries

Using a representative sample of 5028 dentulous Finnish adults the occurrence of dental caries was studied among removable partial denture (RPD) wearers and non-wearers. Of the subjects wearing no RPD(s) 61.4% had one or more carious teeth, among those wearing a single RPD the figure was 60.5% and among those wearing RPDs in both jaws 62.7%, respectively. When sociodemographic background, other oral status measures than caries and oral health care habits were simultaneously controlled, subjects wearing RPDs in both jaws had slightly increased (P less than 0.05) probability of having one or more carious teeth compared to those with no RPD(s). Subjects with a single RPD did not have a statistically significantly increased probability of having carious teeth. Among those 3075 subjects who had one or more carious teeth the wearing of one or two RPDs did not significantly increase the number of carious teeth. Because the subjects wearing RPDs in both jaws were seen to have a slightly increased risk of having caries, this confirms the view that dentists should emphasize good oral hygiene habits and regular dental attendance among RPD wearers.     

Oral functional limitation among dentate adults

OBJECTIVES: The purpose of this study was to measure the prevalence of oral functional limitation in adults and to identify clinical and sociodemographic factors associated with that limitation. METHODS: The Florida Dental Care Study is a longitudinal study of risk factors for changes in oral health. Subjects (n = 873) with at least one tooth who were 45 years old or older participated in a baseline in-person interview and dental examination. Subjects were queried about oral functional limitations. RESULTS: Twenty-three percent of subjects reported difficulty chewing one or more foods using a five-item chewing index, and 10 percent reported difficulty speaking or pronouncing words because of problems with the mouth. The covariates in a multiple logistic regression identified as being significantly associated with chewing difficulty were fewer pairs of occluding anterior teeth, fewer pairs of occluding posterior teeth, more posterior teeth that are root tips, more anterior teeth that are mobile, reporting tooth pain, reporting bad breath, having but not wearing prosthetic appliances, reporting dry mouth, and being female. Having fewer anterior teeth, reporting a sore and/or broken denture, reporting unattractive teeth, and being black were significantly associated with speaking difficulty/difficulty pronouncing words because of problems with the teeth, mouth, or dentures. CONCLUSIONS: The findings in this study suggest a significant prevalence of oral functional limitation in dentate adults. Certain clinical and sociodemographic factors were strongly and independently associated with its presence.     

Relationship between clinical dental status and eating difficulty in an old Chinese population

This study investigated the relationship between clinical dental status and eating difficulty in a sample of older Chinese people in Guangxi, China. Sample was selected from people aged 55 years and older who had routine annual health check-ups at a large hospital health centre. The sample consisted of 1,196 dentate people who had clinical oral examinations and face-to-face interviews. Different measures, namely the Index of Eating Difficulty, dissatisfaction with chewing ability and ease of eating certain foods were used to measure eating difficulty. Multiple logistic regression analysis showed that after controlling for the effects of age, sex, occupation, self-assessed social class and self-perceived general health, increased eating difficulty was significantly related with having fewer teeth, fewer posterior and anterior occluding pairs of teeth (both natural teeth only and natural plus replaced teeth), more unfilled posterior spaces, more unfilled anterior spaces, mobile teeth, decayed teeth and roots. In conclusion, clinical dental status was strongly related with eating difficulty in a sample of older Chinese dentate people.     

Discrimination of inter-occlusal dimensions before and after insertion of partial dentures in man.

Nine subjects, 22–67 years of age and with no previous partial denture experience, were provided with new maxillary full dentures and mandibular bilateral distal extension (free-end saddle) partial dentures which gained retention and support from clinically-healthy teeth. After topical anaesthesia of the denture-bearing maxillary mucosa, we sought to determine the ability to discriminate minimal differences in thickness of objects, 10–100μm thick, placed between natural abutment teeth and opposing artificial teeth before and after the partial dentures had been worn for one week. The discriminatory ability, expressed as the 50 per cent sensibility threshold, showed a mean of 21μm prior to insertion of the partial dentures, but after the latter had been worn for one week the mean was 44.5 μm. In 8 subjects the discriminatory ability had declined by an average of 151 per cent but in one subject there was an 11 per cent improvement. No correlations were demonstrated between the pre-insertion and post-insertion perceptual thresholds, or between the two series of observations and the age of the subjects.     

翼式基托与磁性固位体在可摘局部义齿中的联合应用

目的评价翼式基托与磁性固位体联合应用于上颌双侧游离缺失患者的治疗效果。方法选择上颌双侧后牙全部缺失患者12例,通过磁性固位体将翼式基托与义齿主体相连接,义齿修复后即刻、修复后1个月、3个月、6个月、12个月复查,并由患者对美观、固位以及咀嚼效果进行打分评价。采用graphpad prism 6.0软件,对所得数据进行统计分析。结果 12例患者对于最终效果评价:对美观满意度达到100%,咀嚼效能满意度平均为78%,固位力满意度平均为91%。随时间变化,咀嚼功能及固位效果均有显著提高。结论将翼式基托与磁性固位体联合应用于双侧上颌后牙游离缺失患者,既能获得良好的固位效果,又能满足患者对美观的要求。     

Impact of shortened dental arches on oral health‐related quality of life

This study described the prevalence of adults with shortened dental arches (SDA) in Brazil, specifically assessing the differences of oral health‐related quality of life [the prevalence and severity of oral impacts on daily performance (OIDP)] by dentition status. We analysed data from the 2010 National Survey of Oral Health in Brazil, including home interviews and oral examinations. The assessment of SDA used two alternative definitions: having 3–5 natural occlusal units (OUs) in posterior teeth or having 4 OUs in posterior teeth. Both definitions included having intact anterior region and no dental prosthesis. The analysis was weighted, and a complex sampling design was used. Negative binomial regression models assessed associations as adjusted for socio‐demographic conditions and dental outcomes. A total of 9779 adults (35–44 years old) participated in the study. A non‐negligible proportion had SDA: 9·9% and 3·8% for the first and second definition, respectively. Individuals with SDA (first definition) ranked higher in OIDP prevalence [count ratio (CR) 1·22; 1·09–1·36, 95% confidence interval (CI)] and severity (CR = 1·43; 1·19–1·72, 95% CI) than those with more natural teeth. This difference was not statistically significant when adjusted for socio‐demographic and dental covariates: OIDP prevalence (CR = 1·04; 0·92–1·17, 95% CI) and severity (CR = 1·09; 0·91–1·30, 95% CI). Analogous results were obtained when the second definition of SDA was adopted. These findings suggest that a considerable contingent of adults may function well without dental prostheses, despite having several missing teeth. This conclusion challenges the traditional approach of replacing any missing tooth and instructs the allocation of more dental resources to preventive, diagnostic and restorative services.     

Treatment with removable partial dentures: a longitudinal study. Part II

The aim of this study was to evaluate the effectiveness of an oral rehabilitation by removable partial denture (RPD). Between 1983 and 1994, 629 patients were provided with an RPD at the Dental School of the Université catholique de Louvain. All the RPDs were constructed with a cobalt-chromium framework. All the treatments were provided by dental students under the supervision of clinical instructors. At recall time (1998-2000), 269 patients could not be reached neither by telephone nor by mail and 27 had died. Consequently, 333 patients were called for clinical examination and 254 of these (76.3%) actually attended. For a total of 292 RPDs checked 1893 persistent teeth were listed, with 804 serving as abutments; more than half (57.6%) of these were crowned, for which 51 debondings were recorded. For the period of observation we listed 79 abutments lost (37 at the upper jaw and 42 at the lower jaw), i.e. 9.8% of the total number of abutments. No relation could be established between the type of the abutments (natural or crowned teeth) and the losses observed (Test of Mantel-Haenszel: P=0.9496). In the upper jaw, the percentage of abutments lost was significantly higher in the presence of free-end edentulous areas as compared with bounded edentulous areas (Test of Mantel-Haenszel: P=0.0002); this difference does not appear for the lower jaws (P=0.9558). If we deduct the 25 abutments related with the 11 non-worn RPDs and the 79 abutments lost, no change becomes apparent for 92.2% of the maxillary abutments and for 85.8% of the mandibular abutments. For the 1089 other teeth, we observed the loss of 40 teeth and the appearance of caries or new fillings for 95 teeth. The fractures of cast clasps represent 3.4%.