Left Premolar Region Research Articles

Atypical hard tissue formation around multiple teeth

Over the preceding 4 months, a 36-year-old man had noticed an irritation of the gingiva in the upper left premolar and molar region with exposure of root surfaces. He did not complain of pain. Other than a history of smoking (20 cigarettes per day, 20 cumulative packyears), the patient did not present with any medical problems and was not taking any medications. The patient, who was a farmer, reported a trauma which had taken place 15 years earlier, in which a cow horn had perforated his left cheek. No dental trauma had been noted and no radiographs had been taken at that time. On clinical investigation, a flattening of the left cheek and a scar in the overlying skin were visible. No intraoral swelling or expansion was present. On the buccal side of the upper left first molar and in the interdental space next to the second premolar, extensive gingival recession with exposure of a brownish irregular hard dental structure was conspicuous (Fig. 1). The hard structure seemed to be fused to the roots. Periodontal pocket probing in the upper left jaw gave

The relation between bone mineral density in the heel and pixel intensity in the mandibular jaw bone among elderly women

The purpose of this study was to investigate the correlation between pixel intensity (PI) in digital radiographs of the lower jaw and bone mineral density (BMD) in the heels of post-menopausal women (as measured with DXL, a combination of dual energy X-ray absorptiometry and lasers). Two intraoral periapical digital radiographs were taken in the right and left mandible premolar region, and the digital images were analysed by a computer program (Dimaxis) regarding PI. As the radiographs were taken, the BMD of the patient's left heel was measured via a portable Calscan device. The patient answered a questionnaire concerning risk factors. The correlation between variables was analysed using statistical tests. A significant correlation was found between the PI in the left (P = 0.001) and right (P = 0.004) mandible and the BMD of the left heel for the whole group. A pronounced correlation was found to exist for women > 70 years old. Based on a cut-off value of the PI, to differentiate between healthy individuals and those who required further analysis for osteoporosis, the following values were obtained: sensitivity 0.74, specificity 0.50, positive predictive value 0.77 and negative predictive value 0.46. A positive correlation was found between PI in digital radiographs of the mandible and the BMD of the heel. The low predictive value does not allow any definite conclusions to be drawn from the present study. A reasonable recommendation could be for future studies to employ a larger study population to explore the effect on this value.

Floating retained root lesion mimicking apical periodontitis

A case of a retained root tip simulating apical periodontitis on radiographic examination is described. The retained root tip, originating from the left lower first molar, floated under the left lower second premolar apical region mimicking apical periodontitis. It appeared as an ill-defined periapical radiolucency containing a smaller radiodense mass on radiograph. The differential diagnosis included focal sclerosing osteomyelitis (condensing osteitis) and ossifying fibroma. Upon exicisional biopsy, a retained root associated with granulation tissue was found. After 1-year follow-up, the patient was asymptomatic and the periradicular lesion was healing. Meanwhile, the associated tooth showed a normal response to stimulation testing.

下顎骨に生じた腺性歯原性嚢胞の１例

We report a case of glandular odontogenic cyst (GOC) arising in the mandible. The patient was a 55-year-old woman who presented with a painful swelling of the right premolar region of the mandible.Roentgenographic examination revealed a multilocular radiolucent lesion from the right first molar across themidline to the left second premolar region. The clinical diagnosis was a mandibular cyst. Enucleation of the cystand extraction of the teeth were performed with the patient under general anesthesia. Histological examinationshowed a multicystic lesion partially lined by non-keratinized epithelium with focal plaque-like thickening. Thesurface epithelium included eosinophilic cuboidal and ciliated cells. Cyst-like spaces and glandular structureswere also observed within the epithelium. Epithelial islands were also seen in connective tissue of the cyst.Immunohistochemically, epithelial cells were strongly positive for cytokeratin (CK) 13 and 19, but almost negativefor CK18. The histological diagnosis was GOC. The postoperative course was satisfactory, and no recurrencehas been noted 4 years 6 months after the operation.

ビスフォスフォネート製剤によると考えられた上顎骨壊死の１例

Bisphosphonates, nonmetabolized analogues of pyrophosphate, have been widely used to treat patients with hypercalcemia caused by malignancy, bone metastasis, multiple myeloma, and osteoporosis. Recent studies have documented that bisphosphonates can cause osteonecrosis of the jaws. We report a case of bisphosphonateassociated osteonecrosis of the maxilla. A 72-years-old woman was referred to our clinic for further examination of the upper left premolar region. Intraoral examination revealed necrotic alveolar bone in the upper left premolar region, with swelling of the surrounding soft tissue and exposed necrotic bone at the right side of the upper jaw. The patinet had a past medical history of breast cancer with bone metastases to the ribs and received intravenous pamidronate at a dose of 30 mg every 2 weeks. We suspected bisphosphonate-associated osteonecrosis and performed sequestrectomy after antibiotic therapy and local irrigation. Because the number of patients who receive bisphosphonates is increasing in Japan, dentists, especially oral surgeons, should be careful about bisphosphonate-associated osteonecrosis of the jaw bones.

Sporadic ‘true’ gigantiform cementoma

A 54 year old female patient with an asymptomatic mandibular lesion extending from the right tempromandibular joint to the left premolar region. Another lesion involved the right maxilla. The patient claimed that the mass had been present for 10 years. No familial history was noted. The CT scans showed well circumscribed mixed radiolucent-opaque lesions. A diagnosis of multiple ossifying fibromas was made initially. However, it was later revised to sporadic ‘true’ gigantiform cementomas because of multifocal/multiquadrant presentation and the fact the lesions crossed the jaw midline.

Poster 174: Bone Graft on Tooth Missing Area Using the Condyle Fragment of the Condyle Fractured Patient for Prosthetic Treatment Using an Implant: A Case Report

It is quite common to see the maxillofacial fractures accompanying an alveolar bone fracture and tooth luxation. In particular, tooth luxation caused by an alveolar bone fracture can lead to rapid alveolar bone resorption. Therefore, horizontal and vertical alveolar bone augmentation might be required on an area with missing teeth area before implanting an implant. Depending on whether the fractured fragment has been dislocated or not, the direction of the muscle and the condition of the fracture, conservative and/or surgical treatment should be administered for a maxillofacial fracture. In particular, a condyle fracture is very difficult to approach surgically and can accompany TMJ ankylosis, disclusion caused by changes in the vertical dimension, trismus, change in occlusion and bone necrosis. Therefore, treatment should be given under an accurate diagnosis. Condyle fractures accompanying a decrease in the vertical dimension, trismus and an excess dislocation of bone fragments (Class III, V) are efficacious conditions for surgical treatment. The surgical removal of a bone fragment is essential when there is trismus but no changes in the vertical dimension. In order to help treat both a condyle fracture and an area of missing teeth, it is expected that the removed fragment can be used as a graft material on the tooth or alveolar bone lacking site. We describe a 25-year-old male patient who had a left condyle fracture, right subcondyle fracture, right mandible body fracture and left premolar region alveolar bone fracture as a result of an accident. An open reduction of the mandible body fracture, tooth extraction of the alveolar bone fracture site and fragment removal was performed on a patient. Three months after surgery, the bone fragment was removed due to trismus and acute pain caused by the left condyle bone fragment. The removed bone fragment was used as a bone graft on the alveolar bone defect site and the implant was implanted. Jaw opening movement was carried out and a prosthetic treatment was given. The mandibular functions such as masticatory movement and jaw opening movement had recovered some time after surgery.

Acceleration of orthodontic tooth movement by alveolar corticotomy in the dog

Tooth movement and alveolar bone reaction after corticotomies have not been thoroughly examined. In this study, the effects of corticotomies on orthodontic tooth movement and alveolar bone reaction were investigated in dogs. Corticotomies were performed on the cortical bone of the mandibular left third premolar region in 12 male adult beagles. The third premolars on the left experimental side and on the right sham side were moved mesially with a continuous force of 0.5 N. Tooth movement velocities from 0 to 1 week and from 1 to 2 weeks after the corticotomies were significantly faster on the experimental side than on the sham side. Hyalinization of the periodontal ligament appeared only at 1 week after the corticotomies on the experimental sides, whereas it was observed from 1 to 4 weeks after the corticotomies on the sham sides. Tartrate-resistant-acid-phosphatase positive cells of the experimental side tended to work vigorously at an early time on the alveolar wall and in the bone marrow cavities. Orthodontic tooth movement increased for at least 2 weeks after the corticotomies. This might be brought about by rapid alveolar bone reaction in the bone marrow cavities, which leads to less hyalinization of the periodontal ligament on the alveolar wall.

Non-syndrome Multiple Supernumerary Teeth: A Case Report

The purpose of this case report is to present a case of a non-syndrome male patient with multiple supplemental supernumerary teeth in three quadrants of his mouth. Supernumerary teeth are described as the teeth formed in excess of the number found in a normal dentition. Prevalence of supernumerary teeth varies between 0.1% and 3.8% in the general Caucasian population. Multiple supernumerary teeth are not a common occurrence, although a single or a few supernumerary tooth/teeth in each case have been widely reported in the literature. An 11-year-old male presented for a routine preventive dental visit. A routine panoramic radiograph showed the presence of multiple supernumerary teeth which were located in the maxillary right canine incisor region, the maxillary left premolar region, and the mandibular right premolar region. The family's medical history was non-contributory, and an extraoral examination did not reveal any abnormality. It is rare to find multiple supernumerary teeth in individuals with no other associated diseases or syndromes. This case report presents a case of a non-syndrome male patient with multiple supplemental supernumerary teeth in three quadrants of his mouth.

A novel visually CO2 controlled alveolar breath sampling technique

A crucial issue in the analysis of exhaled breath is the collection of gaseous samples. The analysis of pure alveolar gas is the method of choice if contamination of samples is to be minimized. Monitoring of expired CO2 can be used to identify alveolar gas. The purpose of this study was to evaluate a bed side version of this technique using visual CO2 control by means of a capnometer. 22 mechanically ventilated patients of an ICU were enrolled into the study. Alveolar and mixed expiratory gas, and arterial blood were sampled. PCO2 in blood and gas was determined in a blood gas analyzer. End tidal PCO2 was monitored in all patients by a fast responding main stream capnometry. Taking the gaseous samples was visually synchronized with the expired CO2. Alveolar CO2 contents measured during two different respiratory cycles were identical (p 0.86). The variation of the CO2 content during 10 measurements in one patient was lower than 4%. Arterial PCO2, PCO2 in alveolar gas and end tidal PCO2 showed positive correlation. The visually CO2-controlled sampling technique of alveolar gas is a reliable and reproducible method. It represents an important step in simplifying and standardizing breath analysis.

Finite element stress analysis of cuneiform and cylindrical threaded implant geometries

Statement of problem. Different implant geometries present different biomechanical behaviors and in this context, one arising question is how cuneiform implant geometry compares to clinical successful cylindrical threaded implant geometry. Purpose. The purpose of this work was to study stress distribution around cuneiform and cylindrical threaded implant geometries using three-dimensional finite element stress analysis taking the latter as a reference. Material and methods. A model was generated from a computerized tomography of a human edentulous mandible with implants placed in the left first premolar region. The model was supported by the mastication muscles and by temporomandibular joint. A vertical load of 100N was applied at the top of each implant in the direction of their long axes. The mandibular boundary conditions were modeled considering the actual muscle supporting system. Taking muscle forces intensities and directions, balance moment equations were employed to assess the system equilibrium. Cortical and medullary bones were assumed to be homogeneous, isotropic and linearly elastic. Results. The analysis provided results for maximum (S1) and minimum (S2) principal stress and Von Mises (SEQV) stress field. For both geometries, the results showed concentration on one side of the neck, smooth stress distribution along the body and no considerable concentration at the apical area. Conclusion. Results showed similar stress distribution pattern for cuneiform and cylindrical threaded geometries. The stresses profiles along the implants length reproduced their morphology. In both occurred stress concentration at one side of the neck and no body or apical stress concentration.

A Cast Metal Core for a Deformed Implant Body: Case Report

The present report consists of a clinical evaluation of an osseointegrated implant using a cast metal core instead of abutment for a deformed implant body. The intramobile connector insert for the implant in the mandibular left first premolar region broke 7 years after the superstructure was attached to the implant system. The intramobile connector insert was replaced, and the prosthesis was reattached, but the new intramobile connector insert broke again 2 weeks later. A thorough examination confirmed deformation of the upper section of the implant body in the mandibular left first molar region. Breakage of the new intramobile connector insert in the mandibular left first premolar region was believed to be due to deformation of the implant body in the mandibular left first molar region. Therefore, a cast metal core was used to deal with the deformation of the implant body in this region. Although slight bone resorption was observed around the implant body after 5 years, no major problems were found in the implant body itself.

Morphologic comparison of two neutral zone impression techniques: A pilot study

Several studies have compared dentures fabricated using neutral zone and conventional techniques. However, studies comparing swallowing and phonetic techniques for assessing the location and shape of the neutral zone could not be identified in the literature. The purpose of this pilot study was to compare the outline form of the phonetic and swallowing neutral zone impression techniques for the same subjects. Nine denture wearers with advanced mandibular ridge resorption were included in this study. For each subject 2 trays were prepared in autopolymerizing acrylic resin. One method used phonetics and tissue conditioner to shape the neutral zone; the second method used swallowing and modeling plastic impression compound. The resulting neutral zone impressions were leveled to the same occlusal height by gently grinding the occlusal surface on sandpaper until it corresponded with landmarks (corners of the mouth, two thirds of the height of the retromolar pads, bilaterally) noted on the cast. The impression was inverted onto graph paper, and the contour was outlined with a lead pencil. One impression was made for each subject, for each technique. The buccal contours of both neutral zones coincided at the median line. The maximum distance between the zones was measured in a buccolingual direction in the anterior, premolar, and molar regions bilaterally. When the location of the phonetic neutral zone in relation compared to the swallowing neutral zone was buccally oriented, a plus score was given. When the phonetic neutral zone was lingually located, a minus score was given. When the 2 lines coincided, a score of 0 was given. Measurements were made from direct readings on the graph paper. Statistical analysis was performed using the Sign test (alpha=.05). Significant differences were noted buccally in the left molar (P =.031) and right molar (P =.003) regions and also in the left and right premolar regions (P =.007), where the swallowing neutral zone was found to be located buccal to the phonetic neutral zone. Significant differences were also noted lingually, in the right premolar region (P =.015), where the swallowing neutral zone was found to be located lingual to the phonetic neutral zone. There was no significant difference between the techniques for the anterior region. Within the limits of this study, the phonetic neutral zone appears to be narrower posteriorly compared to the swallowing neutral zone, thus limiting premolar and molar positioning.

Spontaneous progression of experimentally induced periimplantitis.

Periimplantitis represents an inflammatory condition that is associated with the presence of a submarginal biofilm and with advanced breakdown of soft and mineralized tissues surrounding endosseous implants. Animal models have been used to describe mechanisms involved in the pathogenesis and treatment of the soft and hard tissue lesions of periimplantitis. The aim of the present experiment was to study the presence and progression of inflammatory lesions in tissues surrounding implants exposed to "experimental periimplantitis". Five Labrador dogs were used. In each dog, 2 or 3 implants were placed in both the left and right edentulous premolar regions of the mandible. Abutment connection was performed 4 months later and a plaque control regimen was initiated and maintained for 5 months. "Experimental periimplantitis" was subsequently induced by ligature placement and plaque accumulation was allowed to progress until about 40% of the height of the supporting bone had been lost. The ligatures were removed, but plaque formation was allowed to continue for an additional 12 months. Radiographs of all implant sites were obtained before and after active "experimental periimplantitis" as well as at the end of the experiment. Biopsies were harvested from the implant sites in 3 of the dogs. The tissue samples were prepared for light microscopy and the sections were used for histometric and morphometric examinations. One implant was lost during the first 2 months of "experimental periimplantitis" and two implants were lost during the 12 months that followed ligature removal. The radiographic examination indicated that varying amounts of additional bone loss occurred in the majority of the implant sites also following ligature removal. The mucosa of all implant sites harbored inflammatory lesions that extended apically of the pocket epithelium. The lesions were separated from the marginal bone by a zone of apparently normal connective tissue. A remission of the destructive inflammatory lesion in the periimplant tissues was seen in some sites following ligature removal, but in the majority of sites additional loss of supporting bone occurred.

Organ radiation dose assessment for conventional spiral tomography: a human cadaver study.

The head of a human cadaver was positioned in a Cranex TOME multifunctional unit (Orion Corporation Soredex, Helsinki, Finland) to measure the organ radiation doses after tomographic examinations of the upper and lower edentulous jaw bone. Five consecutive examinations were carried out in the upper and lower anterior jaw regions to cover the entire frontal area, 2 in the upper and lower left premolar regions, and 3 and 4 in the upper and lower left molar regions, respectively. Each examination consisted of 4 slices with a 2 mm slice thickness. Thermoluminescent dosimeter chips were placed in the thyroid gland and bilaterally in the parotid and submandibular glands. Dosimetric measurements were repeated for the different tomographic examinations mentioned above. For spiral tomography in the maxilla, organ doses for both parotid glands were most elevated, while those for the thyroid glands were the lowest. Average doses per examination reached levels of 0.27 mGy for the right (OS) parotid gland with frontal tomography, and 3.89 mGy and 1.67 mGy for the parotid gland at tube-side (TS) for premolar and molar tomography. For the thyroid gland, a minimal dose of < or = 0.004 mGy was noticed for all examinations. For spiral tomography of the frontal area in the mandible, the OS parotid gland received the highest dose (0.77 mGy), while for an analysis of the premolar and molar areas, doses were more elevated for the TS parotid gland (1.22 mGy and 1.72 mGy, respectively). For the TS submandibular gland, organ doses were also raised, with values of 0.39 mGy for frontal, 1.31 mGy for premolar and 1.61 mGy for molar tomography. This study thus indicates that for conventional spiral tomographic examinations in the maxilla and the mandible, radiation doses for the TS submandibular and parotid glands were significantly more elevated than those to the thyroid gland. These values remain however below the organ doses previously reported for spiral CT involving both a full upper or lower jaw.

Apical nerve transection resulting from implant placement: A 10-year follow-up report

Despite ever increasing sophistication in diagnosis and treatment planning for implant placement, there are occasions where implants are less than ideally placed. The following report demonstrates a situation where the apical aspect of an implant placed in the mandibular left second premolar region resulted in the transection of the apex of the first premolar. This clinical report reviews a 10-year experience of clinical and radiographic follow-up of this event.

Effects of cyclosporine A on plasma cells in experimental gingivitis in dogs

The aim of the present investigation was to evaluate the effect of Cyclosporine A (CsA) on the inflammatory lesion formed in the gingival tissues during de novo plaque formation. 5 beagle dogs were used. On day 0, all teeth of the 5 dogs were scaled and polished. A 6-week period of plaque control including daily tooth cleaning with toothbrush and dentifrice was initiated. A clinical examination regarding plaque and gingivitis was performed, and the plaque control measures were abandoned on the right side of mandible. 3 weeks later, the clinical examination was repeated, samples of subgingival plaque harvested and biopsies obtained from the 3rd and 4th right mandibular premolar regions. The tooth cleaning measures on the left side of the mandible were terminated at this interval. During the following 3 weeks, the animals formed plaque in the lower left premolar regions, and received, 1 x daily, a subcutaneous injection of CsA. At the end of this 2nd plaque formation period (test), the clinical examination was repeated, subgingival plaque was sampled and biopsies from the 3rd and 4th left mandibular premolar regions harvested. The biopsies were prepared for histometric and morphometric analyses. The clinical and histological examinations demonstrated that plaque formation resulted in a gingival lesion (ICT) which, in the 2 periods, had similar size and apical extension. The ICT formed during the CsA administration period, however, harbored an increased number of plasma cells and a reduced macrophage density than the control lesion. It is suggested that CsA administration may result in a Th-2 (T-helper 2-cell) dependent activation of B-lymphocytes.

Mechanical simulation of the human mandible with and without an endosseous implant

Clinical research has demonstrated that a high remodelling rate for cortical bone exists around a rigid endosseous implant. This phenomenon may be regulated by change in the mechanical environment. 3D finite element models of the human mandible with and without an endosseous implant have been created to investigate the mechanical environment adjacent to the left retromolar area where the ipsilateral implant was located. A bite force of 100 N was applied in the left premolar region. The mechanical environment before and after implantation were computed. The environment was characterized by the following parameters: the principal stresses, dilatational stress, and von Mises stress. The changes in these parameters due to the implantation were calculated. The results showed that the mechanical environment adjacent to the implant changed drastically due to the implant. The major changes in the mechanical parameters occurred adjacent to the bone—implant interface at the bony surface. The changes of the distribution of the mechanical parameters due to implantation were different. Implantation effects were local, and did not alter the overall mechanical environment.

下顎骨に発生した骨肉腫の２例

Osteosarcoma of jaws does not always have characteristic clinical symptoms or X-ray findings. Moreover, the disease is sometimes difficult to diagnose histopathologically even based on biopsy specimens. Here, two cases of osteosarcoma of the mandible, which were difficult to diagnose definitely, are reported.Case: A 38-year-old female complained of paresthesia of the mental region. Osteomyelitis was suspected on clinical examination. A biopsy was performed, but a definitive diagnosis could not be established. Subsequently, the swelling increased and the radiological examination showed a ‘sun-ray’ appearance. On histopathological re-examination, a diagnosis of osteosarcoma was established.Case 2: A 38-year old male complained of paresthesia of the left lower lip and swelling of the buccal gingiva of the left lower premolar region. A biopsy was performed under a clinical diagnosis of a malignant tumor of the mandible. However, the histological diagnosis was an aneurysmal bone cyst. After total enucleation, a diagnosis of osteosarcoma was histopathologically established.

Ｐｙｃｎｏｄｙｓｏｓｔｏｓｉｓ患者に併発した慢性上下顎骨骨髄炎の治療経験

We experienced a case of pycnodysostosis in 55-year-old woman complicated with chronic osteomyelitis in the both maxillae. Pycnodysostosis is a genetic disorder of bone characterized by osteosclerosis. In the jaws of our patient hone sclerosis was found around the remaining teeth rachographycally. We thought this increased bone density resulted from combination of the essential sclerosis with the infectious irritation.Exposure of the sequester and pus discharge were also seen at the left second premolar region of the mandible and the left first premolar region of the maxilla.Although a protracted course was encountered for the sclerosing osteomyelitis, the patient was successfully treated by antibiotic therapy and removal of sequester and pathologic bone showing abnormal sclerosis without wide resection of bone such as decortication or saucerization.We discussed the treatment of the chronic sclerosing osteomyelitis including the osteomyelitis in the patient of pycnodysostosis.