Relationship of the incisive papilla to the maxillary central incisors.

The average distance between the most anterior point of the maxillary central incisors and the most posterior point of the incisive papilla was 12.454 mm with a standard deviation of 3.867 mm. This distance was measured when these two points were projected on a plane which was parallel to the reference plane formed by the tips of three interdental papillae; i.e., the papilla between two central incisors (A), between the first and second molars on the right side (R), and on the left side (L). The average error incurred due to inconsistency of the method employed was less than 3% or less than 0.372 mm for the position of the central incisor. It is believed that the application of this anatomic relation can provide a reliable point for arranging and checking the position of the anterior maxillary teeth for complete dentures.     

Relationship of the maxillary central incisors and canines to the incisive papilla

Four hundred and thirty dentulous casts in normal alignment and Angle's Class I Relationship were examined. The results indicated a relationship between arch shape and the intercanine line with particular reference to the way the latter passed through the incisive papilla. The suggestion is made that in the preliminary location of the anterior teeth during construction of full dentures, the average distance of incisors and canines from the incisive papilla could be used as starting points.     

Relationship of the maxillary canines to the incisive papilla

The positioning of denture teeth in a completely edentulous patient is dependent on many factors. Anatomic landmarks are frequently valuable in complete denture fabrication. The topography of the palatal soft tissue in relationship to tooth position in dentate patients may be an aid in the placement of denture teeth. By using casts formed from irreversible hydrocolloid impressions, 50 subjects were examined to determine the orthographic distance from the posterior of the incisive papilla to a line intersecting the distal contact points of the maxillary canines. In 92% of subjects the posterior point of the incisive papilla was approximately 3 mm anterior to the line between the distal points of the canines. Neither gender, age, nor maxillary tooth arch form affected this distance.     

Duplicating maxillary complete dentures

A technique for duplication of a maxillary complete denture has been presented. This technique requires no special equipment and can be easily completed in the dental office.     

Processing changes in maxillary complete dentures

A technique that allows for comparison of undercuts palatal thickness, and double curing has been described for measurement of curing changes in acrylic resin dentures. The technique involves a precision cast and denture positioner in front of the x-ray tube and the transfer of a lead foil strip from cast to denture. Radiographs made of this strip are projected at X20 magnification, and subsequent tracings are measured and superimposed to note shrinkage and contour changes.     

切牙管与上颌中切牙位置关系的定量研究

目的 本研究旨在通过研究切牙管与上颌中切牙之间的位置关系,以期为临床治疗及后续研究提供借鉴和参考。方法 选取76例正在进行正畸治疗的成人患者,以PP平面为参考平面,在正中矢状面上定义以下三个测量水平,此三个水平均与PP平面平行。N水平：鼻腭孔高度水平;R水平：上颌中切牙牙根根尖高度水平;I水平：切牙孔高度水平。定义以下测量项目：N水平切牙管唇侧牙槽骨板厚度（NT）;R水平切牙管唇侧牙槽骨板厚度（RT）;I水平切牙管唇侧牙槽骨板厚度（IT）。N水平切牙管宽度（NW）;R水平切牙管宽度（RW）;I水平切牙管宽度（IW）;上颌中切牙根尖距离（R R）;R水平UR1到切牙管距离（RRD）;R水平UL1到切牙管距离（RLD）;I水平UR1到切牙管距离（IRD）;I水平UL1到切牙管距离（ILD）。在CBCT图像上对以上指标进行测量,并对结果进行统计学分析。结果 RRD大于IRD;RLD大于ILD,有统计学差异（P<0.05）。RRD与RLD;IRD与ILD,无统计学差异（P＞0.05）。NW小于RW;RW小于IW,有统计学差异（P<0.05）。NT大于RT,有统计学差异（P<0.05）;NT与IT之间无显著性差异（P＞0.05）;RT与IT之间无显著性差异（P＞0.05）。结论 U1根尖至切牙管平均距离仅为3.5 mm;U1在I水平牙根至切牙管平均距离仅为2.4 mm,应注意在上颌前牙内收时有可能导致牙根根尖及牙根舌侧面的吸收。并且当上颌前牙内收尤其配合压低移动时,应注意有可能造成牙根近中邻面的吸收。     

Clinical deformation of maxillary complete dentures

A study of strain-gauge behaviour in two groups of complete denture wearers was completed. The groups consisted of seven satisfied subjects and eight dissatisfied. Six linear strain gauges were used on each denture and functional strain was recorded in the maxillary dentures during maximum bites and empty-mouth chewing. The strain values reported varied a little between the two groups of subjects. The strain values reported agreed generally with those reported previously and demonstrate the complex straining behaviour of complete dentures in function.     

Leiomyomatous hamartoma of the incisive papilla

A case of unusual hamartoma in a six-year-old otherwise healthy Brazilian girl is reported, with emphasis on histological and immunohistochemical features. A mass observed in the incisive papilla was detected whose appearance was similar to congenital epulis or fibroma. Histological findings showed interlacing fascicles of large spindle cells resembling smooth muscle cells. Immunohistochemical staining for desmin and for smooth-muscle actin was positive. The histological diagnosis was leiomyomatous hamartoma, based on clinical and microscopic observations.     

Technique for remounting removable partial dentures opposing maxillary complete dentures

A technique for fabricating a removable partial denture remount cast has been described. This method requires no additional time with the patient and is easily accomplished in the office.     

Tissue pressure under complete maxillary dentures.

This preliminary report has shown the following interesting points: (1) Measurements of tissue pressures beneath dentures are possible using the Sanborn 350 recorder. (2) Stable dentures produce high pressures on the supporting tissues and transmit these pressures from region to region, varying with how the patient uses the dentures. (3) Most often, an opposite large or negative pressure immediately followed the production of positive pressure at the same site beneath the denture. Thus, each movement actually traumatizes the tissue twice. (4) Nonmasticatory pressures produced under dentures are as great as or greater than masticatory pressures. (5) Wave forms for each biting maneuver or sound produced can be charted and are typical for each patient, probably representing denture movement. (6) Swallowing unassociated with eating or drinking produced very high positive and very low negative pressures, giving the greatest ranges of pressures recorded in this experiment. (7) Smoking (recorded in only one patient) also produced a great range of pressures. (8) Sticky foods such as cheddar cheese produced greater negative pressures than the other foods tested. (9) The one patient with natural teeth opposing his denture gave much more uniform and lower pressures than did the patients with complete dentures. (10) This method allows visualization of pressure movement under dentures. The effect of these continually occurring, nonmasticatory, induced pressure changes and pressure waves beneath the dentures may well be of greater significance than that of mastication.     

Morphologic evaluation of the incisive canal and its proximity to the maxillary central incisors using computed tomography images

Objective:To evaluate the morphologic features and the relative position of the incisive canal with regard to the maxillary incisor roots using computed tomography (CT).Materials and Methods:Morphologic evaluation of the incisive canal and its proximity to the maxillary central incisors were measured using CT images of 38 adults with skeletal and dental class I normal occlusion. Linear measurements were performed on the axial cross-sectional images corresponding to three vertical levels, the palatal opening of the incisive canal (L1), midlevel between the opening level and the root apex of the maxillary central incisors (L2), and the root apex of the maxillary central incisors (L3).Results:The percentage of subjects with an incisive canal width greater than the interroot distance of the central incisors was 86.8% and 63.2% at levels L1 and L2, respectively. The anteroposterior distance between the maxillary incisor roots and the boarder of the incisive canal was approximately 5–6 mm at levels L1 and L2.Conclusion:The anteroposterior distance between the maxillary central incisor roots and the incisive canal was approximately 5–6 mm. More than 60% of the subjects had an incisive canal width greater than the interroot distance. Evaluation of the proximity of the incisive canal to the maxillary incisors, along with its dimensional characteristics, may be helpful when a considerable amount of maxillary retraction is planned.     

Investigation of the strain produced in maxillary complete dentures in function

An experiment has been completed to investigate the strain levels obtained on polymethylmethacrylate dentures in function when biting and swallowing. The use of stacked, rosette strain gauges enabled the magnitude of strain in the material underlying the gauge to be calculated and, in addition, the direction of the principle maximum and minimum strain was also calculated. Strain in the denture base was measured in biting and swallowing with a normal occlusion, when the occlusal contact area was narrowed, and with the rosette gauges.