Lower Left Molar Research Articles

Rescue of a “hopeless” second premolar

We present a case of a young male who was referred to our clinic because of a deep caries on the first lower left molar. The patient refused conservative treatment, and the caries progressed. After 2 years the first lower left molar had to be extracted. During standard x-ray procedures, a deeply impacted second lower left premolar was diagnosed. The boy was followed by our staff, and surgery was performed at proper time to enable eruption of the second lower left premolar. Orthodontic treatment allowed us to bring the element in a suitable position to place a provisional Maryland bridge. At a later stage the missing element (first lower left molar) will be replaced by an osteointegrated implant.

Synaptic contacts established by primary sensory fibers innervating the teeth of rats: An ultrastructural study of the pars interpolaris of the spinal trigeminal nucleus

Transganglionic degeneration was used in an electron microscopic study of afferent synaptic contacts in the dorsomedial region of the pars interpolaris of rats. In one experiment, the left inferior alveolar nerve was transected and in the other, partial pulpectomy of the first and second left lower molars was performed. Well defined degenerating terminals, almost completely occupied by round synaptic vesicle profiles were found in both ipsi and contralateral sides. In both experiments, approximately 70% of these terminals formed single asymmetric contacts with intermediate or distal dendritic segments. Fewer contacts were observed with proximal dendritic segments, dendritic spines, perikarya and other terminals. In addition, double and multiple synaptic contacts (synaptic glomeruli), accounting for 10% of the total, were also observed. Quantitative data regarding ultrastructural synaptic elements suggest that there is no preference for post-synaptic sites of fibers related to different sensory modalities such as pain, conveyed by dental fibers or other modalities, conveyed by the interior alveolar nerve fibers.

Pressure from the tongue on the teeth in young adults.

Pressure from the tongue on the teeth was measured at the upper and lower central incisors and left first molars in 25 young adults with clinically normal occlusion. Repeated recordings with and without a period for accommodation to the intraoral measuring device, which was connected to an extraoral pressure transducer, were made in the rest position and during chewing and swallowing. Only minimal effects of accommodation were found. The system can thus be used without a period of adaptation before the actual test. The intraindividual pressure variations were of the same magnitude as for measurements of the pressure from the oro-facial soft tissues on the teeth recorded in earlier studies. The majority of the subjects had negative pressures at the upper and lower incisors and at the upper molar in the rest position. The pressures on the teeth during swallowing were comparatively great, while pressures during chewing were one-fourth to one-half of the swallowing pressures.

下顎骨に発生した動静脈ろうの１例

A case of arteriovenous fistula of the mandible was reported. A 54 year old man visited our hospital and complained of mobility of left lower molar. On the first visit he had a diffuse swelling at the left mandibular gingiva but gingiva showed healthy color.Orthopantomography showed extending radiolucent lesion from 1 to 6, and it was suspected to be cyst or some benign tumor. We carried out biopsy at P gingiva and then severe hemorrhage occurred. Tamponade and some hemostatic techniques were not effective. Emergency operaion of ligation of external carotid artery was carried out under local anestheisa, so hemorrhage stopped. Clinical diagnosis was hemangioma in mandible.At 4 weeks after operation, gingiva was swelling again, and partial resection of the mandible was performed and reconstructed with A-0 reconstruction plate. The postoperative course was entirely good and without recurrence.The pathological diagnosis was arteriovenous fistula.

Interaction of phenytoin and inflammation induces gingival overgrowth in rats.

In adult male Wistar rats (Rattus norvegicus albinus) gingival irritation provided by means of wire silk ligatures around the cervix of first left lower molars, for a duration of 77 days, caused gingival inflammatory changes. In the rats receiving also daily one i.p. injection of sodium 5,5‐diphenythydantoinate (phenytoin), during 70 days, there was no macroscopical change of the gingiva of non‐ligated first right lower molars. However, in the first left lower molars, the association of silk ligature‐plus‐phenytoin administration elicited gingival overgrowth. The rat was seen as a satisfactory animal model for studies of phenytoin‐induced gingival changes.

機能下にある歯がの水平面内における変位に関する研究

The objective of this work is to investigate the horizontal tooth displacement and the behavior of the interdental proximal contact relation in function. As the transducer, two Magnesensors®were used. The movement of the upper and lower left molars were measured. Based on the results of these experiments, the following conclusions can be made:1. The upper molars showed the displacement ranging from 10to 146μm in the disto-lingual direction during biting.2. The lower molars showed the displacement ranging from 16to 109 μm in the mesio-lingual or the lingual direction during biting.3. The displacement of the lower molars in the mesiodistal direction was less than that of the upper molars. 4. The upper molars showed the displacement ranging from 91to 196 μm in the disto-lingual direction during mastication.5. In the lingual or the disto-lingual direction, the lower molars showed the displacement ranging from 29 to 55 μm and 56to 73 μm in the buccal or the mesiobuccal direction during mastication.6. The tooth which has the loose contact showed wider displacement path in the mesio-distal direction during mastication.7. The dental arch width decreased in function.

Miocene tree shrews from the Indian Śivaliks

There have been no definite reports of fossil tree shrews although a rib cage from the Tatrot Formation of India has been identified as Tupaia1, and fossil material, including the anterior part of a skull (YGSP 8089) with broken crowns of teeth (I1–P4) and a lower left molar (YGSP 8090), from the Middle Śivaliks of Pakistan, has been assigned to the sub-family Tupaiinae (unpublished results by I. Jacobs). The lack of material makes it difficult to assess the evolutionary position of this group, which, together with moles and hedgehogs, is considered to include the most direct modern descendents of the primitive placentals2. The living tree shrews have also attracted great interest because of the suggestion that they are related to primates. We report here a maxillary fragment (PUA I5) of the left side with M1–M3 and an isolated right lower molar, probably M2, (PUA I6) recovered from the middle Śivalik deposits of Haritalyangar in Himachal Pradesh, India. We have referred this to the Tupaiinae, although we cannot assign generic and specific names. The following communication3 describes more substantial material discovered later.

Fossil Camels in Kenya and Tanzania

Two large fossil teeth similar to those of ruminants* but clearly neither bovid nor giraffid have been found in the collections of the Centre for Prehistory and Palaeontology, Nairobi. One is a damaged right upper molar (1955.257) from site BK near the top of bed II at Olduvai Gorge, and the other a left lower molar from the Marsabit Road site in northern Kenya at 2° 30′ N, 37° 27′ E. They have been identified as camelid, and thus extend the former range of this family still farther south from Omo.

Necrosis of cementum induced by root canal treatments in the molar teeth of rats

In order to study the causes and evolution of cementum necrosis, root canal treatment was carried out in the mesial root of the first left lower molar in 154 white rats. Animals were sacrificed from 3 to 90 days after treatment. Histological studies allowed the following conclusions to be drawn: 1. 1. Cementum necrosis due to the chemical irritation provoked by the filling material employed, and to the toxic bacterial action of detritus caused by instrumentation, was seen extending outwards from the cementodentinal junction. Necrosis became more severe as dentine thickness decreased. 2. 2. In specimens showing infarct necrosis of the periodontal ligament, or periapical abscess, necrosis of the cementum started from the periodontal surface and spread towards the cementodentinal junction. 3. 3. Resorption of the necrotic cementum was frequently observed, causing, in some instances, total removal of cementum and dentine in the apical zone. 4. 4. When the cause provoking the necrosis was not persistent and the periodontal ligament was normal, apposition of new cementum over necrotic cementum was seen occasionally.

Szczątki żubra, Bison bonasus (L.), z Podhala

The author describes Romains of a European bison, viz.: the left horn-core with some adjoining bones found in the village Szaflary in a mound of a castle built in the XIII century, and third left lower molar from the village Łopuszna. This horn-core seems to be that of a bull. Its circumference at the base is almost of the same size as those of the bison living at Bialowieza at present, but its length is greater.These remains of historical date were found in the Nowy Targ valley situated about 650 m a. s. l., while other remains of the European bison known up till now from Poland were found all in much lower regions.

CERVICOFACIAL ACTINOMYCOSIS SUCCESSFULLY TREATED BY PENICILLIN WITHOUT SURGICAL DRAINAGE

Two cases of proved cervicofacial actinomycosis treated successfully by penicillin without the employment of surgical drainage are herewith presented. Case 1. —A housewife aged 27, admitted to the University Hospital July 28, 1944, had begun six weeks previously to have toothache, limitation of motion of the jaw and swelling in the region of the left lower molars. A week later spontaneous drainage into the mouth of what was apparently an alveolar abscess occurred, with subsequent temporary slight diminution in the swelling. Roentgenograms on July 17 showed caries of the crowns of the second and third left lower molars and an abscess around the root of the third. Two days later these teeth were extracted. Hot compresses were used, but there was no improvement in either the size of the mass or the motion of the mandible. On admission the temperature was 37.5 C. (99.6 F.). Over the angle

Department of Radiodontia

HomeRadiologyVol. 3, No. 2 PreviousNext ArticlesDepartment of RadiodontiaUnder the Supervision of Boyd S. Gardner, D.D.S., Rochester, MinnesotaPublished Online:Aug 1 1924https://doi.org/10.1148/3.2.164MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In AbstractCase ReportDr. M. R. Howard, of Denver, Colorado, reports the following case, illustrated with full-mouth roentgenograms:The patient, a boy aged 10 years, weighing 100 pounds, first revealed signs of physical disturbance by failing in his school work; later his mind became so affected that it was necessary to leave school. Epileptic attacks followed, as many as three each day. He sometimes was vicious with his mother and his friends, and was afraid to leave his father even in the daytime. After one year and a half, the mouth was examined and clinically appeared to be in good condition. However, a full-mouth roentgenogram disclosed three mandibular supernumerary teeth entirely within the bone, two on one side and one on the other (Fig. 1). There was no bulging of tissue in the mouth to indicate the condition. Two impacted lower third molars and two un-erupted upper third molars were also found. The lower left molar was the only pulpless tooth. All of these questionable teeth were removed, and since the last extraction epileptic attacks have ceased and the boy has improved steadily, and has resumed his school work. The patient is now 20 years old, has taken an active part in athletics for the last two years, has learned the bricklaying trade, and is now working every day. He is strong and healthy and weighs over 155 pounds.Article HistoryPublished in print: Aug 1924 FiguresReferencesRelatedDetailsRecommended Articles RSNA Education Exhibits RSNA Case Collection Vol. 3, No. 2 Metrics Altmetric Score PDF download

On the Animal-remains found by Colonel Lane Fox in the High- and Low-terrace Gravels at Acton and Turnham Green

I. High-terrace Gravel . The animal-remains from the High-terrace Gravel belong to Bos , Ovis , Equus * and Elephas ? 1. Bos .—The bovine remains comprise by far the greater part of the specimens collected at this level. They are all in a comparatively recent condition, though some appear to have more exposed to atmospheric influence previous to interment than others. Most of the bones also exhibit marks of cutting or chopping with a sharp metallic implement; and none have been exposed to fire. Some few present faint indications of manganous deposit, in the form of minute specks; but none, with one exception, can be called dendritic, nor do any of them adhere to the tongue, or but very slightly so. In fact, they may nearly all be regarded as of modern origin, and as belonging to the common ox of rather small size. A perfect metacarpal measures 8 inches in length. Amongst the bovine remains is what appears to be a portion of the metacarpal of a calf. 2. Ovis —The ovine relics are very few in number, and all modern. 3. Equus .—Two specimens only belonging to the horse occur in the High-level collection, viz. a left lower molar and a portion of the right scapula, including the glenoid cavity. Both these specimens are dendritic; and the fragment of the scapula is highly ferruginous and much decomposed, apparently from subaerial exposure, so that the surface scales off in thin laminæ From their condition, these bones would seem to belong to a different period than those