bluuebunny/crossref_metadata_2025 huggingface dataset:
Dentists'attitudes to the shortened dental arch concept
Authors: WITTER D.J. , ALLEN P.F. , WILSON N.H.F. , KÄYSER A.F.
Published: August 2010

summary
The aim of restorative dentistry in high‐risk groups tends to shift over time from the preservation of complete dental arches towards the preservation of functional dental arches, using a functionally oriented approach. An example of this approach, aimed at limited treatment goals, is the shortened dental arch (SDA) concept. The objective of this study was to investigate dentists' attitudes to the SDA concept in general practice. A questionnaire seeking information pertaining to the attitudes and application of the SDA concept in clinical practice was sent to all dentally qualified members of staff in the field of restorative dentistry in the Nijmegen School of Dentistry (n= 64). From a 64% response, it was found that all but one of the respondents view the SDA concept as having a useful place in clinical practice. Although the respondents indicated only regular or occasional use of SDA in <10% of patients, the outcome of SDA management was generally satisfactory or at least sufficient, notably in the care of special category patients. The findings support the view that the SDA concept has a role in contemporary clinical practice.
Bonding of titanium with acidic primers and a tri‐n‐butylborane‐initiated luting agent
Authors: TAIRA Y. , MATSUMURA H. , ATSUTA M.
Published: August 2010

summary
Adhesive bonding of titanium was investigated with the use of five primers and two luting agents. All of the primers contained acidic methacrylate monomers for promotion of metal bonding. Titanium metal specimens were bonded with seven combinations of five primers and two luting agents. Durability of the bond was evaluated by means of thermocycling. Although all five primers enhanced the bond strength to titanium, three of the primers (Super‐Bond Liquid, Metal Primer and Tokuso Rebase MR. Bond) demonstrated more durable bonds than the other two primers (Acryl Bond and All‐Bond 2 Primer B). The tri‐n‐butylborane (TBB)‐initiated luting agent exhibited better bonding ability as compared to conventional composite resin. The strongest and the most consistent bond was achieved by the combination of 4‐methacryloyloxyethyl trimellitate anhydride (4‐META) primer and TBB resin.
Relationship between incisal tooth wear and the increasing number of permanent teeth in children and adolescents
Authors: SILNESS J. , BERGE M. , JOHANNESSEN G.
Published: August 2010

summary
The material presented in this report was derived from a longitudinal study of the development and progress of incisal tooth wear in children and adolescents. The study group was established in 1991/1992 and consisted of 77 participants between 8 and 15 years old. All participants were re‐examined in 1994. The interval between the first and second examination was approximately 32 months. Each participant was scored for tooth wear of the anterior teeth of both jaws according to the Incisal wear Index (IwI) and the number of permanent teeth and the tooth types present were recorded at each examination. The results showed that the pattern of incisal wear had been maintained during the observation period. Severity of incisal wear increased as the number of teeth increased. The strength of the relationship between incisal wear and the number of teeth decreased during the observation period. At the same time, the number of teeth and the size of the wear increments were negatively correlated indicating that the rate of wear progression decreased as the number of teeth increased.
Brazing joints of gold alloy used in porcelain‐fused‐to‐metal restorations and their resistance to deflection fatigue
Authors: VALLITTU P. K.
Published: August 2010

summary
The aim of this study was to compare the resistance to deflection fatigue of a gold alloy used in porcelain‐fused‐to‐metal restorations with and without a brazing joint. Pre‐ceramic brazing filler metal was used to join the parent specimens of gold alloy together. The deflection fatigue test was carried out mainly with 0.4 m deflection of the test specimens (n= 5) but to obtain an S–N curve for the specimens, other magnitudes of deflection, i.e. the stress, were also used. When the fracture surface of the test specimens was examined by scanning electron microscopy (SEM), the results showed that the brazing joint in the gold alloy test specimen decreases the fatigue resistance considerably compared to that of specimens without a brazing joint (P= 0.002). SEM examination showed that the failure type of the brazing joint was cohesive and that the brazing filler metal had a more porous structure than the parent gold alloy. These results suggest that, due to the occlusal biting forces in situ, the brazing joints in fixed partial dentures can be fractured by metal fatigue.
Unerupted canine without median diastema
Authors: YAMAOKA M. , FURUSAWA K. , TANAKA M. , TANAKA H.
Published: August 2010

summary
The eruption of the canine is known to be a factor for diastema closure. In this study the relative changes in the orientation of the unerupted canine were assessed using the orthopantomographs of 9854 patients who sought consultation between April 1984 and March 1993. A total of 38 canines in 32 patients, all aged 11 years or older, were identified as unerupted canines. The features of the patients with unerupted canine showed no significant relation to diastema closure status, but some patients had unerupted horizontal or inverted canine without diastema even in the absence of a history of orthodontic treatment, suggesting the presence of a mechanical force due to some phenomenon other than canine eruption as a factor in diastema closure.
Denture stomatitis in an elderly edentulous Asian population
Authors: JEGANATHAN S. , PAYNE J.A. , THEAN H.P.Y.
Published: August 2010

summary
Denture stomatitis is a common oral disease in denture wearers. Multiple aetiological and predisposing factors are believed to be responsible for its initiation and progression. The aim of this study was to assess the relationship between denture age, denture hygiene habits, denture wearing and denture cleanliness in an elderly edentulous Asian population. Seventy‐five edentulous patients, all wearing maxillary complete dentures were divided into two groups. The test group comprised 36 patients (14 male and 22 female) with Type II denture stomatitis. The control group comprised 39 subjects (14 male and 25 female) with clinically healthy palatal mucosa. A standardized interview and clinical appraisal were carried out. The dye disclosing method was used to assess denture cleanliness and the resultant staining pattern scored. Statistical appraisal between the two groups revealed significant differences in denture hygiene habits (P<0.05), denture wearing behaviour (P<0.01) and denture cleanliness (P<0.01). No significant difference was observed in the age of dentures between the test group and controls (P>0.05). In the studied Asian edentulous population, a relationship between denture hygiene habits, denture wearing behaviour and denture cleanliness to the presence of denture stomatitis was observed.
Reinforced glass–ionomer cements: the influence of conditioners on marginal leakage
Authors: YAP A.U.J. , MOK B.Y.Y.
Published: August 2010

summary
The purpose of this in vitro study was to evaluate the influence of conditioners on the enamel and dentine margin sealing ability of three different reinforced glass–ionomer cements. Two Class V preparations were made on the buccal and lingual surfaces of 36 freshly extracted molar teeth. Preparations were solely in enamel or dentine/cementum. The teeth were randomly divided into three groups of 12 and restored with either Ketac Silver® (KS), Hi‐Dense® (HD) or Miracle‐Mix® (MM) with and without (–C) their respective conditioners. All materials were capsulated and were manipulated according to the manufacturers’instructions. The restorations were finished as recommended by the manufacturers and then stored in saline at 37°C for 1 week, polished, thermally stressed, subjected to dye penetration, sectioned and scored. Rankings in the order of decreasing leakage were as follows: enamel margin KS>KS–C>HD–C>HD>MM>MM–C; dentine margin KS>HD–C>KS–C>HD>MM–C>MM. At the enamel margins, only HD showed a significant increase in leakage when conditioner was not used. At the dentine margin, however, KS had significantly more leakage than KS–C and HD–C had significantly more leakage than HD. There was no significant difference in leakage for MM both with and without conditioner. The influence of conditioners on marginal leakage appears to be both product and tissue specific.
A new method for assessing masticatory performance: a feasibility and reproducibility study
Authors: HUGGARE J. , SKINDHÖJ B.
Published: August 2010

summary
The aim of this study was to develop a method for assessing masticatory performance based on incorporation of a colour binder in a test material with the presumption that the absorption of the colour is proportional to the total surface area of the masticated material. This was tested in vitro with erythrosin as the colour substance and Praestol 655BC as the colour binder incorporated into Satou's synthetic test material (equal amount of carnauba wax and bariumsulphate). The authors found that the difference in spectrophotometrical absorbance between a standard erythrosin solution and the supernatant of the same solution incubated half an hour with artificially pulverized test material was almost linearly correlated (r=0.997) with the particle surface. This test material was then fabricated as small tablets and four adults chewed repeatedly five grams of these tablets to assess selectivity and reproducibility of the method. A good selectivity was found .in that within the total range of the difference in absorbance (0.47–1.19) an inter‐individual difference of more than 0.17 is significant on a 95% level with double experiments. There were no differences in the intra‐individual variation for double determinations between immediate repeat and 1 week interval performances but the reproducibility was disturbed when two subjects used their partial dentures.
The effects of bolus size and chewing rate on masticatory performance with artificial test foods
Authors: BUSCHANG P.H. , THROCKMORTON G.S. , TRAVERS K.H. , JOHNSON G.
Published: August 2010

summary
To better understand ‘within subject’ variability in masticatory performance of artificial food, this study evaluates the effects of bolus size and chewing rate. Twenty young adult male subjects each participated in two experiments evaluating their ability to process an artificial food (CutterSil®). Based on the frequency distributions for the weights of the chewed particles, median particle size and broadness of the particle distribution were estimated. Controlling for the number of chews, the effect of (1) bolus size was evaluated by having each subject chew one whole tablet, four quarters, three quarters or two quarters; (2). chewing rate was evaluated by having the subjects chew first habitually, then at slow (40 cycles/min) and fast (100 cycles/min) rates. The results showed that median particle sizes decreased and the distribution of particles widened with decreasing bolus size. The slow chewing rate produced the smallest particles with the widest distributions, followed by the habitual and fast rates, respectively. The study has shown that bolus size and chewing rate are important source of variation which must be considered in studies of masticatory performance.
Studies on dental high‐speed cutting of commercial pure titanium (Ti) and free‐machining titanium (DT‐2F)
Authors: TAIRA M. , OKAZAKI M. , TAKAHASHI J. , YAMAKI M.
Published: August 2010

summary
Some dental prostheses are formed by machining. The purpose of this study was to evaluate the dental high‐speed cutting behaviour of free‐machining titanium (Ti), the ease in cutting of which is metallurgically improved. Weight‐load cutting tests were performed on commercial pure Ti and free‐machining Ti, using a diamond point and a carbide burr. It became evident that the cutting effectiveness of two rotary cutting instruments on free‐machining Ti was superior to that on commercial pure Ti due to the formation of accelerated cut debris. Cutting of free‐machining Ti resulted in less damage of the carbide burr, compared with the cutting of commercial pure Ti. These results suggest that free‐machining Ti is a suitable workpiece for dental Ti‐based machined prostheses.
The effect of potential investment expansion and hot strength on the fit of full crown castings made with phosphate‐bonded investment
Authors: EARNSHAW R. , MOREY E.F. , EDELMAN D.C.
Published: August 2010

summary
In an earlier investigation, it was shown that when full crowns are cast in gypsum‐bonded investments, their relative inaccuracy is affected by both the investment's potential expansion and its hot strength. This study repeated the earlier one, but used a high‐melting gold alloy and two phosphate‐bonded investments. The investments were used under conditions which gave a range of potential expansions and hot strengths. Casting inaccuracies were determined both diametrally and axially. All castings showed distortion, which varied under the different conditions. All were oversized axially, by amounts varying from +0·8% to +2·3%. Diametral inaccuraciesranged from −0·2%to+0·7%. Investment expansion had a strong effect on axial inaccuracy, but a negligible effect on diametral inaccuracy. Conversely, hot strength had a strong effect on diametral inaccuracy, but only a very weak effect on axial inaccuracy. With phosphate‐bonded investments, both potential expansion and hot strength are important parameters of relative casting inaccuracy. In combination, these properties showed very strong correlations with both diametral and axial inaccuracies. The observed distortions were the result of anisotropic mould expansion and anisotropic alloy shrinkage. The best fit, and least distortion, occurred with an investment setting under dry conditions.
Clinical performance of porcelain laminate veneers. A retrospective evaluation over a period of 6.5 years
Authors: SHAINI F.J. , SHORTALL A.C.C. , MARQUIS P.M.
Published: August 2010

summary
Three‐hundred and seventy‐two porcelain laminate veneers were fitted to defective and discoloured teeth in 102 patients. Ninety per cent of the restorations were fitted to unprepared teeth. Restorations were reviewed up to 78 months after cementation. Survival probabilities were calculated using the Kaplan‐Meier method. Results showed higher rates of failure and problem development in veneers fitted over existing restorations and in those fitted by inexperienced operators. A considerable number of veneers suffered minor problems that were successfully repaired.
Film thickness of various dentine bonding agents
Authors: PETER A. , PAUL S.J. , LÜTHY H. , SCHÄRER P.
Published: August 2010

summary
Curing dentine bonding agents create a film thickness on the surface of teeth which are prepared for all‐ceramic crowns. The aim of this study was to investigate if the film thickness of dentine bonding agents (DBAs) is acceptable with the fit of definitive restorations of 50–100 μ. AllBond 2®, Syntac®, ART Bond®, P‐Bond® (an experimental DBA), and the Primer of AllBond 2 were applied onto teeth which were prepared with standardized all‐ceramic crown preparations. The DBAs were applied onto the prepared tooth surfaces according to manufacturers’instructions and under a standardized simulation of intrapulpal pressure. After curing the DBAs, the teeth were cut mesiodistally and orolingually and the film thickness was measured under a light microscope. Only the film thicknesses of AllBond 2 and P‐Bond were low enough and, therefore, would enable curing to take place immediately after their application.
Effects of salivary or serum pellicles on the Candida albicans growth and biofilm formation on soft lining materials in vitro
Authors: NIKAWA H. , HAMADA T. , YAMAMOTO T. , KUMAGAI H.
Published: August 2010

summary
The effects of salivary or serum pellicle on Candida albicans growth, biofilm formation and cavitation on the soft lining materials were examined. Both saliva and serum pellicles reduced the antifungal effects of soft liners. The fungal biofilm formation on these materials varied depending upon both the materials tested and protein‐coats, and the pellicles which significantly enhanced the biofilm formation. Similarly, the pellicles enhanced the firm colonization and hyphal invasion of the yeasts on the specimens, although the cavitation appeared to be regulated by the plasticizer used. These results suggest that the interactions between proteinaceous pellicle, tissue conditioners and fungi are complex. They also suggest that denture pellicles facilitate fungal plaque formation onto soft lining materials through several mechanisms such as reduction of the antifungal effects of soft liners, facilitation of biofilm formation, firm colonization and hyphal invasion. In addition, the composition of the materials is also involved in the susceptibility to the fungi.
The closure of the gingival crevice following gingival retraction for impression making
Authors: LAUFER B.‐Z. , BAHARAV H. , LANGER Y. , CARDASH H. S.
Published: August 2010

summary
Scant attention has been paid to the effectiveness of chemomechanical displacement of the gingiva prior to impression making for fixed partial dentures. The closure of the gingival crevice following removal of medicated retraction cord was observed using a miniature video camera. Sulcular widths were measured at time intervals at the midbuccal and transitional line angle areas. The closure rate of the transitional line angle area was significantly faster than that of the mid‐buccal area during the first 90 s. An average sulcular width of 0–2 mm was reached at the transitional line angle after less than 30 s.
Marginal adaptation of a sintered ceramic inlay system before and after cementation
Authors: GEMALMAZ D. , ÖZCAN M. , YORUÇ A.B. , ALKUMRU H.N.
Published: August 2010

summary
The long term clinical performance of porcelain inlays depends on a number of factors and the marginal adaptation is one of significant interest. The purpose of this in vitro study was to evaluate the marginal integrity of a sintered inlay technique (Ducera®), before and after cementation. MOD cavities without bevels were prepared on 10 human mandibular molar teeth and porcelain inlays were fabricated according to the manufacturer's instructions. Inlays were evaluated microscopically for their adaptation to the occlusal and approximal margins of the tooth by means of a replica technique. Inlays were cemented with a dual‐cured bybrid composite luting material (Enforce®). After polishing, each tooth was sectioned in buccal/lingual and mesial/distal directions following the same procedure in the sectioning of replicas. The marginal gap and the thickness of exposed cement were measured at each section. The mean marginal gap of 71.83 ± 8.93 μm recorded for the occlusal margin before cementation was significantly smaller than that of 1056 ± 39.33 μm calculated at the approximal margin. Following the cementation, the adaptation of the inlays at the occlusal margin was also found to be superior to that of the approximal margin. Comparison of mean gap values before and after cementation revealed that the marginal gap increased by 6.94 μm and 23.25 μm at the occlusal and approximal margins, respectively. Although polishing was performed after cementation, excess luting material was still observed, that caused an increase in the width of the exposed luting cement.
Titanium for removable partial dentures (III): 2‐year clinical follow‐up in an undergraduate programme
Authors: Au A. R. , Lechner S. K. , Thomas C. J. , Mori T. , Chung P.
Published: August 2010

This study examined the success of titanium (Ti) removable partial dentures (RPDs) compared with that of cobalt–chromium (Co–Cr) RPDs using a randomized controlled clinical trial. Thirty‐eight RPD patients were provided with either Co–Cr (20 patients) or Ti (18 patients) RPDs. The total numbers of dentures was 31 (13 maxillary, 18 mandibular) for Co–Cr and 23 (11 maxillary, 12 mandibular) for Ti. Patients were reviewed for 24 months following denture issue. After the initial 12 months, 20 clinical problems were recorded and became the criteria for subsequent assessment. Incidence of failure was analysed using both Fisher's exact test and the chi square test at a significance level of P<0·05. Fracture of retainers in both metals occurred only in the first 12 months. Some failure types presented at significantly higher levels in the first 12 months but there were no significant differences between the two in all the criteria examined between the 12‐ and the 24‐month reviews. Although differences existed in failure types between Co–Cr and Ti RPDs during the early review stages, the overall success rate of Ti RPDs was comparable with that of Co–Cr RPDs after 24 months. The higher incidence of failures in Ti RPDs prior to the 12‐month review suggests the importance of taking its lower rigidity into account when designing RPDs.
Saliva tannin interactions
Authors: Prinz J. F. , Lucas P. W.
Published: August 2010

Many plant foods contain tannins, compounds that bind proteins, such as mammalian enzymes. Although described as tasteless, tannins can be detected orally by their astringency. However, the actual mechanism of oral detection and the effect of tannins on mastication and swallowing have been little investigated. Here, we show from in vitro tests that tannic acid, a common standard in tests used to detect tannins, significantly reduces the lubricating qualities of human saliva both by decreasing its viscosity and increasing friction, both factors lending support to the notion that astringency is a tactile phenomenon. From the literature, it is clear that this effect depends on the presence of salivary proline‐rich proteins (PRP). In a mammalian context, ingestion of tannin‐rich foods in a species with salivary PRP will be signalled by interference with bolus formation during mastication while the increase in friction may also be detectable and lead to increased tooth wear if the signal is ignored. In a human context, cross‐cultural preferences for tannin‐rich beverages such as tea, coffee and red wine at the end of meals may be explained by reduction in adhesion of food particles to the oral mucosa allowing their rapid oral clearance.
A method for quantifying overall satisfaction of complete denture patients
Authors: Sato Y. , Hamada S. , Akagawa Y. , Tsuga K.
Published: August 2010

Reproducible and quantitative evaluation of patient satisfaction with their complete dentures is of great importance for preoperative diagnosis, treatment planning and assessment of complete denture treatment outcome. This study attempted (1) to clarify the degree of contribution of various factors to overall satisfaction, and (2) to develop a method for quantitative assessment of overall satisfaction with complete dentures. Twelve satisfaction factors and a three‐grade scale were used to assess 302 complete denture patients. The contribution of each grade of the 12 factors to the overall satisfaction level was determined by multiple regression analysis. Seven factors were highly correlated to the overall satisfaction. Based on the level of contribution by these seven significant factors, a scoring method for satisfaction was established. Category scores for these factors were calculated and the sum of the category scores was converted to an integer between 0 and 100. The resulting quantification score was closely correlated with overall satisfaction. A protocol for scoring overall satisfaction was developed based on the scientifically analysed contribution of each satisfaction factor.
The effect of venting on pulpward pressure transmission and seating on crown cementation: a laboratory study
Authors: Yuen T. W. H. , Wilson P. R.
Published: August 2010

Measurable hydraulic forces towards the pulp chamber can occur whilst cementing a crown. This study investigated the effect of crown venting and the use of two different seating forces (100 and 2·5 N) on pulpward pressure transmission. Forty single‐rooted premolar teeth were collected from patients requiring extractions for orthodontic reasons. A standardized crown preparation was made and impressions taken to construct individual base‐metal alloy crowns. The teeth were divided into four groups based on the type of crown (vented or non‐vented) and force used (100 or 2·5 N). The teeth mounted on a specially constructed stand and connected to a 0–104 kPa pressure transducer. The pulp chamber was perfused with saline driven by nitrogen gas at 83 kPa for up to 2 h until a steady state perfusion rate was achieved. Crowns were cemented to the teeth on a uniaxial seating device using zinc phosphate cement. Simultaneous recordings of both pressure pulse and seating discrepancies were recorded. The 40‐fold increase in seating force from 2·5 to 100 N resulted in a significant increase (P<0·001) in pulpward pressure in both vented and non‐vented crowns. Seating was also significantly improved for the vented crowns regardless of which force was used. Venting had no significant effect on pulpward pressure transmission. It was concluded that a significant relationship existed between seating force and pulpward pressure transmission. Venting improved crown seating but did not have a demonstrable effect on pulpward pressure transmission.
Functional subdivision of the human masseter and temporalis muscles as shown by the condylar movement response to electrical muscle stimulation
Authors: Lobbezoo F. , Zwijnenburg A. J. , Naeije M.
Published: August 2010

In previous studies from our laboratory, a functional subdivision of the human temporalis and masseter muscles was demonstrated by means of opto‐electronic recordings of the lower incisal point movement responses to electrical muscle stimulation. In the present study, it was examined whether this subdivision was also reflected in different movement responses of the mandibular condyle. To that end, the condylar movement responses to unilateral stimulation of four masseter muscle parts and three temporalis muscle parts were studied in four different jaw positions. The kinematic centre was used for condylar reference point. For both the amplitude and the direction of the movement responses, the effects of stimulation location and jaw position were studied using multivariate anova and contrast analyses. It was found that for both outcome variables, the functional subdivision of the masseter and temporalis muscles was also reflected in some, but not all, of the movement responses of the mandibular condyles. The deep masseter muscle part and the (anterior) temporalis muscle part responded similarly to electrical stimulation.
An appraisal of the literature on centric relation. Part II
Authors: Keshvad A. , Winstanley R. B.
Published: August 2010

The literature directly and indirectly related to centric relation (CR) has been reviewed chronologically. More than 300 papers and quoted sections of books have been divided into three sections. The first two parts of the paper are related to CR. Studies in this group mainly compared either the position of the mandibular condyle or the mandible itself in different CR recordings. Various tools were discussed for this purpose. The third part deals with CR–centric occlusion (CO) discrepancy. CR remains one of the controversial issues in prosthodontics and orthodontics. Debates relating to mounting casts on the articulator by reproducible records for orthodontic treatment planning and end results, and whether or not orthodontic treatment based on CO causes temporomandibular joint (TMJ) dysfunction, remain unsolved. The references are listed at the end of Part III.
Frontal‐plane lateral border movements and chewing cycle characteristics
Authors: Rilo B. , Fernandez J. , Da Silva L. , Martinez Insua A. , Santana U.
Published: August 2010

We studied the dental contact section of the chewing cycle, the most important section in terms of function (as it governs the effectiveness of food trituration). Specifically, we determined closing phase dental contact distance and lateral path inclination in a sample of healthy subjects, and investigated possible relationships between these variables and Ahlgren chewing cycle type. The chewing cycle was characterized in 63 healthy subjects by frontal plane kinesiography. In all cases kinesiographs were obtained for both right‐ and left‐side chewing, with chewing gum as bolus. In all cases we determined closing phase dental contact distance, lateral path inclination and Ahlgren chewing cycle type. Most subjects (84%) showed ‘normal’ chewing cycles (Ahlgren types I–IV); inverted, contralateral and irregular cycles (types V–VII) were infrequent. Mean dental contact distance was 0·9 mm for right‐side chewing and 1·2 mm for left‐side chewing. Mean lateral path inclination was 35° for right‐side chewing and 37° for left‐side chewing. Normal chewing cycles are generally bilateral, whereas abnormal chewing cycles are never bilateral. Border movement distance does not differ in any consistent way between ‘chopping’ and ‘grinding’ chewing cycle types. Closing phase dental contact distance showed a significant positive correlation with lateral path inclination.
Dimensional stability and weight changes of tissue conditioners
Authors: Murata H. , Kawamura M. , Hamada T. , Saleh S. , Kresnoadi U. , Toki K.
Published: August 2010

The dimensional stability of tissue conditioners characterizes the ability of the materials to yield accurate functional impressions of oral mucosa. This study evaluated the linear dimensional changes with time of six tissue conditioners (COE Comfort, FITT, GC Soft‐Liner, Hydro‐Cast, SR‐Ivoseal and Visco‐Gel) using a travelling microscope, and relationship between these changes and weight changes. The absorption and solubility of these materials were also determined. The percentage changes in dimension and weight in water storage were measured at 2 (baseline), 8 and 24 h, and 2, 4, 7, 14 and 21 days after specimen preparation. All materials except SR‐Ivoseal exhibited shrinkage and weight loss during water storage, whilst SR‐Ivoseal exhibited expansion and an increase in weight. The percentage solubility for all materials except SR‐Ivoseal was higher than the percentage absorption. A positive linear relationship was found between the percentage changes in linear dimension and those in weight (r=0·797 − 0·986, P < 0·05). Water absorption and solubility of the materials were found to be associated with dimensional changes. The results suggest that the period recommended for forming functional impressions would be 24 h after insertion in the mouth. In addition, it is important to select tissue conditioners suitable for functional impressions because of the wide ranges of dimensional stability among the materials.
Localization of keratan sulphate and chondroitin‐6‐sulphate on the anteriorly displaced human temporomandibular joint disc – histological and immunohistochemical analysis
Authors: Fujita S. , Iizuka T. , Dauber W.
Published: August 2010

The aetiology of temporomandibular joint (TMJ) disc displacement has been investigated using human post‐mortem material. Twenty TMJ specimens were used for a histological procedure with haematoxylin and eosin staining and orceine staining. Immunohistological analysis with chondroitin‐6‐sulphate and keratan sulphate was also carried out on the same specimens. Immunohistochemically, the specific localization of chondroitin‐6‐sulphate and keratan sulphate in the antero‐medial parts of the anteriorly displaced deformed TMJ disc, which may be load‐bearing areas, was observed. Orcein staining revealed that specific elastic fibres pulling the anterior band and stretching the disc continuously, may be an important factor in disc displacement. On the basis of these results, we were able to propose a significant new hypothesis for the aetiology of disc displacement.
Relationship between the stress distribution and the shape of the alveolar residual ridge – three‐dimensional behaviour of a lower complete denture
Authors: Kawasaki T. , Takayama Y. , Yamada T. , Notani K.
Published: August 2010

Purpose: For a complete denture to function effectively, the denture must be stabilized during mastication. The alveolar ridge has various forms, and we must choose the artificial tooth arrangement that is most suitable to the form of the alveolar ridge. The purpose of this study was twofold: (i) to examine the relationship between the alveolar ridge form and the stress distribution on the mucosa, and (ii) to model the contact condition between the denture base surface and mucosa. Materials and methods: In this study, the three‐dimensional finite element method was used for the analysis. Four types of alveolar ridge were prepared. As a loading condition, three load places were prepared: the mesial position, the central position and the distal position. We utilized the ‘contact option (MARC)’ to simulate the true behaviour of the denture. Results: We were able to model the contact condition by using the ‘contact option’. Maximum stresses were distributed on the alveolar ridge in which the absorption is severe. And, the distal load produced large compressive stresses on the inclined plane of posterior alveolar ridge in which alveolar form.
The effects of isometric exercise on maximum voluntary bite forces and jaw muscle strength and endurance
Authors: Thompson D. J. , Throckmorton G. S. , Buschang P. H.
Published: August 2010

The effects of training and exercise on the strength and endurance of limb muscles has been investigated extensively, but the response of the jaw muscles to exercise remains poorly known. The purpose of this study was to determine whether short‐term isometric training increases strength and endurance of the superficial masseter and anterior temporalis muscles. Maximum and submaximum voluntary bite forces and corresponding electromyographic (EMG) activity were measured in 28 young adults, randomly divided into exercise and non‐exercise (control) groups. Subjects in the exercise group performed isometric clenches against a soft maxillary splint for five 1‐min sessions per day over a 6‐week period. After exercise, subjects increased their maximum bite forces by 37%, but control subjects’ bite forces also increased by 25%. After exercise, EMG levels per unit of bite force generally decreased, but similar decreases were also seen in the non‐exercised controls. Masseter muscle activity levels during standardized 10‐kg bites decreased after 6 weeks of exercise. Fatigue resistance increased significantly with exercise but did not differ significantly from control values after 6 weeks of exercise. The results of this study indicate that increases in maximum bite force can be easily produced with training, but that actual strengthening of the jaw muscles is more difficult to achieve.
Comparison of the erosive potential of gastric juice and a carbonated drink in vitro
Authors: Bartlett D. W. , Coward P. Y.
Published: August 2010

The aim of this study was to compare the erosive effect of gastric juice and a carbonated drink on enamel and dentine by measuring release of calcium from 30 hemisectioned teeth in vitro. In addition, the titrable acidity (mL of 0·05 M sodium hydroxide required to neutralize) and pH of the fluids was estimated. The mean pH of the seven gastric acid samples was 2·92 (range 1·2–6·78) and mean titratable acidity 0·68 mL (range 0·03–1·64). Both the pH and the titratable acidity of the gastric juice varied between patients all of whom suffered from symptoms of reflux disease. The carbonated drink had a pH of 2·45 and a titratable acidity of 0·29 mL. The median amount of calcium released by the gastric acids from enamel was 69·6 μg L–1 (interquartile range 5·4–144) and 62·4 μg L–1 (2·2–125·3) from dentine. The carbonated drink released 18·7 μg L–1 (13·4–23·4) and 18·6 μg L–1 (11·9–35·3), respectively. The differences in calcium release by gastric juice and the carbonated drink were statistically significant for both enamel (P < 0·005) and dentine (P < 0·01). It is concluded that gastric juice has a greater potential, per unit time, for erosion than a carbonated drink.
Validity of a laser fluorescence system (DIAGNOdent) for detection of occlusal caries in third molars: an in vitro study
Authors: Başeren N. M. , Gokalp S.
Published: August 2010

summary  The aim of this study was to compare the validity of the measurements of the laser fluorescence device, KaVo DIAGNOdent®, with the result of polarized light microscopy in the detection of occlusal fissure caries in extracted third molars. Ten impacted, surgically removed, and 25 extracted third molars with macroscopically intact occlusal surfaces were selected. The DIAGNOdent measurements of the occlusal test site were recorded by two observers at intervals of 2 days. The teeth were then sectioned at the specified test sites for histological examinations. Prepared specimens were evaluated under the polarized light microscopy and all images were scored with the caries classification of D1 (sound and fissure lesion in the half of the outer enamel), D2 (enamel decay) and D3 (dentin decay) level (gold standard). The kappa value for the inter‐observer repeatability was calculated and the value 0·83 for the first measurements and 0·67 for the second measurement were obtained,respectively. Inter‐observer correct classification percentages were 88·5 and 77·1 for the first and second measurements, respectively. The kappa value for intra‐observer repeatability was 0·79 for the first observer and 0·75 for the second observer. Intra‐observer correct classification percentage values were 85·7 and 82·8 for the first and second observer, respectively. Value of specificity for the detection of enamel caries at D1 level was 0·74 and sensitivity values at D2 and D3 levels were 0·66 and 1·00, respectively. The present study indicates that the DIAGNOdent® provides not only almost perfect agreement but also sufficient repeatability at D1, D2, D3 levels and better specificity at D1 level as well as lower sensitivity at D2 level and excellent sensitivity at D3 level.
Clinical evaluation of low‐level laser therapy and fluoride varnish for treating cervical dentinal hypersensitivity
Authors: Corona S. A. M. , Nascimento T. N. do , Catirse A. B. E. , Lizarelli R. F. Z. , Dinelli W. , Palma‐DIBB R. G.
Published: August 2010

summary  The aim of this study was to evaluate in vivo the use of low‐level galium–aluminium–arsenide (GaAlAs) (BDP 600) laser and sodium fluoride varnish (Duraphat®) in the treatment of cervical dentine hypersensitivity. Twelve patients, with at least two sensitive teeth were selected. A total of 60 teeth were included in the trial. Prior to desensitizing treatment, dentine hypersensitivity was assessed by a thermal stimulus and patients’ response to the examination was considered to be a control. The GaAlAs laser (15 mW, 4 J/cm2) was irradiated on contact mode and fluoride varnish was applied at cervical region. The efficiency of the treatments was assessed at three examination periods: immediately after first application, 15 and 30 days after the first application. The degree of sensitivity was determined following predefined criteria. Data were submitted to analysis and no statistically significant difference was observed between fluoride varnish and laser. Considering the treatments separately, there was no significant difference for the fluoride varnish at the three examination periods, and for laser therapy, significant difference (P < 0·05) was found solely between the values obtained before the treatment and 30 days after the first application. It may be concluded that both treatments may be effective in decreasing cervical dentinal hypersensitivity. Moreover, the low‐level GaAlAs laser showed improved results for treating teeth with higher degree of sensitivity.
Relationship between the craniofacial complex and size of the resorbed mandible in complete denture wearers
Authors: Nissan J. , Barnea E. , Zeltzer C. , Cardash H. S.
Published: August 2010

summary  A cephalometric study was conducted on 34 complete denture wearers to examine the relationship between the area of the mandible and the skeletal facial form, the area of the mandible and the gonial angle, and the area of the mandible and the length of the mandible. No significant correlation was found between the area of the mandible and the skeletal facial types or the gonial angle. A statistically significant correlation (P < 0·0028) was found between the length of the mandible and the area of the mandible. Residual resorption of the mandible appears to be independent of skeletal facial form and the gonial angle.
Asymmetric muscle function in patients with developmental mandibular asymmetry
Authors: DONG Y. , WANG X. M. , WANG M. Q. , WIDMALM S. E.
Published: August 2010

Summary  The aim was to test the hypothesis that developmental mandibular asymmetry is associated with increased asymmetry in muscle activity. Patients with mandibular condylar and/or ramus hyperplasia having unilateral cross‐bite were compared with healthy subjects with normal occlusion. Muscle activity was recorded with surface electrodes in the masseter, suprahyoid, sternocleidomastoid muscle (SCM) and upper trapezius areas during jaw opening–closing–clenching, head–neck flexion–extension, and elevation–lowering of shoulders. Root mean square (RMS) and mean power frequency (MPF) values were calculated and analysed using anova and t‐tests with P < 0·05 chosen as significance level. The SCM and masseter muscles showed co‐activation during jaw and head movements, significantly more asymmetric in the patients than in the healthy subjects. The RMS and MPF values were higher in the patients than in the controls in the SCM and suprahyoid areas on both sides during jaw opening–closing movement. The results indicate that the ability to perform symmetric jaw and neck muscle activities is disturbed in patients with developmental mandibular asymmetry. This is of clinical interest because asymmetric activity may be an etiologic factor in temporomandibular joint and cervical pain. The results support that co‐activation occurs between jaw and neck muscles during voluntary jaw opening and indicate that postural antigravity reflex activity occurs in the masseter area during head extension. Further studies, where EMG recordings are made from the DMA patients at early stages are motivated to verify activity sources and test if the asymmetric activity is associated with muscle and joint pain in the jaw and cervical areas.
Nasal speaking valve: a device for managing velopharyngeal incompetence1
Authors: SUWAKI M. , NANBA K. , ITO E. , KUMAKURA I. , MINAGI S.
Published: August 2010

Summary  Velopharyngeal incompetence is a contributing factor for speech disorders, and other frequently accompanying disorders, such as cleft palate, congenital paralysis of the soft palate and cerebrovascular disease. A palatal lift prosthesis (PLP) has been fabricated for managing velopharyngeal incompetence to improve speech. Because of discomfort, such as difficulty in swallowing or vomiting reflex, while wearing the PLP, rigorous adjustment is required. Patients may have difficulty becoming accustomed to using the prosthesis. This article reports on a newly developed device, the nasal speaking valve, for improving hypernasal speech caused by velopharyngeal incompetence.
Effects of light on cyanide‐resistant respiration and alternative oxidase function in Arabidopsis seedlings
Authors: ZHANG DA‐WEI , XU FEI , ZHANG ZHONG‐WEI , CHEN YANG‐ER , DU JUN‐BO , JIA SHU‐DAN , YUAN SHU , LIN HONG‐HUI
Published: August 2010

Mitochondrial alternative oxidase (AOX), the unique respiratory terminal oxidase in plants, catalyzes the energy wasteful cyanide (CN)‐resistant respiration and plays a role in optimizing photosynthesis. Although it has been demonstrated that leaf AOX is upregulated after illumination, the in vivo mechanism of AOX upregulation by light and its physiological significance are still unknown. In this report, red light and blue light‐induced AOX (especially AOX1a) expressions were characterized. Phytochromes, phototropins and cryptochromes, all these photoreceptors mediate the light‐response of AOX1a gene. When aox1a mutant seedlings were grown under a high‐light (HL) condition, photobleaching was more evident in the mutant than the wild‐type plants. More reactive oxygen species (ROS) accumulation and inefficient dissipation of chloroplast reducing‐equivalents in aox1a mutant may account for its worse adaptation to HL stress. When etiolated seedlings were exposed to illumination for 4 h, chlorophyll accumulation was largely delayed in aox1a plants. We first suggest that more reduction of the photosynthetic electron transport chain and more accumulation of reducing‐equivalents in the mutant during de‐etiolation might be the main reasons.
Indications That the Cγ2 Homology Region Is Not a Regular Domain
Authors: MICHAELSEN T. E.
Published: August 2010

The Cγ2 homology region of rabbit IgG does not behave like a domain. Thus, there is no trans‐interaction between the two Cγ2 regions: instead there is an unusual cis‐interaction between Cγ2 and Cγ3 regions. The observations were made on the plasmin digestion products Facb (IgG minus the Cγ3 region) and pFc’(Cγ3 region), which did not dissociate under neutral conditions but dissociated in 3M guanidine solution (that is. cis‐interaction between Cγ2 and Cγ3). The Facb fragment split into subunits with equal molecular weights under neutral conditions on partial reduction and alkylation (that is, lack of transinteraction between the two Cγ2 in the molecule).
Identification of Resting Human T and B Lymphocytes by Acid α‐Naphthyl Acetate Esterase Staining Combined with Rosette Formation with Staphylococcus aureus Strain Cowan 1
Authors: RANKI A. , TÖTTERMAN T. H. , HÄYRY P.
Published: August 2010

We describe a method enabling the identification of both lymphocyte class and morphology from a single microscopic slide. As a marker for B cells we used surface immunoglobulin. The surface‐Ig‐carrying cells were rosetted after polyvalent anti‐Ig treatment with Staphylococcus aureus strian Cowan 1 (StaCw) and the cells were cytocentrifuged onto a microscope slide. The lymphocytes forming rosettes with StaCw were identical with cells expressing surface Ig studied by fluorescein‐isothiocyanate‐conjugated anti‐Ig. As a marker for T cells we used the acid α‐naphthyl acetate esterase (ANAE) histochemical marker. The cell smears were first stained for ANAE and subsequently counterstained to distinguish also cell morphology. The ANAE‐marker‐carrying cells were all included in the population of lymphocytes forming rosettes with sheep erythrocytes. Thus both T and B lymphocytes could be simultaneously identified from a single microscopic slide, and we therefore recommend the method for routine clinical work.
Immune Response in Asymptomatic Paraproteinemia
Authors: WEITS J. , de GAST G. C. , THE T. H. , MARRINK J. , MANDEMA E.
Published: August 2010

In a group of 20 patients with asymptomatic paraproteinemia, as judged after at least 3 years of follow‐up, the primary and secondary antibody response to Helix pomatia hemocyanin (HPH) was defective as compared with the response in controls. The class of antibody was assessed by mercaptoethanol (ME) treatment of serum. A lowered response was found not only in the total but also in the ME‐resistant (mainly 7S, IgG) antibody titer. Low anti‐HPH antibody titers were preferentially found in the patients with high serum paraprotein levels, whereas in half of the patients with low serum paraprotein levels a completely normal antibody response was found. No differences in the total or 7S anti‐HPH antibody response were found between patients with IgG, IgM, or IgA paraproteinemia. The polyclonal serum Ig levels were not predictive for the measured anti‐HPH response. The anamnestic diphtheria and tetanus antibody response was not different from that of controls.