Intraoral Manipulation Research Articles

The intraoral permeability measurement as a screening for artifact formation by orthodontic products in MRI.

Metal dental products lack precautionary statements regarding MR compatibility due to an exemption in the labelling obligation. Hence, it is difficult for radiologists to decide whether to remove fixed metal objects in patients prior to MRI. Asolution could be the direct determination of the magnetic permeability (µr) as adecisive material-related predictor of artifact formation and other interactions. Thus, the applicability of an industrially used measurement device as ascreening instrument and the relevance of the manufacturer's application restrictions in vitro and in vivo were tested. Precision and trueness were tested using self-made test objects with different dimensions and different permeability. To clarify whether the measurement results are affected by the remanence (BR) induced in the objects, 28brackets of different materials were exposed to aweak and astrong external magnetic field and the magnetic flux density before and after these exposures was compared. The clinical test was performed on avolunteer with an orthodontic appliance experimentally composed of brackets with different levels of magnetic permeability (µr). Validity and intra- and interrater reliability were calculated using two rater groups consisting of four dentists and four medical-technical radiology assistants (MTRA), respectively. With coefficients of variation below 0.14%, precision was excellent regardless of object surface and size. Trueness was high on objects with µr ≤ 1.002, and decreased with increasing µr, for which size-dependent correction factors were calculated. Intra- and interrater reliability and validity were excellent and independent of professional intraoral manipulation experience. The permeability measurement allows for avalid and reliable determination of the magnetizability of intraoral metal objects.When used as ascreening tool to detect nonartifact-causingobjects, no correction factor needs to be calculated.For the first time, it offers radiologists adecision support for the selective removal of only the highly permeable components of the multiband apparatus.

Intraoral Hirudotherapy for Venous Congestion following Free Flap Head and Neck Reconstruction: Novel Intraoral Technique

Intraoral hirudotherapy is traditionally used for venous congestion following head and neck free flap reconstruction. Many institutions and healthcare teams have been reluctant to use intraoral leech therapy due to risks such as migration into the airway, increased infection from intraoral manipulation, and patient discomfort. Several protocols recommend blocking the path to the oropharynx via gauze or leaving a tracheotomy in place to protect the airway. This report pre­sents a novel technique for intraoral hirudotherapy that is safe and simple for treatment of free flap venous congestion. The base of a clear cup or a plastic lid is utilized, and the leech is attached onto the inside of the lid with 2 sutures near each end. Several cups with leeches attached are made at a time to reduce delay and difficulty of application by less experienced clinical staff. The leech is then applied onto the compromised flap and then simply removed once it has unlatched from the flap. This method allows the leech to be applied with ease by multiple members of the healthcare team, decreases the need for intraoral manipulation, and reduces the risk of migration into the aerodigestive tract. Future prospective studies are warranted to assess the efficacy of this technique.

Impact of pandemic COVID-19 outbreak on oral mucositis preventive and treatment protocols: new perspectives for extraoral photobiomodulation therapy.

This communication discusses the current challenges of oral mucositis (OM) management during the pandemic COVID-19 outbreak and reflects about an extraoral photobiomodulation protocol as an optimal alternative for preventing and treating OM in advanced cancer patients while minimizing the risk of infection by avoiding intraoral manipulation.

English

English

Perturbed oral motor control due to anesthesia during intraoral manipulation of food

Sensory information from periodontal mechanoreceptors (PMRs) surrounding the roots of natural teeth is important for optimizing the positioning of food and adjustment of force vectors during precision biting. The present experiment was designed to test the hypothesis; that reduction of afferent inputs from the PMRs, by anesthesia, perturbs the oral fine motor control and related jaw movements during intraoral manipulation of morsels of food. Thirty healthy volunteers with a natural dentition were equally divided into experimental and control groups. The participants in both groups were asked to manipulate and split a spherical candy into two equal halves with the front teeth. An intervention was made by anesthetizing the upper and lower incisors of the experimental group while the control group performed the task without intervention. Performance of the split was evaluated and the jaw movement recorded. The experimental group demonstrated a significant decrease in measures of performance following local anesthesia. However, there was no significant changes in the duration or position of the jaw during movements in the experimental and control group. In conclusion, transient deprivation of sensory information from PMRs perturbs oral fine motor control during intraoral manipulation of food, however, no significant alterations in duration or positions of the jaw during movements can be observed.

Comparison of three different insertion techniques with LMA-Unique™ in adults: results of a randomized trial

Abstract Background The triple airway maneuver insertion technique allowed faster insertion of the LMA. This study compared three different insertion techniques of the laryngeal mask airway-Unique™. Methods One hundred and eighty ASA I–II patients aged 18–65 years were included into the study. Patients were randomly allocated to the standard, rotational and triple airway maneuver (triple) group. In the standard group ( n = 60), the LMA (Laryngeal Mask Airway) was inserted with digital intraoral manipulation. In the triple group ( n = 60), the LMA was inserted with triple airway maneuver (mouth opening, head extension and jaw thrust). In the rotational group ( n = 60), LMA was inserted back-to-front, like a Guedel airway. Successful insertion at first attempt, time for successful insertion, fiber optic assessment, airway morbidity and hemodynamic responses were assessed. Results Successful insertion at the first attempt was 88.3% for the standard, 78.3% for the rotational and 88.3% for the triple group. Overall success rate (defined as successful insertion at first and second attempt) was 93% for the standard, 90% for the rotational and 95% for the triple group. Time for successful insertion was significantly shorter in the triple group (mean [range] 8.63 [5–19]s) compared with the standard (11.78 [6–24]s) and rotational group (11.57 [5–31]s). Fiber optic assessment, airway morbidity and hemodynamic responses were similar in all groups. Conclusions Rotational and triple airway maneuver insertion techniques are acceptable alternatives. Triple airway maneuver technique shows higher overall success rates and allows shorter insertion time for LMA insertion and should therefore be kept in mind for emergent situations.

A novel implantable device for the treatment of obstructive sleep apnea: clinical safety and feasibility.

ObjectiveMany cases of obstructive sleep apnea (OSA) involve collapse of the tongue base and soft palate during sleep, causing occlusion of the upper airway and leading to oxygen desaturation. Existing therapies can be effective, but they are plagued by patient adherence issues and the invasiveness of surgical approaches. A new, minimally invasive implant for OSA has been developed, which is elastic and contracts a few weeks after deployment, stabilizing the surrounding soft tissue. The device has had good outcomes in preclinical testing; this report describes the preliminary feasibility and safety of its implementation in humans.Patients and methodsA prospective, multicenter, single-arm feasibility study was conducted. Subjects were adults with moderate-to-severe OSA who had previously failed or refused conventional continuous positive airway pressure treatment. Intraoperative feasibility data, postoperative pain, and safety information were collected for a 30-day postoperative period.ResultsForty subjects participated (37 men, three women; average age of 46.1 years); each received two tongue-base implants and two soft-palate implants. Surgical procedure time averaged 43 minutes. Postsurgical pain resolved readily in most cases; at 30 days post implantation, <20% of subjects reported pain, which averaged less than two out of ten. Adverse events were generally the mild and expected sequelae of a surgical procedure with general anesthesia and intraoral manipulation. The device was well tolerated. Implant extrusions were reported with soft-palate implants (n=12), while tongue-base implants required few revisions (n=2). Quantitative and qualitative sleep effectiveness outcomes (including full-night polysomnographic and quality-of-life measures) will be presented in a subsequent report.ConclusionImplantation of the device was feasible. Although a relatively high rate of extrusions occurred in the now-discontinued palate implants, tongue-base implants were largely stable and well tolerated. The minimally invasive and maintenance-free implant may provide a new alternative to higher morbidity surgical procedures.

Prosthetic Rehabilitation with Collapsible Hybrid Acrylic Resin and Permanent Silicone Soft Liner Complete Denture of a Patient with Scleroderma‐Induced Microstomia

Scleroderma is an autoimmune multisystem rheumatic condition characterized by fibrosis of connective tissues of the body, resulting in hardening and impairment of the function of different organs. Deposition of collagen fibers in peri-oral tissues causes loss of elasticity and increased tissue stiffness, resulting in restricted mouth opening. A maximal oral opening smaller than the size of a complete denture can make prosthetic treatment challenging. Patients with microstomia who must wear removable dental prostheses (RDPs) often face the difficulty of being unable to insert or remove a conventional RDP. A sectional-collapsible denture is indicated for the prosthetic management of these patients, but reduced manual dexterity often makes intraoral manipulation of the prosthesis difficult. A single collapsible complete denture is a better choice for functional rehabilitation of these patients. This clinical report describes in detail the prosthodontic management of a maxillary edentulous patient with restricted mouth opening induced by scleroderma with a single collapsible removable complete denture fabricated with heat-polymerized silicone soft liner and heat-cured acrylic resin. The preliminary and secondary impressions were made with moldable aluminum trays by using putty and light-body poly(vinyl siloxane) elastomeric impression material. The collapsed denture can be easily inserted and removed by the patient and also provides adequate function in the mouth.

Application of a New Material (β-TCP/Collagen Composites) in Extraction Socket Preservation: An Experimental Study in Dogs

A bone defect model simulating an extraction socket with buccal dehiscence was designed to investigate the usefulness of a composite of beta-tricalcium phosphate (β-TCP) and a collagen sponge, β-TCP/collagen (TCP/Col) for socket preservation. Following the extraction of the maxillary second and third premolars of 13 beagle dogs, a bone defect with buccal dehiscence (5 × 3 × 7 mm) was prepared. The defects were filled with either TCP/Col, ?-TCP, collagen, or left intact (control) and evaluated at 4 and 8 weeks after surgery. A total of three micro-computed tomography (micro-CT) images were selected, and the area size occupied by the newly formed bone and residual TCP was measured. Newly formed bone and residual TCP in the bone defect site of the specimens was also measured and evaluated. No evidence of postoperative infection was found in all cases. At 4 weeks after surgery, the TCP granule was retained in the bone defects and active bone formation was observed in the TCP/Col group and the β-TCP group, whereas in the collagen and the control groups, connective tissue grew into the defect. In the TCP/Col and β-TCP groups, morphologically well-preserved alveolar ridges were observed; most TCP granules grafted in the defects were resorbed and only a few residuals were evident at 8 weeks after surgery. These results exhibited that the TCP/Col composites could sufficiently maintain bone width and height for the preservation of the extraction socket with buccal dehiscence while preventing epithelial in-growth. In addition, TCP/Col in an easily handled spongeous form could provide a better intraoral manipulation capability than TCP granules alone and was considered to be suitable as a bone grafting material used for alveolar ridge preservation.

Alterations in intraoral manipulation and splitting of food by subjects with tooth‐ or implant‐supported fixed prostheses

Sensory information provided by the periodontal mechanoreceptors (PMRs) is used by the nervous system to optimize the positioning of food, force levels, and force vectors involved in biting. The aim of this study was to describe motor performance during a novel manipulation-and-split task and to assess the extent to which control of this performance involves information from the PMRs. A total of 10 subjects with natural teeth, 10 with bimaxillary tooth-supported fixed prostheses (TSP) and 10 with bimaxillary implant-supported fixed prostheses (ISP) (61-83 [mean 69] years of age) were asked to perform an intraoral manipulation-and-split task that involved positioning a spherical chocolate dragée between the front teeth and then splitting it into two parts of equal size. The vertical jaw movement, sound of food cracking and masseter muscle activity were monitored during this task and the accuracy of the split was evaluated. The group with natural teeth was significantly better than the other groups at splitting the candy with high precision. The jaw movements were similar between groups, but the contact phase prior to the split was significantly longer for those with natural dentition. The present findings support the conclusion that the nervous system collects rich information about contact between the teeth and food from the PMRs prior to powerful jaw action. Impairment (TSP) or absence (ISP) of this information alters motor behavior and impairs performance during the natural biting task employed here.

Insertion of LMA Classic™ with and without digital intraoral manipulation in anesthetized unparalyzed patients

Background:The standard recommended insertion technique for LMA Classic™ requires the insertion of index finger into the oral cavity. Several anesthesiologists are reluctant to do this. We conducted this study to evaluate the modified technique of insertion of LMA Classic™ (not requiring insertion of fingers into the patient's mouth) against the standard index finger insertion technique.Materials and Methods:This prospective, randomized, comparative study was conducted on 200 consenting patients. Patients suitable for anesthetic with LMA Classic™ were randomized to standard technique group (standard insertion technique) and modified technique group (technique not requiring digital intraoral manipulation). Laryngeal mask airway (LMA) was inserted by five designated anesthesiologists. Anesthetic protocol was standardized. Time taken to achieve an effective airway, ease of insertion, glottic view obtained through LMA, and incidence of sore throat were assessed.Results:Patient characteristics and duration of surgery were comparable between the groups. Time to achieve an effective airway was comparable [18.5 (8) s with standard technique and 19.7 (10) s with modified technique; data are mean (standard deviation)]. Ease of insertion (92 easy with standard technique and 91 easy with modified technique), success rate (99% in both the groups), glottic view with fiberoptic bronchoscope, and sore throat incidence (six patients with standard technique and eight patients with modified technique) were comparable. The first attempt success rate was significantly higher with the standard technique (98 patients in the standard technique group and 91 patients in the modified technique group).Conclusions:LMA Classic™ can be inserted successfully without the need to insert index finger into patient's mouth, though the first attempt success rate is higher with the standard technique.

Morphology and function of the hyoid apparatus of fossil xenarthrans (mammalia)

The analysis of the hyoid apparatus of fossil xenarthrans provides insight on the form of the tongue and its function in food intake and intraoral processing. The hyoid apparatus of xenarthrans is notable for fusion among its elements. The presence of a V-bone, a complex consisting of fused basihyal and thyrohyal bones, is a consistent and probably synapomorphic feature of xenarthrans. Fusion of other elements is variable in fossil xenarthrans. Most fossil sloths retain independent elements, as in living dasypodids and mammals generally. Among nothrotheriids, the elements are slender and their articular surfaces indicate considerable mobility, and the relatively long and horizontal orientation of the geniohyoid muscle suggests considerable tongue protrusion. Among mylodontines, such as Paramylodon and Glossotherium, the elements indicate relatively mobile articulations, except between the stylo- and epihyals. The relatively posterior placement of the apparatus and the length and alignment of the geniohyoid muscle indicate considerable capacity for tongue protrusion. Scelidotherium, however, had rigidly articulated stylohyal and epihyal, and the apparatus lies farther anteriorly, which together with the elongated, steeply inclined mandibular symphysis, indicates a relatively shorter geniohyoid muscle and thus more limited capacity for tongue protrusion. A similar situation is indicated for Megatherium, casting doubt on the classical reconstruction of this sloth as having a long prehensile tongue. Among cingulates Prozaedyus resembles living dasypodids, indicating considerable tongue protrusion important in food acquisition and intake. More extensive fusion of hyoid elements occurs in the cingulates Glyptodon and Proeutatus, in which the stylohyal and epihyal at least, are fused into a single element termed the sigmohyal. The presence of this element supports recent proposals of a sister-group relationship between glyptodonts and eutatines. The rigidity of the apparatus suggests limited tongue protrusion, but the tongue, in glyptodonts at least, was a powerful structure important for intraoral manipulation of food.

Face Primary Somatosensory Cortex Motor Representations: Effects of Intraoral Manipulation

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Contribution of the Cheeks to the Intraoral Manipulation of Food

The role of the teeth in chewing has been studied extensively; however, less attention has been paid to soft tissue function. In this study the process of mixing within the bolus and the contribution of the cheeks to this process were investigated using a test food constructed from two differently colored chewing gums. A cheek guard was placed into either the left the or right buccal sulcus. Eighteen dentate subjects were instructed to chew four samples of gum for 30 strokes, two samples with the cheek guard in place and two without. Upon completion, the gum was removed from the mouth and its length was measured. The bolus was then placed into a plastic bag and flattened. Pairs of flattened samples chewed with and without the cheek guard in place were then assessed by five judges who were asked to identify which of each pair was most mixed. Inhibition of the cheek during chewing resulted in significantly longer samples, which were also less mixed.

Tube obstruction of CobraPLA in a patient with fixed flexed neck

oxygenation and ventilation of the patient became insufficient. Subsequently, we attempted to insert an LMA-ProSeal with digital intraoral manipulation to manage the airway. However, the insertion was unsuccessful, possibly due to the patient’s short interdental distance of 2.5 cm. We then inserted the CobraPLA, which enabled us to provide successful oxygenation. Thereafter, however, we found inspiratory resistance. The X-ray revealed that the CobraPLA was flexed in the midpharynx (Fig. 1). The tube was flexed and obstructed because the patient’s neck was fixed in flexion, which limited further movement (2‐3 cm) in addition to the mouth opening limitation (Her thyromental distance was 4 cm). Finally, we were able to ventilate the patient using slow inspiratory flow after a minor correction of the tube position. When a certain portion of the CobraPLA, which is made of vinyl chloride, is flexed, it can easily collapse in the fulcrum. The obstruction of the tube can be avoided if the CobraPLA has a spiral structure to provide flexibility, which is similar to that of a spiral tube or LMA-ProSeal. This obstruction of the CobraPLA should be taken into account when it is used for a patient whose neck is fixed in flexion, such as in the condition of rheumatoid arthritis.

Oral processing assessed by M-mode ultrasound imaging varies with food attribute

Ultrasonic imaging was used to quantify oral movements made during the oral processing of foods while subjects assessed the intensity of the sensory attributes, thick, creamy, sweet and bitter. A series of four stimuli were prepared with high and low viscosities and high and low sweetness. Over five sessions, subjects (N=8) were asked to consume 5 ml spoonfuls of each of the stimuli while holding an ultrasound probe beneath their chin so as to produce a mid-line sagital image of the floor of the mouth and tongue. In the first session, subjects were asked to swallow the sample. In subsequent sessions, subjects were asked to rate one of the attributes, thickness, sweetness, creaminess or bitterness, in random order. The resulting video recordings were subjected to an image-processing algorithm to quantify the amount of intra-oral manipulation performed. The results demonstrated that oral movements varied with attribute, especially in the period during which the bulk of the food is typically processed and the following swallowing phase. The food's sweetness affected oral movements especially during the bulk phase, whereas the food's viscosity primarily affected movements during the following swallowing and clearance phases.

Impaired mastication modifies the dynamics of bolus formation

Mastication is a complex sensory-motor activity whereby a food product is transformed into a bolus. Consumers mainly perceive the sensory properties of the food during the intra-oral manipulation of the product. Consequently, the quality of the chewing process could have consequences on the perception of sensory properties and food choice. By focusing on meat products, this study aimed to analyze the influence of dental status on (i) dynamic adaptation of the chewing behavior (evaluated by electromyography) to the changes in texture during bolus formation and (ii) bolus properties (mechanical resistance and saliva incorporation) obtained from meat of different initial textures. Two groups of subjects (dentate subjects and denture wearers), known to present highly different chewing efficiency, were compared. For both groups, salivary flow rates were evaluated at rest and after stimulation by chewing (paraffin and meat). The salivary flow rates, assessed during chewing of a nonedible matrix (paraffin), were a good predictor of salivary flow rates induced by meat chewing for both groups of subjects. Salivary flow rates were not affected by the dental status. In contrast, the chewing behavior varied between groups. For denture wearers, the chewing pattern was strongly impaired and not adapted to the changes in meat structure during bolus formation. Denture wearers swallowed less fragmented boli than dentate subjects, but boli had a similar level of moisture for both groups of subjects.

In vitro simulation of the oral processing of semi-solid foods

The intra-oral processing of semi-solids foods is dominated by effects due to tongue movement. These movements subject the food to shear forces and mix it with saliva. Both actions tend to reduce the viscosity of the products. These changes are perceived as “melting” by sensory panellists. In a previous study where subjects were trained to use a variety of intra-oral manipulation it was shown that the amount of tongue movement was an important factor in determining the sensory experience of the products. The goal of this study was to develop a system which could measure changes in viscosity due to temperature, shear, dilution and structure breakdown, monitor the rate of and extent of mixing, mimic the pattern of mixing extant in the mouth. Simulation requires that shear forces, mixing and thermal effects be mimicked faithfully. To compare samples recovered from the mouth with those mixed in the simulator we compare the amount of mixing as measured using an image-processing technique. The simulator allows the effects of shear, dilution, and α-amylase concentration on the rheology and heterogeneity of the product to be monitored in real time. By way of example the effects of dilution, shear and chemical breakdown are compared in a starch-based semi-solid food.

A case series of closed reduction for acute temporomandibular joint dislocation by a new approach

The management of acute temporomandibular joint dislocation relies on the traditional method, which involves intraoral manipulation of the mandible on both sides of the patient. Often, intravenous sedative or analgesic agents are needed to facilitate closed reduction. In this report, the authors introduce a new approach called the ipsilateral approach, in which extraoral or intraoral manipulation of the dislocated side is performed to accomplish closed reduction, without using sedatives or analgesics. Three methods, namely, extraoral, intraoral and combined, are described. A prospective observational study was performed to investigate this ipsilateral approach. Six medical officers were recruited to attend to patients with acute temporomandibular joint dislocation. The following protocol was used: (1) Try the extraoral method in all patients first. (2) If it fails, use the intraoral method. (3) If both fail, attempt using a combined method. (4) If all fail, perform the traditional method as usual. A total of 24 episodes of temporomandibular joint dislocation were examined, out of which 13 were successfully reduced by the extraoral method. Of the remaining 11 episodes, 10 were successfully reduced by the intraoral method, the last case being reduced by the combined method. None of them requires sedation or analgesia. This ipsilateral approach, using extraoral and intraoral methods, is cost-effective, simple and convenient for the management of acute temporomandibular joint dislocation.

Sensory and motor function of teeth and dental implants: A basis for osseoperception

1. When dental implants are loaded mechanically, a sensation, often referred to as osseoperception, is evoked. The sensory signals underlying this phenomenon are qualitatively different from the signals evoked when loading a natural tooth. In contrast with osseointegrated dental implants, natural teeth are equipped with periodontal mechanoreceptors that signal information about tooth loads. In the present review, the functional properties of human periodontal mechanoreceptors will be presented, along with a discussion about their likely functional role in the control of human jaw actions. 2. Microneurographic experiments reveal that human periodontal mechanoreceptors adapt slowly to maintained tooth loads. Populations of periodontal receptors encode information about both which teeth are loaded and the direction of forces applied to individual teeth. 3. Most receptors exhibit a markedly curved relationship between discharge rate and force amplitude, featuring the highest sensitivity to changes in tooth load at surprisingly low forces (below 1 N for anterior teeth and 4 N for posterior teeth). Accordingly, periodontal receptors efficiently encode tooth load when subjects first contact, hold and gently manipulate food by the teeth. In contrast, only a minority of receptors encodes the rapid and strong increase in force generated when biting through food. 4. It is concluded that humans use periodontal afferent signals to control jaw actions associated with intra-oral manipulation of food rather than exertion of jaw power actions. Consequently, patients who lack information from periodontal receptors show an impaired fine motor control of the mandible.