• Restorative Dentistry and Endodontics
• /
• v.24 no.4
• /
• pp.657-665
• /
• 1999

The effects of application of mustard oil (MO), a small-fiber excitant and inflammatory irritant into the rat maxillary molar tooth pulp on arterial blood pressure and heat race, and electromyographic (EMG) activity of the jaw muscles were assessed in the anesthetized rats. In addition, Evans blue extravasation following pulpal MO application was measured. Application of MO into the tooth pulp produced a significant increase in mean arterial pressure and heat rate which gradually returned to baseline level. Application of MO into the tooth pulp induced a significant and short-lasting increase in EMG activity of digastric masseter and tongue muscle. Application of MO into the tooth pulp significantly increased the plasma extravasation of Evans blue dye. However, Application of mineral oil into the tooth pulp did not produce any significant changes in EMG activity of the digastric, masseter and tongue muscles, mean arterial pressure and heart rate, and plasma extravasation of Evans blue dye. These findings indicate that changes in arterial blood pressure, heart rate, jaw muscle activity and plasma extravasation accompanying noxious tooth pulp stimulation call be utilized as indirect measure of orofacial pain and inflammation.

• Journal of Dental Anesthesia and Pain Medicine
• /
• v.21 no.2
• /
• pp.173-178
• /
• 2021

Inferior alveolar nerve (IAN) injury is usually caused by stretching or crushing of the neurovascular structures and postoperative intra-alveolar hematoma or edema after dental procedures. This results in paresthesia in the ipsilateral chin, lip (vermilion border, skin, and mucosa), and labial or buccal alveolar mucosa of the mandibular anterior teeth. However, there are no reports of sensory alterations in the teeth, especially tooth hypersensitivity, after IAN injury. I report a case in which paresthesia of the lower lip and hypersensitivity of the lower anterior teeth occurred simultaneously after the removal of the third molar that was located close to the IAN. In addition, I discuss the reasons for the different sensory changes between the tooth and chin (skin) after nerve injury from a neurophysiological point of view. Since the dental pulp and periodontal apparatus are highly innervated by the inferior alveolar sensory neurons, it seems necessary to pay attention to the changes in tooth sensitivity if IAN injury occurs during dental procedures.

• The korean journal of orthodontics
• /
• v.43 no.5
• /
• pp.218-224
• /
• 2013

Objective: To examine the effect of bite force on the displacement and stress distribution of orthodontic mini-implants (OMIs) in the molar region according to placement site, insertion angle, and loading direction. Methods: Five finite element models were created using micro-computed tomography (microCT) images of the maxilla and mandible. OMIs were placed at one maxillary and two mandibular positions: between the maxillary second premolar and first molar, between the mandibular second premolar and first molar, and between the mandibular first and second molars. The OMIs were inserted at angles of $45^{\circ}$ and $90^{\circ}$ to the buccal surface of the cortical bone. A bite force of 25 kg was applied to the 10 occlusal contact points of the second premolar, first molar, and second molar. The loading directions were $0^{\circ}$, $5^{\circ}$, and $10^{\circ}$ to the long axis of the tooth. Results: With regard to placement site, the displacement and stress were greatest for the OMI placed between the mandibular first molar and second molar, and smallest for the OMI placed between the maxillary second premolar and first molar. In the mandibular molar region, the angled OMI showed slightly less displacement than the OMI placed at $90^{\circ}$. The maximum Von Mises stress increased with the inclination of the loading direction. Conclusions: These results suggest that placement of OMIs between the second premolar and first molar at $45^{\circ}$ to the cortical bone reduces the effect of bite force on OMIs.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.40 no.4
• /
• pp.314-320
• /
• 2013

With a prevalence rate of 0.01%, the presence of eruption disturbances of mandibular first molar has rarely been in populations. Eruption disturbances of permanent molars have been usually manifested as impaction, primary retention, and secondary retention. The treatments of eruption disturbances are carried out by: periodic observation; surgical exposure; forced eruption after surgical exposure; forced eruption with luxation; surgical repositioning; and extraction. This case report show successfully erupted mandibular first molars by various treatment methods on five patients diagnosed with impaction, primary retention, and secondary retention, respectively. Eruption disturbances of the mandibular first molar can be properly diagnosed with impaction, primary retention, and secondary retention by clinical and radiographic examination at normal eruption time of the mandibular first molar. The treatment should be done synthetically, considering eruption state of affected tooth, the relationship between the affected tooth and the adjacent or opposite tooth, the patient's age, treatment compliance, and economic state.

• The korean journal of orthodontics
• /
• v.41 no.3
• /
• pp.191-199
• /
• 2011

Objective: The purpose of this study was to investigate the stress distribution on the orthodontic mini-implant (OMI) surface and periodontal ligament of the maxillary first and second molars as well as the tooth displacement according to the OMI position in the dragon helix appliance during scissors-bite correction. Methods: OMIs were placed at two maxillary positions, between the first and the second premolars (group 1) and between the second premolar and the first molar (group 2). The stress distribution area (SDA) was analyzed by three-dimensional finite element analysis. Results: The maximal SDA of the OMI did not differ between the groups. It was located at the cervical area and palatal root apex of the maxillary first molar in groups 1 and 2, respectively, indicating less tipping in group 2. The minimal SDA was located at the root and furcation area of the maxillary second molar in groups 1 and 2, respectively, indicating greater palatal crown displacement in group 2. Conclusions: Placement of the OMI between the maxillary second premolar and the maxillary first molar to serve as an indirect anchor in the dragon helix appliance minimizes anchorage loss while maximizing the effect on scissors-bite correction.

• The korean journal of orthodontics
• /
• v.48 no.5
• /
• pp.339-345
• /
• 2018

Objective: The purpose of this study was to clarify the effects of continuous force application for extrusive tipping movement and occlusal interference on periapical root resorption in the rat mandibular first molar. Methods: We constructed an appliance comprising a titanium screw implant with a cobalt-chromium post as the anchorage unit and a nickel-titanium closed coil spring (50 cN) as the active unit. Force was applied on the mandibular left first molar of rats for 8 (n = 10) and 15 days (n = 10; experimental groups), with the tooth in occlusion. Five rats were included as a non-treated control group to examine the body effect of the appliance. Active root resorption lacunae, identified using tartrate-resistant acid phosphatase, were evaluated in terms of the length, depth, and area. Results: The rat mandibular first molars were mesially tipped and extruded in the occlusal direction. This mesio-occlusal tipping movement and occlusion resulted in the formation of a compression zone and active root resorption lacunae in the distoapical third of the distal roots. However, there was no significant difference in the amount of root resorption between the two experimental groups. The control group did not exhibit any active root resorption lacunae. Conclusions: Periapical root resorption was induced by continuous extrusive tipping force and occlusal interference in rat mandibular molars. These data suggest that we orthodontists had better take care not to induce occlusal interference during our orthodontic treatment.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.36 no.1
• /
• pp.57-61
• /
• 2010

In the presence of acute pericoronitis of mandilbular third molar, antibiotic therapy and early incision and drainage are the method of choice, followed by definitive surgical extraction of the tooth as soon as it becomes subacute. If excision of the overlying tissues is decided on, it should be done adequately. All overlying tissues must be throughly excised, and the crown portion of the unerupted tooth should be completely exposed. After excision has been completed, the wound should be managed with a surgical dressing. This should be allowed to remain approximately 7 days. And then, surgical extraction of the impacted mandibular third molar can be done usually. In this operation, there are many complications, such as, postoperative bleeding, infection, trismus, dysphasia and paresthesia. The surgeon are discredited and medicolegal problem may be occurred in the presence of many distressed complications. Therefore, the relatively nonsurgical treatment is the method of choice. So, authors selected the conservative treatment methods of incision and drainage, primary endodontic drainage, operculectomy without surgical extraction of the mandibular third molars. The results were more favorable without the postoperative complication in Wonju old offender prison.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.42 no.3
• /
• pp.257-263
• /
• 2015

Impacted teeth occur at higher frequencies in permanent than primary dentition. The most frequently affected teeth are the maxillary and mandibular third molars, whereas it is quite uncommon for the mandibular first molar to be impacted. Treatment methods for impacted teeth include continuous examination for independent eruption, surgical exposure, subluxation after surgical exposure, orthodontic traction, and surgical repositioning. If all of these treatments fail, tooth extraction may be considered. In the first case study, an 8-year-old boy was treated with surgical exposure, after which he was fitted with an obturator. His mandibular first molar then erupted successfully. In the second case, we treated a 12 year-old boy using orthodontic traction. This study describes children with tooth eruption disorders of the mandibular first molar in mixed dentition, and reports acceptable results regarding treatment of the impacted teeth.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.37 no.1
• /
• pp.136-142
• /
• 2010

Ectopic eruption is defined as the eruption of the tooth in an abnormal position or orientation. In the molar region, ectopic eruption may cause distal root resorption and premature exfoliation of the neighbor teeth and uncontrolled space loss is followed. Prolonged partial impaction of the permanent molar may also cause undetected caries or abscess formation of the neighbor teeth. While 66% of ectopically erupting permanent molars are corrected spontaneously without treatment, the treatment is necessary for the irreversible ectopic eruption cases. The optimal treatment approach depends on a number of factors including the clinical eruption status of the molar, amount of enamel ledge and the mobility of the neighbor tooth, and the presence of pain or infection. This case report presents the results of treatment of the ectopically erupting maxillary first permanent molars and mandibular second molars using elastic separators or modified Halterman appliance with or without surgical approach.

• The korean journal of orthodontics
• /
• v.49 no.6
• /
• pp.349-359
• /
• 2019

Objective: The aim of this study was to analyze three-dimensional (3D) changes in maxillary dentition in Class II malocclusion treatment using arch wire with continuous tip-back bends or compensating curve, together with intermaxillary elastics by superimposing 3D virtual models. Methods: The subjects were 20 patients (2 men and 18 women; mean age 20 years 7 months ${\pm}$ 3 years 9 months) with Class II malocclusion treated using $0.016{\times}0.022-inch$ multiloop edgewise arch wire with continuous tip-back bends or titanium molybdenum alloy ideal arch wire with compensating curve, together with intermaxillary elastics. Linear and angular measurements were performed to investigate maxillary teeth displacement by superimposing pre- and post-treatment 3D virtual models using Rapidform 2006 and analyzing the results using paired t-tests. Results: There were posterior displacement of maxillary teeth (p < 0.01) with distal crown tipping of canine, second premolar and first molar (p < 0.05), expansion of maxillary arch (p < 0.05) with buccoversion of second premolar and first molar (p < 0.01), and distal-in rotation of first molar (p < 0.01). Reduced angular difference between anterior and posterior occlusal planes (p < 0.001), with extrusion of anterior teeth (p < 0.05) and intrusion of second premolar and first molar (p < 0.001) was observed. Conclusions: Class II treatment using an arch wire with continuous tip-back bends or a compensating curve, together with intermaxillary elastics, could retract and expand maxillary dentition, and reduce occlusal curvature. These results will help clinicians in understanding the mechanism of this Class II treatment.