Left Lateral Tooth Research Articles

Neonatal line on fetus and infant teeth: An indicator of live birth and mode of delivery

BackgroundThe neonatal line (NL) is an important issue in forensic odontology. It is the sign of a developmental birth defect, which is caused by the effect of metabolic stress on tooth structures when the fetus passes to extrauterine life. AimsThe aim of this research is to determine the existence and thickness of NL in teeth, as it is a legal necessity to indicate the signs of viability at birth in a forensic examination of a fetus or infant case. Study design and subjectsThis research was conducted on 48 lower left and right lateral teeth, which were taken from 24 autopsy cases (46% female and 54% male). Left lateral teeth were sectioned in a vertical plane and right lateral teeth were sectioned in a horizontal plane. The NL thickness was measured with a scanning electron microscope (SEM). These cases comprised three conditions as: 70.3% normal birth, 16.7% caesarean sections, and 12.5% still birth cases under the legal and ethical permission. Outcome measuresThe mean NL thickness of normal birth cases was higher than caesarean cases as 7.7μm and 2.5μm, respectively. Results and conclusionsThe results showed a statistical significance between all birth conditions. NL does not exist in still birth cases (p<0.001). Not only is the presence of NL a sign of live birth, but also its thickness is an indicator of the delivery mode where NL thickness of normal birth was found thicker than the caesarean cases.

An Alternative Method for Flapless Implant Placement and an Immediate Provisional Crown: A Case Report

The aim of this case report is to present a description of bone mapping as an alternative method to determine the dimensions of bone prior to placement of a flapless implant and an immediate provisional crown. The use of a temporary removable partial denture (RPD) or "flipper" during healing following an extraction is not acceptable for some highly demanding patients. As a result, flapless implant placement is gaining popularity because it offers some advantages such as less bleeding, less swelling, and the protection of soft tissue contours. A 65-year-old woman missing a maxillary left lateral incisor was treated using flapless implant placement and an immediate provisional acrylic crown. Under local anesthesia, the bone anatomy was mapped by inserting a standard periodontal probe in the gingiva. By using the recorded measurements, the thickness of soft tissue was removed from the cast. A surgical guide based on this adjusted model was fabricated prior to surgery. The guide was seated on the teeth when actual surgery was performed to facilitate bone drilling and then the implant was placed. Utilizing the previously fabricated acrylic tooth index, the temporary acrylic crown was fabricated on the adjusted temporary metal abutment and delivered to the patient the same day. In this case report the missing maxillary left lateral tooth was restored using flapless implant placement and an immediate provisional single crown. The dimension of the bone at the implant recipient area was determined by an alternative bone mapping method. This case report suggests the use of flapless implant placement using the bone mapping method and immediate provisional crowns for single crowns when esthetics are a high priority and preserving ideal soft tissue contours and papillary heights are critical.

Pathologic tooth deformities in fossil and modern sharks related to jaw injuries

Dental abnormalities in a tiger shark Galeocerdo cuvier and in Carcharoides totuserratus are presented here again, along with some further ones in shark teeth. Comparisons are made with fossil and modern shark teeth abnormalities. A coalescent set of two Squalicorax pristodontus teeth is described. The gibbous shape of the crown is similar to that in S. kaupi, the preceding species of the same lineage. It therefore suggests that the differentiation of the most derived species S. pristodontus may have resulted from kaupi through size increase and development of jaws, becoming more spacious, with teeth getting broader mesio-distally. An abnormal Carcharocles megalodon tooth is described. We regard it as a left lateral tooth from the mandible, whose crown is much deformed. Its features suggest trauma resulting from a feeding accident, maybe through biting the very compact bones of its more likely common prey, Halianassa sirenians. The last case concerns an abnormal Negaprion tooth. The most remarkable differences apart from the normal teeth concern the crown, which is irregular in shape. It shows some torsion, which also occurs in the root. A well-marked notch occurs in the mesial side. The cusp is somewhat labially bent. Trauma on the tooth-forming tissues seems to be responsible for the abnormalities under study. As far as we could ascertain, no lemon-shark dental abnormalities have previously been described. Our results stress that tooth modifications resulting from injuries to the tooth-producing tissues occurred since long ago in similar ways as in extant sharks. Biting prey's hard skeletal parts seems as always the main cause for injuries.