art-6-1-21
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OCCLUSION AND TMJ
CONDYLOGRAPHIC RECORDING OF MASTICATORY
Original Articles
FUNCTION: EXPLORATIVE STUDY ON OCCLUSAL
PARAMETERS AND CHEWING PERFORMANCE WITH
NATURAL FOOD AND A STANDARD FOOD MODEL
Giulia Tanteri1a , Carlotta Tanteri1b , Gregor Slavicek2,3c*
1Private Practice - Studio Tanteri, Turin, Italy;
2Steinbeis Transfer Institute Biomedical Interdisciplinary Dentistry, Steinbeis University Berlin, DE-12489 Berlin, Germany;
3OREHAB-Minds GmbH, DE-70567 Stuttgart, Germany
a
MD, MSc, Specialist in Maxillofacial Surgery; e-mail: tanteri@tanteri.it; ORCIDiD: https://orcid.org/0000-0002-3765-7722
b
DDS, MSc; e-mail: carlotta.tanteri@gmail.com; ORCIDiD: https://orcid.org/0000-0001-5560-5574
c
MD, DDS, MSc, Director and Head, CEO and Head; e-mail: gregor.slavicek@stw.de; ORCIDiD: https://orcid.org/0000-0003-2454-4048
ABSTRACT https://doi.org/10.25241/stomaeduj.2021.8(1).art. 6
Introduction Loss of teeth defines oral health status and chewing abilities. Caries and periodontal disease
have been associated with systemic diseases, however they may contribute to cognitive impairment
too. Mastication assessment appears to possess broad significance, and is needed to create background
knowledge for chewing harmony. The aim of this study was to evaluate chewing performance and the
characteristics of condylographic recordings, during mastication of Natural Food (NF) and a Standard Food
Model (SFM), in subjects with different occlusal parameters.
Methodology Twenty-three adult subjects’ mastication was assessed with a standardized recording protocol,
when chewing onto SFM and NF in three different textures. Detailed occlusal characteristics, condylographic
recording data and condylographic patterns during mastication were all analyzed and compared.
Results Bilateral Crossbites, Missing Molars and Asymmetric Molar Class were related to higher disharmony
and transversal displacement during chewing. Missing and unreplaced molars showed dysfunctional
patterns and so did worn out occlusal surfaces. Molar Class alone did not prove to be a useful predictor in
chewing test results.
Conclusion Increasing evidence indicates that oral health has an impact on Individual and Public Health.
It is important to understand that oral health and its functional status are to be maintained during one’s
lifetime, and that preventive, therapeutic measures at all ages should have a common functional target to
grant neurobiological health as well as nutritional goals of Mastication. Further studies are needed to better
understand the relevance of additional parameters such as Occlusal Plane Inclination, Curve of Spee, and
three-dimensional asymmetries.
KEYWORDS
Mastication; Condylography; Axiography; Chewing Test; Occlusion.
1. INTRODUCTION quality of mastication and its efficiency are crucial
even beyond the individual ability to perform chew-
Throughout the history of medicine Mastication ing strokes and to swallow. Oral health has been
has triggered the interest of researchers due to its held responsible for, or related to, a number of
complexity, its functions and behavioral significance. systemic conditions. For instance, poor oral health
Mastication is the process by which food is broken has been investigated in the past as an independent
down by teeth into smaller pieces, mixed with saliva risk factor and association for systemic diseases
into a bolus and made suitable for swallowing. The such as myocardial infarction, coronary disease and
OPEN ACCESS This is an Open Access article under the CC BY-NC 4.0 license.
Peer-Reviewed Article
Citation: Tanteri G, Tanteri C, Slavicek G. Condylographic recording of masticatory function: explorative study on occlusal parameters and chewing
performance with natural food and a standard food model. Stoma Edu J. 2021;8(1):52-64
Received: February 21, 2021; Revised: February 27, 2021; Accepted: March 02, 2021; Published: March 04, 2021
*Corresponding author: Dr. Gregor Slavicek, MD, DDS, MSc, Director and Head, CEO and Head OREHAB-Minds GmbH, Zettachring 2, DE-70567
Stuttgart, Germany
Tel./Fax: +49-7307-24922-11; e-mail: g.slavicek@orehab-minds.com
Copyright: © 2021 the Editorial Council for the Stomatology Edu Journal.
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Original Articles
Figure 2. Quality of occlusal surfaces, from left to right: poor, average,
good.
Figure 1. Expected chewing pattern - example of right side chewing of
NF Carrot: ws displays shorter and steeper tracings as opposed to nws.
Movement is harmonic and superimposable, transversal aspects of
movement are contained.
Table 1. Inclusion criteria. hard and demanding quest which proceeded along
with the development of ad hoc apparatuses and
Inclusion criteria
recording devices. Studies by Lundeen and Gibbs
Subjects were considered for the study if the following from the 1980s showed that there are differences
conditions were met:
in chewing in relation to growth, and that they are
- any Gender related to changes in form and function which take
- good overall health status (no prescription drugs taken place during transition from infancy to adulthood
routinely, asymptomatic) (increase in the steepness of the articular eminence,
- no previous diagnosis of Temporomandibular Disorder development of the anterior tooth guidance, and
change from deciduous to permanent teeth). Adults’
- willingness to understand the procedure and give informed
chewing pattern has a midsagittal opening and
consent
wide lateral closing movements when observed
diabetes [1-3]. This whole issue has reached a higher from a dental perspective [9,10]. The quality of the
and wider awareness only in recent times, although occlusion, conditions such as Temporomandibular
earlier studies concerning these associations had Disorders (TMJ) and interferences in occlusion all
already highlighted the importance of maintaining affect mastication: the more the interferences the
a satisfactory oral and dental status for the good of longer the chewing time and the more atypical the
systemic health and for the consequences on Public pattern looks [11]. Regarding patterns, Lundeen and
Health [4]. Among the above-mentioned conditions, Gibbs studied mastication with the Replicator System
Dementia has more recently been related to oral [9,10]. The Replicator System was an electronic jaw-
health and chewing impairment. Because of its movement recorder that allowed to replicate all
vigorous onset in the elderly populations, and border and chewing movements while also being
because the world population is more and more able to examine ‘chewing casts’ from all views. The
represented by the elder age group, Dementia authors’ evaluations of the chewing patterns were
has become an increasingly important health and made on occlusal points (first molars and interincisal),
socioeconomic issue [5]. on both sides, as well as by tracking the joints.
It is fair to understand that, among other factors, the Studies concerning the masticatory patterns have
mere number of lost teeth defines not only one’s oral been described in previous works, the most notable
health status, but also his/her chewing abilities, with being the ones with the Sirognathograph first, and
subsequent forceful changes in diet, malnutrition, the Kinesiograph later on. This latter method can
and an inflammatory response which have all only identify movement of a single anterior point
been related to an increased risk of Dementia and with a magnet positioned on the lower arch, but it
Alzheimer’s Disease (AD). These emerging findings, has the possibility to study muscular activity through
besides harmony and good functioning of the Electromyography at the same time [12,13].
stomatognathic system, call for further studies on Researchers have also recognized a repetition and
mastication and on the significance of lost teeth, reproducibility of chewing patterns, with harmony
both for what concerns the number of missing also being a characteristic of a healthy chewing
teeth and what dental element in particular [6]. function and, if harmony is missing, along with
Teeth possess discrimination for direction of repetition and a scheme, then a dysfunctional masti-
forces, texture and hardness of foods, thanks to the cation is observed. Malocclusions such as unilateral
interaction between pulp-dentine-enamel units and crossbite have shown a peculiar subversion of
periodontal ligaments [7,8]. Studying mastication opening and closing direction which are substantially
and the stomatognathic system has shown to be a different to the expected chewing pattern: in these
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Original Articles Table 2. Exclusion criteria.
Exclusion criteria
Subjects were excluded if the following conditions were met:
- age below 18
- age above 70
- food allergy (nuts)
- vegetarian/vegan subjects
- hyperglycemia/diabetes
- permanence of deciduous teeth
- removable total/partial prostheses
- ongoing orthodontic treatment
- any dental extraction/dental surgery in the previous 6 months
- composite/filling on occlusal surfaces in the previous 6 months
- acute oral health issue (caries, odontogenic abscess, odontogenic phlegmon)
- acute craniofacial issue (trauma with/without fractures)
- acute/chronic pain of masticatory and facial muscles
- primary headaches
- chronic neck, shoulders or back pain (pain >3 months)
- previous brain injuries
- cleft palate/lips
- facial clefts
- impaired saliva production due to drugs or systemic disease
- mental illness
- visual impairments (sightless subjects)
- neurological disorder with impaired motor capabilities with/without medication
- neurological conditions affecting cranial nerves
- any condition influencing proper informed consent to participation in the study
- any conditioning affecting the sitting position in a dental chair
Figure 3. Standard Food Model jellies, from left to right: soft, medium and
hard texture.
cases, the mandible will first move medially during
opening and then laterally, so as to confront with
the ‘crossed’ surfaces of antagonist teeth. Moreover, Figure 4. Tool for calculating areas of condylographic tracings in sagittal,
this altered pattern has a narrower width and a cranial and frontal view. In this figure, the sagittal tracing was digitally out-
lined and in the bottom right-hand corner are the perimeter and the area
more vertical closing angle. If the ‘Functional Matrix’ of the right sagittal condylographic tracing. The same procedure was carried
of Moss is not to be forgotten, this supposedly has out for all planes (sagittal, cranial and frontal) on both sides for all chewing.
some effect on growing children, both structurally
and with respect to motor control, and it is the thus making the standardization for the masticatory
reason why unilateral crossbite can be looked at as a tests difficult. Natural foods that are mostly described
‘neuromuscular syndrome’ [12,14]. by authors are: peanuts, almonds, cocoa, carrots,
Some studies have explored human mastication hazelnuts, decaffeinated coffee beans and nuts
through chewing tests and their outcome. Kikui [16-21]. Previous experience with the limitations of
and colleagues for instance assessed comminution natural foods chewing tests brought about the need
of a jelly, claiming that it was a valid method for for an ideal food model for experimental, research
gathering relevant information from the number of and clinical testing. With this respect a Standard
pieces and their surface area. Food Model (SFM) was first developed, described
This better replicates in their opinion what actually and proposed by Slavicek in 2009 [22-26]. Such
occurs during effective chewing: crushing and an food model has been produced in a short cylindrical
increase in the surface area of food, so as to facilitate shape and three different hardnesses (A. Egger' Sohn,
reaction with digestive enzymes, decomposition, Süsswaren und Naturmittel GmbH., Mellergasse 4,
and the absorption of nutrients [15]. Some other A-1230 Vienna, Austria).
tests use natural foods as a material test, however Condylography as a method for evaluating mandi-
physical properties of natural foods vary and are bular movements has its predecessors dating as back
difficult to standardize. There are natural variations as the last decades of the 1800s. The first recordings
in size and texture which produce differences in the were reported by Ulrich and Walker, and invaluable
final outcomes. Besides, hardness is not constant, contributions to the study of hinge axis, Bennett
due to the various degrees of water incorporation movement, jaw tracking, articulator programming
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Table 3. Condylographic data collected directly from the recording software.
Software-retrieved data for analysis of Mastication
Maximum displacement (s) of the hinge axis (mm) for both the working side and the non-working side (ws and nws) assessed on
the sagittal plane
Sagittal Condylar Inclination SCI° (inclination of the hinge axis excursion) for both the working side and the non-working side (ws
and nws)
Table 4. Condylographic data calculated from tracings with the use of an additional tool.
Calculations for analysis of Mastication
Sagittal area for both working side and non-working side (mm2)
Transversal cranial area for both working side and non-working side (mm2)
Transversal frontal area for both working side and non-working side (mm2)
Ratio sagittal: cranial for both working side and non-working side
Ratio sagittal: frontal for both working side and non-working side
Figure 5. Molar Class Right and Left – Distribution Females.
and for diagnostic purposes have been made by correlation had been hypothesized even earlier,
Bennett, Eltner, Gysi, McCollum, Posselt, Messerman, when basic findings were retrieved highlighting
Bewersdorff, Jankelson, Lundeen, Alsawaf, Missert the fact that Dementia patients were more likely to
and Slavicek [27]. have a greater tooth loss [35,36]. However different
Caries, periodontal disease and systemic conditions studies and authors have aspired to study this
that can affect the periodontium, can all potentially relationship as a predisposing condition, similarly to
lead to tooth loss. Tooth loss can somewhat be what has been done with the correlation between
prevented and has therefore been the target for cardiovascular disease and periodontitis. A 5-year
Public Health measures, but nevertheless it is still prospective cohort study investigated the effect
common, especially within the ageing population of tooth loss on the development of Mild Memory
and in the lower socio-economic groups [28,29]. Impairment (MMI) among the elderly [31]. A study
What is mostly unforeseen or prevented, but is just on identical twins revealed that major tooth loss
as common, is Dementia, the most frequent being before the age of 35 was a significant risk factor for
Alzheimer’s Disease (AD). AD [32]. A study on a population of nuns, found that
A World Health Organization report from 2013 stated 9 or fewer remaining teeth were associated with an
that the total number of people with Dementia increased risk of Dementia [33].
worldwide in 2010 was estimated at 35.6 million Type 2 Diabetes patients were the target of a
and is deemed to almost double every 20 years, to prospective cohort study that showed that Demen-
65.7 million in 2030 and 115.4 million in 2050 [30]. tia and cognitive decline are associated with having
AD occurs because of environmental, genetic and no teeth [37]. Conversely, the presence of teeth,
vascular risk factors, yet nearly half of ADs do not or better, the preservation of natural teeth and
have a clear mutation or cause [6]. A relationship cognitive functioning have shown a significant posi-
between AD and tooth loss has been sought for at tive relationship [38]. Worse episodic memory has
least twenty years now, with publications focusing been assessed in other studies and it has been
on the transition from memory impairment to AD, correlated with tooth number, too [39]. Okamoto
on oral health in nursing homes, cohort studies and colleagues also reported about a survey study
and community homes for the elderly [31-34]. This that claimed that patients with MMI will more
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Original Articles
Figure 6. Molar Class Right and Left – Distribution Males.
likely progress into AD as opposed to other types and memory [8,42-46]. A pilot study by Elsig allowed
of dementia, thus making MMI (examined through to point out a difference between the number of
the Mini-Mental State Examination - MMSE) a good remaining teeth and chewing efficacy in Dementia
time-frame for evaluations of this kind [40]. In the patients, thus further encouraging the performance
Fujiwara-kyo study a population of 3696 healthy of routine chewing tests besides tooth count in
residents over the age of 65, was observed from geriatric evaluations [47]. Mastication and its study
2007 to 2012. Among these, 2486 underwent follow- appear to possess significance both individually,
up examination and 2335 were included in the final in terms of prediction of disease or its risk, for its
analysis (only cognitively intact or MMI subjects). educational value, and in order to create a wider
This very powerful and well-designed study showed database for chewing patterns and unfavorable occ-
that tooth loss and worse cognitive performance lusal features, which will enable to fulfill the afore-
are indeed correlated, and that absence of tooth mentioned purposes.
loss and preservation of the patients’ baseline status The aim of this study was to assess the characteristics
meant no increase in risk of MMI [31]. of condylographic tracings, during mastication of
Possible reasons for the association between memory natural food (NF) and a standard food model (SFM),
disorder and tooth loss have been highlighted not in subjects with different occlusal parameters.
only in the Fujiwara-kyo paper: the existence of an Based on the existing literature, the purpose was
inflammatory status related to periodontal disease to evaluate whether condylography was suitable
which caused tooth loss; genetic factors related to for tracking mastication at the temporomandibular
both MMI and periodontal disease; and a decrease joint (TMJ), to evaluate whether condylography
in sensory receptors function. An observational could reliably provide a clear tracing aspect working
study published in 2015 aimed at drawing some (ws) versus non-working side (nws) with the ws
associations between tooth loss and Dementia from being steeper, straighter and shorter as opposed to
the late 1960s onwards [41]. the nws (see Fig. 1), if disharmony or subversion of
The hypothesis behind this retrospective analysis the abovementioned aspect of ws and nws for some
of a cohort of women was that tooth loss was an occlusal features (flat occlusal surfaces, missing
expression of some proinflammatory activity and teeth,...) and food properties.
that there was a correlation between the number
of teeth and Dementia. Mastication influences the 2. MATERIALS AND METHODS
activity in the cerebral cortex, stimulating cognitive
function and preventing brain degradation. Twenty-three adult subjects’ mastication was asse-
Rhythmic movements, and this may be one reason ssed by means of condylography with a standar-
why sports have a similar beneficial effect, increase dized recording protocol, when chewing onto SFM
blood flow especially in the prefrontal cortex and and NF in three different textures (for SFM: hard,
the hippocampus, where learning and memory medium, soft; for NF: salad leaf, carrot slice, nut). The
performance reside [31,38]. study protocol followed the ethical guidelines of the
Thorough dissertation on the role of chewing, Declaration of Helsinki, and informed consent prior
hippocampal, reticular formation and somatosensory to recording was acquired from all subjects (see Tabs.
associations is not the scope of this paper, however 1 and 2). Sagittal first molar relationship (Class 1, 2 and
impoverishment of chewing abilities and function 3) was recorded for each subject and each side (right
through alteration in number or quality of occlusal and left). Asymmetric molar classes were included in
determinants (extraction or milling of molars) and the data collection. The presence of a Clear Buccal
a long-term soft-diet feeding, can inhibit learning Intercuspation was checked according to the clinical
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Figure 7. Mann-Whitney U Test results for differences in sagittal (xz plane Figure 8. Mann-Whitney U Test results for differences in sagittal (xz plane
of condylography) to transversal (yz and xy planes) ratios of chewing of condylography) to transversal (yz and xy planes) ratios of chewing
tracings for SFM and NF in Asymmetric Molar Class (Y/N). tracings for SFM and NF in Asymmetric Molar Class (Y/N).
assessment of a distinct 1:2 vestibular relationship underwent a condylographic recording session
between upper and lower arches. Other sagittal and during which a standard recording and a chewing
transversal intermaxillary dental relationships were recording were performed. The condylography was
recorded as well: open bite (when overbite<0 mm), carried out by using an electronic recording system
deep bite (when overbite>4 mm), bilateral crossbite, for jaw movements (Cadiax Diagnostic GAMMA
monolateral crossbite, scissor bite. The presence Dental, ®GAMMA med. wiss. Fortbildungs GmbH,
and location of missing teeth and prosthodontic/ Josef Brennerstr. 10, A-3400 Klosterneuburg, Austria).
conservative restorations were recorded too. One trained investigator performed all recordings. A
Occlusal surface characteristics were evaluated as paraocclusal clutch was applied, the hinge axis was
Good, Average or Poor based on the investigators’ localized and classic condylographic recording of
assessment on overall tooth wear (Fig. 2). All subjects movements would take place before the chewing
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Original Articles Table 5. Quality of occlusal surfaces (right side). Table 6. Quality of occlusal surfaces (left side).
# of subjects # of subjects
Poor 9 Poor 8
Average 6 Average 8
Good 8 Good 7
recording session. A previously developed and was detected in 5 subjects (21.7%). See Gender
described Standard Food was used in three different distribution in Figs. 5 and 6. The Open Bite was
textures (soft, medium and hard) (A. Egger´ Sohn, present in 3 subjects overall (13%), whereas Deep
Süsswaren und Naturmittel GmbH, Mellergasse 4, Bite was found in 30.4% of subjects (7 probands).
A-1230 Vienna, Austria). The shape of these jellies The Open bite was present in 2 cases of Class 1
was cylindrical and the size was 10x20 mm (Fig. 3). molar relationships (16.67% of all class 1) and in 1
The recordings were strictly performed for 18 seconds, case (11.11%) with molar class 2, both for the right
on each side (right, left and bilateral chewing), side. For the left side, the open bite was present in 2
for each texture of jellies and for each type of natural cases (18.2%) in Molar Class 1 and in 1 case (16.7%)
food. Eighteen seconds were mandatory because for class 2. No open bite was related to Molar Class
of the maximum recording time the software could 3 on either side. The Deep Bite was mostly present
host. in Class 2 right side where it represented 44.44% of
The participants were instructed to chew each food all class 2 subjects (25% for Class 1 right side, 0% for
on the right side, on the left side and bilaterally, Class 3 right side).
and break the food in as many pieces as possible For the left Molar Class 1, 2 and 3 the presence of
without swallowing, since the food particles had to the Deep Bite was present in 27.27%, 33.33% and
be collected at the end of each chewing cycle for 33.33% of cases.
separate evaluation. A bilateral Crossbite was detected in 17.39% of
A resting time of at least 30 seconds was allowed probands (4 cases) and a monolateral crossbite
between recordings. The recording hardware was was present in 2 cases only (8.7%). No proband had
then removed, and the proband was asked to scissor bite.
identify and score discomforts so that they could be The quality of the Occlusal Surfaces (Tabs. 5 and
collected and stored within the database. 6) was rated as poor for the right side on 9 counts
For each proband the maximum ‘s’ displacement (39.1%), and on 8 counts for the left (34.8%).
of the Temporomandibular Joint Hinge Axis during A Clear Buccal Intercuspation was found for 14
the 4 baseline movements and during the chewing subjects (60.9%). Missing Premolars were found in
sequences was taken from the software analysis for one proband only (4.3%) with no edentulous gap
both right and left condyle in millimeters (s, mm). For between tooth 1.4 and tooth 1.6. Missing Molars
each chewing sequence, for SFM and NF, the data in were observed in 6 cases (26.1%). Distal Restorations
Table 3 were collected from the appropriate tool in were present in 7 subjects (30.43%).
the software and stored. For each chewing sequence,
SFM and NF, the data in Table 4 were retrieved with 3.2. Statistical Analyses
the aid of the online tool SketchAndCalc™ (iCalc Inc, 3.2.1. Condylographic Tracings for Working and Non-
2017 Elliott Dobbs, www.sketchandcalc.com) and Working Sides with SFM and NF
used for further calculations (Fig. 4). For both food types, the working sides’ tracings (s,
All Descriptive Statistics and Tests were carried out mm) were shorter than the non-working sides (SFM
with IBM SPSS Statistics for Windows, Version 24.0 ws mean 4.9 mm nws 6.8 mm; NF ws mean 3.6 mm
AND 25.0 Armonk, NY IBM Corp. (Released from nws 5.3 mm; paired t test set at 95% CI p=0.000 for
2016). SFM and p=0.000 for NF). The difference by hardness
on both ws and nws is not detectable. Nevertheless,
3. RESULTS all SFM compared to the NF s traits were significantly
different, with SFM having larger displacements in
3.1. Descriptive Analysis of Subjects mm (SFM s mean 5.75 mm; NF 4.56; paired t test set
There were 14 females (60.87%) and 9 males (39.13%). at 95% CI p=0.000).
The subjects’ age ranged from 18 to 64 years of age 3.2.2. Condylographic Tracings’ Distinctive Path
(mean age 37.74 ±12.53). Inclination SCI° for Working and Non-Working Sides
The Molar Class for the right side was found to be with SFM and NF
Class 1 in 52.17% of subjects, Class 2 in 39.13% For the SCI° (path inclination) SFM ws and nws were
and Class 3 in 8.70% of probands. For the left side, compared, with the nws showing a flatter inclination
the percentages were 47.83%, 26.09% and 26.09% as expected (mean ws=61.12°, mean nws=53.31°),
respectively. For both sides Molar Class 1 was nearly which was statistically different from the steeper
half of the total and an Asymmetric Molar Occlusion inclination of the ws as tested with a paired t test
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Figure 9. Male 31 yo, Asymmetric Molar Class (Right side Class 1, Left side Class 2).
set at 95% CI (p=0.000). Since the distribution of 4. DISCUSSION
these data was not normal for SCI° SFM medium
Left chewing and SFM hard Left chewing, a non- As there is increasing evidence indicating that
parametric test was also carried out (Wilcoxon oral health has an impact on Public Health issues,
Signed Rank Test with significance level at 0.05, and not solely on Individual Health, it is important
p=0.01 and 0.003 respectively). The NF chewing SCI° to understand and maintain the mastication tool
were also compared for ws and nws by means of a properly fitted for its neurobiological objectives as
parametric and a non-parametric test, since even well as nutritional ones.
here the normal distribution of data was not the case What is expected from an ‘ideal’ mastication is, in
at all times. Both the paired t-test and the Wilcoxon this respect, of the utmost importance. If teeth are
Signed Rank Test allowed to highlight a significant to be seen as refined, precise and sophisticated
difference in steepness of condylar path inclination. proprioceptors, then the scientific community’s
3.2.3. Condylographic Distinctive Chewing Pattern task is to test, assess and restore them accordingly.
for Working and Non-Working Sides with SFM and This is the assumption behind this work, which is an
NF offspring of previous ones which aimed at studying
The presence of a Distinctive Chewing Pattern was human mastication quantitatively and qualitatively
tested against the Quality of Occlusion Surfaces [22-26]. The Reader might want to know that other
Right and Left but no significant correlation was recorded condylographic parameters and chewing
observed (χ2 p=0.343 right side p=0.577 left side). scores had to be kept out of this publication for
A significant correlation was observed instead for space reasons (number of particles chewed, scores,
the variable Missing Molars and the absence of a number of chewing strokes, rotational angle
Distinctive Pattern (Fisher Exact Test p= 0.006). The GAMMA° according to the different food hardness).
variable Gender and Presence of Distal Restorations The population of the present study encompassed
did not yield a statistically significant result (Fisher diverse occlusal features, but it was a small one,
Exact Test p= 0.064). nevertheless it allowed the Investigators to set some
3.2.4. Condylographic Chewing Tracings’ Areas and ground for new hypotheses for future studies, and
Ratios with SFM and NF make this an explorative study on mastication and
The mere assessment of areas in mm2 showed few its recording. Females showed more absence of a
statistically significant results, but an observed clear intercuspation as opposed to males, and they
tendency to have nws with bigger areas than ws for had a poorer occlusion, more occlusal restorations
Molar Class 1 and 2. and, most importantly, less presence of a distinctive
However, assessment through ratios allowed the chewing pattern. Yet, the females here were the
Authors to expressly identify the predominance group with the most frequent ‘ideal’ Class 1 occlusion
of transversal movement during chewing over the (81%), and all Class 1s overall have 72% of clear
sagittal one across all SFM and NF chewing (right side buccal intercuspation. As elsewhere highlighted, this
chewing, left and bilateral). Statistically significant combination of findings suggests that the Molar
results were retrieved for the variables Quality Class alone is not a sufficient indicator at all for an
of Occlusion (poor, average, good Kruskal-Wallis ideal or functional mastication [48]. Monolateral
max p=0.42), Bilateral Crossbite (Mann-Whitney U Crossbite cases were too few to infer correlations.
max p=0.048), Missing Molars (Mann-Whitney U Condylography really fulfilled the task of showing
max p=0.041), Clear Buccal Intercuspation (Mann- geometrical features of working and non-working
Whitney U max p=0.040), Distal Restorations (Mann- sides for SFM and NF: for both food types the working
Whitney U max p=0.041) and most importantly sides were in fact shorter than the non-working sides.
Asymmetric Molar Class. This comes helpful in research settings in that SFM,
This latter variable in particular, gave significant which is not a vegetable but is still food, is generally
results for all SFM hardness and for the NF too (for chewed with the expected pattern that NF normally
space reasons only these results are displayed in shows, but it has the potential to stress and highlight
Figs. 7 and 8). characteristics which small, easily chewed NFs may
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Original Articles
Figure 10. Condylographic Recording during chewing of SFM and NF (only soft and hard SFM, and salad leaf chewing are displayed for space reasons)
by proband in Figure 9. Non-harmonic left side tracings with a very wide transversal component can be observed for SFM and NF chewing.
not have the power to exhibit. Much like many other the single areas retrieved for all foods, all sides and
clinical tests which can be performed at rest, but are all planes (sagittal, frontal and cranial), but ratios
sometimes required to be performed under physical between the sagittal plane and the transversal
or drug-induced stress to really recreate a condition planes were also calculated, so as to minimize the
or provoke one, the SFM chewing test might prove effect due to individual sizes, and enhance the more
the treadmill test for the masticatory system. The robust meaning of sagittal to transversal ratios. As
results with nuts and carrots have shown in fact that the ratio decreases, both for the sagittal:frontal and
every proband can chew on them with no trouble the sagittal:cranial dimensions, then the transversal
regardless of the occlusal quality, missing teeth quantity of movement becomes predominant over
and so forth. One single salad leaf is instead more the sagittal one. Graphical representation of areas in
demanding, since it can be properly torn only when mm2, divided by ws and nws and molar class right and
the occlusal quality is maintained, for it requires left, was difficult to interpret at a first glance and no
closeness of upper and lower teeth which get to particular difference or feature stood out. When the
slide on their buccal and lingual slopes. If these chewing data were assessed through the ratios one
are lost then a grinding movement between flatter can see that the ‘good’ quality of the occlusion right
surfaces occurs and this sets the basis for a more had bigger nws ratios (more sagittal component) for
horizontal/transversal movement rather than a SFM soft and medium (this difference was not visible
vertical/sagittal one. All lengths ‘s’ of the SFM sagittal for SFM hard), as compared to the average and poor
tracings were numerically bigger than all lengths of right occlusions (more transversal component). A
NF sagittal tracings and this might be the effect of similar trend could be seen for the nws ratios for the
the properties of SFM (standard size for instance). left qualities of occlusion, but not for every single
For SCI° (condylar path inclination), SFM ws and nws ratio and hardness of SFM.
were compared, nws showing a flatter inclination as The ws ratios were smaller in poor right occlusions
expected, which was statistically different from the as compared to the ws ratios of the the average and
steeper inclination of the ws. The same held true for good occlusions, supporting the hypothesis that
NF. The assessment of the chewing tracings’ areas even in working sides there is a more transversal
was the most demanding and most interesting component in flatter occlusal qualities. The same
chapter in this explorative study. Not only were could be seen for the left qualities of occlusion.
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Similarly, when looking at the NF ratios, the poor 5. CONCLUSIONS
Original Articles
occlusions right and left had smaller ratios compared
to average occlusion, but not as much compared As highlighted in previous works, the geriatric
to the good occlusion where differences were population is highly affected by cognitive impair-
mostly seen in the sagittal: cranial plane ratios. This ment and more exposed to pureed, blended and
sagittal:cranial ratio looks especially useful when mashed food. At times it is because dysphagia is
looking at differences in NF, since the ‘s’ displacement present, however in many facilities prescription of
is already significantly shorter in NF than SFM, and pureed food is offered to many without real reasons
perhaps more understandable on the cranial plane behind it. MTF (Modified Texture Food) is often
instead of the frontal one. For a similar reason ws poorer in nutritional content and not very accepted
ratios in NF show little or inconsequent differences and therefore eaten less despite the apparent
among the various occlusal qualities, since the range easiness in swallowing it [49].
of the areas on working sides is already quite small Like others, Dementia is a delicate Public Health
in mm2. Another difference between the ratios can issue in that it directly affects patients and families,
be detected between the ws ratios of SFM and NF it requires a very demanding set of measures to
in subjects who have distal restorations and subjects satisfy the need and quality of life of both, and
who do not have distal restorations (NF nut is the it tackles many aspects of preventive medicine.
only food which does not show this as clearly), with Needless to say, it is a financial dilemma for many
the Distal Restoration Group displaying smaller and it encompasses a very transversal series of
ratios (therefore a more transversal component). The medical specialties, odontology being one of the
same observation could not be made for the nws. most recent. Prevention is crucial as medical therapy
Probands without Clear Buccal Intercuspation is at present unable to address Dementia, resulting
display smaller ratios for NF in the nws than probands in a frustrating series of events which lead to smaller
with Clear Buccal Intercuspation. Ws show the same chance of detecting other diseases, smaller response
difference but only in sagittal: cranial evaluation. The to treatments in general, reduced life expectancy
above-mentioned observations have been tested and uncontrolled disease progression [6].
(for areas and ratios, for SFM and NF) and differences A better understanding of the significance and role
have been found to be statistically significant. All of dental elements as singular units in neurological
differences in the sagittal and transversal areas in modulation could empower knowledge about dental
mm2 provide food for thought in that they indicate a risk factors and perhaps make them modifiable, and
purely numerical size discrepancy which could hide this would raise new awareness to be transferred to
or be related to other ‘size’ parameters not taken into researchers, physicians and most importantly the
account in this study. Anyway, it is the difference or population. Bearing this in mind, proper mastication
even inversion of the sagittal to transversal ratios, in should be guaranteed to avoid malnutrition in
Bilateral Crossbite, Missing Molars and Asymmetric those populations where cognitive impairment
Molar Class subjects, that really supports the idea has already occurred, and to at least maintain their
that these occlusal features and malocclusions are general health status. Studies on the chewing effi-
related to a higher transversal displacement during ciency of these very populations have shown that
chewing cycles, usually with the non-working side Dementia patients eat slowly and therefore less, have
performing very wide movements (see Figs. 9 and 10). uncoordinated masticatory activities with chewing
The findings in this explorative study suggest a strokes accompanied by facial mimic movements,
number of considerations. Transveral stability in and most importantly that it is very hard to assess
occlusion (granted by one-to-two tooth contacts their chewing performance. At the same time, it is
sagittally, and by lingual occlusion transversally) by now widely recognized that chewing positively
needs to be looked at and restored/provided for affects cognitive functions with respect to memory
accordingly. The quality of occlusion is a crucial and learning, and that masticatory hypofunction is
feature: restorative procedures which aim at restoring independently related to cognitive impairment [50].
quadrants or single elements in flat occlusions need Mastication studies have historically been conducted
to be looked at critically. Missing and unreplaced by dental researchers to highlight features and risk
molars correlate with dysfunctional chewing patt- factors related to Temporomandibular Disorders, to
erns. Molar Class has already shown little signifi- understand human stress-management strategies,
cance and therefore it is not a good indicator for or even to assess orthodontic treatments, full den-
describing malfunctions or chewing differences. tures, prosthodontic restorations and functions
Some of the unexpected chewing patterns may be like speech and bruxism. More recent evidence on
due to undetected skeletal asymmetry of the cranial Public Health impact of mastication urges scien-
base which does not necessarily correlate with an tists to identify occlusal characteristics which
asymmetry in molar class. SFM and condylographic interfere with a healthy masticatory function, so
recording can be exploited as a stress test for the as to pinpoint preventive measures or minimize
detection of incapability in chewing stiff meats or health impairments. The findings presented here
other nutrient food. are supported by the extensive previous works
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of authors who approached their research with instance) and even though some differences were
Original Articles different apparatuses. This study’s aim was to identify statistically significant, a higher number of cases,
a correlation between specific occlusal features and a more robust study design and a less numerous
what is so far known about the characteristics of choice of outcomes might allow to draw more
‘dysfunctional chewing patterns’. The results from powerful conclusions and influence clinical work.
chewing tests by means of a Standardized Food in
combination with condylographic studies should CONFLICT OF INTEREST
be promoted in the future to better understand The authors declare no conflict of interest.
chewing patterns, but most importantly to make a
statement concerning which occlusal characteristics ACKNOWLEDGMENTS
are to be detected early, which are to be avoided in
rehabilitation procedures, and which goal should The Authors wish to thank Dr. Eugenio Tanteri for providing
occlusion therapy pursuit. In the near future, indivi- hardware for the study.
dual compensatory capabilities should not be called
upon to excuse poor occlusal therapies, and other AUTHOR CONTRIBUTIONS
conditions within the psychosocial sphere should
no longer justify a sudden or progressive onset of GT: contributed to the study design, protocol, data gathering,
stomatognathic symptoms. This study’s limitations analysis, manuscript preparation. CT: contributed to the study
are surely related to the small number of cases. The design and manuscript revision. GS: contributed to the concept,
study design did not require a minimum number of study design, analysis and interpretation of data.
occlusal patterns (such as monolateral crossbite for
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Giulia TANTERI
MD, MSc, Specialist in Maxillofacial Surgery
Private Practice - Studio Tanteri
Turin, Italy
CV
Dr. Giulia Tanteri, MD, MSc, graduated in Medicine and Surgery at the University of Turin, Turin, Italy where she subsequently
completed her Oral and Maxillofacial Surgery specialization. Her activity is primarily dedicated to TMJ disorders diagnostics
and treatment. Her research interests have focused on the instrumental assessment of the stomatognathic system and its
rehabilitation, head and neck reconstructive surgery and oral surgery. She currently collaborates with the Steinbeis Transfer
Institute for Biomedical Interdisciplinary Dentistry (Stuttgart, Germany) and works as a private practitioner in Turin, Italy.
Questions
1. Tooth loss predicts the development of MMI among the elderly:
qa. Absence of tooth loss and preservation of the patients’ baseline status meant no increase in risk of MMI;
qb. In case of periodontitis-induced tooth loss, cognitive function is worsened;
qc. If teeth are lost before the age of 50;
qd. None of the answers is correct.
2. Mastication influences the activity in the cerebral cortex:
qa. Through blood flow increase especially in the prefrontal cortex and the hippocampus, where learning
and memory performance reside;
qb. Through increase of the number of neurons and synapses;
qc. Mastication and physical activity are rhythmic movements and have no beneficial effects on learning
and spatial memory;
qd. Regardless of the presence of teeth.
3. In geriatric evaluations:
qa. Tooth count is the main predictive factor which should be assessed since patients are already being fed
on mashed food;
qb. Tooth count and chewing performance should both be considered;
qc. Chewing performance only has relevance as a stress test for the Stomatognathic System;
qd. Chewing performance and tooth count are both to be considered after the onset of dementia.
4. Recording of a healthy chewing function should possess:
qa. Symmetry between working and non-working sides;
qb. A recognizable preferred chewing side;
qc. No specific pattern is relevant, as long as the subject is asymptomatic;
qd. Repetition, reproducibility and harmony in all projections, with a distinctive scheme for working and
non-working sides.
64 Stoma Edu J. 2021;8(1): 52-64 pISSN 2360-2406; eISSN 2502-0285