上颌前部埋伏多生牙的定位及手术进路

目的 分析上颌前部埋伏多生牙X线片定位的准确性。方法 对236例上颌前部埋伏多生牙采用偏心投射法拍摄定位牙片，对定位牙片把握性较小的病例，辅助拍摄轴向咬合片和头颅侧位定位片，以验证定位牙片的准确性，以此决定多生牙拔除的手术进路。结果 本组342颗埋伏多生牙采用偏心投射法拍摄定位牙片，其定位的准确性与术中情况完全一致，定位牙片定位可疑时，其可靠性也得到了轴向咬合片和头颅侧位定位片的验证。结论 定位牙片仍可视为一种可信的上颌前部埋伏多生牙的定位方法，可为多生牙的拔除提供相应的手术进路。     

正畸治疗中上颌前牙区埋伏多生牙的定位和拔除

目的：探讨埋伏多生牙的定位与拔除方法。方法：临床门诊患者50例，通过定位X线牙片结合临床检查，分析判断埋伏牙的位置，确定手术进路，然后拔除。结果：50例患者经术前定位，4例位于唇侧，38例位于腭侧，8例位于牙列中，与术中所见一致，无损伤邻牙及伤口感染等并发症发生。结论：通过定位X线牙片对埋伏多生牙进行定位是一种简便易行的方法，便于选好手术进路。     

儿童埋伏多生牙临床分析

<正> 儿童混合牙列期因埋伏多生牙易导致多种错(牙合)畸形影响乳恒牙的正常替换,甚至形成含牙囊肿,故常需要及早拨除。然而考虑患儿心理学特点,做到术前准确定位,最大限度地减少手术创伤,就显得非常重要。本文对231例患儿上颌埋伏多生牙的临床分析如下:     

数字化断层片在颌骨埋伏多生牙临床定位中的应用

目的:评价数字化断层片在颌骨埋伏多生牙临床定位中的应用价值。方法:对在全景片或其他检查中发现的埋伏多生牙病例,行数字化断层片检查,以显示埋伏多生牙的阻生情况。结果:埋伏多生牙患者163例,共计179颗牙,数字化断层片能清楚显示埋伏牙的形态、位置及与邻牙的关系。结论:数字化断层片是一种较好的埋伏牙临床定位方法。     

上前牙轴向咬Huo片对埋伏多生牙的定位探讨：附146例分析

上颌前区区埋伏多生牙在口腔临床上较为常见。要拔除这些埋伏多生牙，术前需进行Ｘ线摄片定位，了解埋伏的位置、确定手术切口部位与摘除方向。国内目前均采用心投照来进行定位，但实际应用时受Ｘ线角度改变和牙片放置时产生的弯曲度，Ｘ线影像会出现变形，不易作出正确的判断。我科自１９８５年以来，采用上前牙轴向咬Ｈｕｏ片对１４７例上颌前牙区埋伏多生牙患者进行摄片定位，与临床手术结果相符率达１００％。     

颌骨侧位曲面断层片在上颌骨埋伏多生牙定位中的应用:25例报道

目的：探讨全景机颌骨侧位曲面断层片在上颌骨埋伏多生牙定位中的应用价值。方法：对25例上颌骨埋伏多生牙患者采用ORTHOPHS全景机行侧位曲面断层片，分析、判断埋伏多生牙的位置，采取不同的手术径路拔除埋伏多生牙。结果：(1)颌骨埋伏多生牙侧位曲面断层定位精确；(2)颌骨侧位曲面断层能显示牙弓与多生牙的关系：(3)颌骨侧位曲面断层片能显示多生牙的牙体及牙根的形态。结论：颌骨侧位曲面断层片对颌骨埋伏多生牙的定位具有重要价值。     

上颌埋伏多生牙的定位与临床治疗分析

目的 探讨埋伏多生牙的定位与手术处理.方法 选取门诊患者79例,通过定位X线牙片、上颌骨侧位断层片及螺旋CT结合临床检查,分析判断埋伏牙的位置,选择合适的处理方法.结果 79例患者经术前定位,用根尖片水平定位者58例,采用颌骨侧位断层片定位者11例,采用螺旋CT定位者5例,术前判断均与术中所见一致.根据患者不同特点采用相应麻醉方法,依术前定位采用相应的手术入路,所有多生牙均顺利拔除.结论 定位X线牙片、上颌骨侧位断层片单独应用,必要时结合螺旋CT,可以对埋伏多生牙进行精确定位,选择合适的手术入路及麻醉方法,利于多生牙的拔除.     

上颌中切牙埋伏阻生的X线影像诊断

目的研究埋伏阻生的上颌中切牙的定位、牙齿的方向及阻生的原因等。方法对矫治的263例上颌中切牙埋伏阻生患者治疗前的全颌曲面断层片、头颅侧位片、上颌咬合片、根尖片进行读片研究。结果上颌中切牙埋伏阻生的X线影像直观、立体定位准确。结论4类X线片单独或结合使用可满足埋伏阻生的上颌中切牙的诊断需要。     

正畸治疗中上颌埋伏多生牙的手术拔除

目的 探讨正畸治疗中上颌埋伏多生牙的定位及手术拔除。方法 对21例上颌前部埋伏多生牙采用临床检查，偏心投射拍摄法拍摄定位牙片，辅以头颅侧位片、全景片判断其三维位置．凭此采用不同的手术进路拔除患牙。结果 21例埋伏多生牙经X线片判断5例偏屑侧，13例偏腭侧．3例位于中间，与术中情况一致。拔牙创一期愈合。结论 定位牙片结合头颅侧位片、全景片可视为一种可靠的上颌前部埋伏多生牙的定位方法，并可指导手术进路。     

上前牙轴向咬■片对埋伏多生牙的定位探讨（附146例分析）

上颌前牙区埋伏多生牙在口腔临床上较为常见。要拔除这些埋伏多生牙,术前需进行Ｘ线摄片定位,了解埋伏的位置、确定手术切口部位与摘除方向。国内目前均采用偏心投照来进行定位,但实际应用时受Ｘ线角度改变和牙片放置时产生的弯曲度,Ｘ线影像会出现变形,不易作出正确的判断。我科自１９８５年以来,采用上前牙轴向咬片对１４６例上颌前牙区埋伏多生牙患者进行摄片定位,与临床手术结果相符率达１００％。上颌前牙轴向咬片对埋伏多生牙定位影像直观,定位诊断准确,是一种可靠的定位方法。     

A comparison of restoration longevity in maxillary and mandibular teeth

This study determined if the survival time of restorations in maxillary and mandibular teeth differed in a group of 71 patients. The 1,232 restorations were placed by a dental school clinic in a 29-year period. There were no significant systematic differences in the survival time of restorations in maxillary and mandibular molars, premolars, and canines. Maxillary and mandibular incisors show significant differences in survival patterns. Of the mandibular restorations available for follow-up, 71% were still intact after 26 years.     

Human bite force discrimination using specific maxillary and mandibular teeth

The purpose of this study was to determine whether performance differences existed in subjects' self-generated bite force discrimination ability using maxillary and mandibular central incisors, canines, premolars and first molars. Two separate studies were conducted: (i) to assess whether performance differences existed in subjects' bite force discrimination ability using central incisors and premolars; (ii) to compare subjects' performance on bite force discrimination using central incisors, canines and first molars. Assessment of bite force was measured using a specially designed strain gauge scale allowing subjects to visually monitor when their biting force equalled a preset resistance. Resistance forces of 500, 1000 and 3000 g were selected as standards. Subjects were presented with a series of paired resistance settings, one at a time, the first of each pair being the standard and the second being the comparator setting of a predetermined amount. This paired-comparisons procedure was continued until the subjects' difference limen (DL) value (the threshold of discrimination between two forces) could be established. The first study revealed no significant (P greater than 0.05) overall difference in subjects' bite force discrimination ability relative to specific teeth. In contrast, in the second study a significant difference (P less than 0.05) was identified in subjects' performance relative to specific teeth; subjects' performed better using central incisors compared to first molars. In both studies, subjects' performance was significantly better (P less than 0.05) using the 500 g standard compared to the 3000 g standard in the first study, and compared to the 1000 g standard in the second study. No significant differences (P greater than 0.05) were observed between the performance of males and females in either study.     

Occlusal‐supporting ability of individual maxillary and mandibular teeth

This study aimed to analyse occlusal force, area and pressure for individual maxillary and mandibular teeth by assessing their occlusal‐supporting abilities. Ninety‐nine subjects (49 men and 50 women; average age, 24·7 ± 3·4 years; range, 20–37 years) performed maximal voluntary clenching twice for 3 s in both the intercuspal position and the intercuspal position with sliding movement from edge‐to‐edge occlusion, with a pressure‐sensitive sheet placed between the maxillary and mandibular dental arch. Occlusal force, area and pressure of individual teeth were calculated by colour development in the pressure‐sensitive sheet with special analytical equipment and software. Occlusal contact condition of individual teeth was confirmed using the intra‐occlusal record. All data were analysed using unpaired Student's t‐test, Kruskal–Wallis test and Scheffe's test for multiple comparisons with a significance level of P < 0·05. The occlusal pressure in the intercuspal position with sliding movement from edge‐to‐edge occlusion was adopted as the representative occlusal‐supporting ability for each individual tooth, although there were, in part, statistically significant differences in the effects of laterality, performance and gender. Overall, the occlusal pressure increased gradually from the central incisor, peaked at the canine or first premolar and decreased sharply–and significantly (P < 0·01)–towards the second molar. We conclude that the occlusal pressure of individual teeth can be used as an indicator of occlusal‐supporting ability. This is therefore proposed as a possible suitable parameter for epidemiologic research, specifically for verifying the relationship between occlusal‐supporting ability and status of residual periodontal ligament support.     

Determination of approximate size of maxillary anterior denture teeth when mandibular anterior teeth are present. Part III: Relationship of maxillary to mandibular central incisor widths

The average width of a natural maxillary central incisor is 8.92 mm. This value is determined from the results of three studies of natural dentitions. The average width of a mandibular central incisor is 5.5 mm. The average ratio produced by dividing the average maxillary central incisor width by the average mandibular incisor width is 1.62. The factor of 1.5 times the width of a mandibular central incisor produces a maxillary central incisor width that is too narrow. The width of a mandibular central incisor plus half the width of the mandibular lateral incisor also produces a maxillary central incisor width that is too narrow. There may be a tendency to undersize the maxillary prosthetic dentition. The ratio of 1.62 can be used to select the appropriate width for a missing maxillary central incisor when given the width of the mandibular central incisor. This ratio of 1.62 is also valuable to verify the dimension of a selected artificial maxillary central incisor when the patient complains that the tooth is too large. If substitutions or adjustments are made in the mold, the desired canine-to-canine measurement produced by the ratio range of 1.3 to 1.38 reported in Parts I and II of this study should be maintained.     

Golden proportion assessment between maxillary and mandibular teeth on Indian population

PURPOSE

This study evaluated the existence of golden proportion between the widths of the maxillary and mandibular anterior teeth in Indian population.

MATERIALS AND METHODS

The clinical tooth width measurements were recorded with the digital vernier calipers on 576 patients of both sexes in the age group of 21 - 30 years. Flexible ruler was used to determine the width of maxillary and mandibular anterior teeth on the patients by the same operator. The data obtained was statistically analyzed using paired student t-test (α=.05).

RESULTS

The golden proportion was not found between the width of the right central and lateral incisors in 53% of women and 47% of men. The results revealed the golden percentage was rather inconstant in terms of relative tooth width.

CONCLUSION

The golden proportion is an inappropriate method to relate the successive widths of the maxillary anterior teeth in Indian population.     

关节镜直视下取出误入上颌窦的牙或牙根

目的：介绍一种微创取出进入上颌窦内牙或牙根的方法。方法：2004年3月～2005年2月期间．3例患者在外院拔除上颌磨牙或牙根时，牙或牙根意外进入上颌窦，其中男l例，女2例；平均年龄36．5岁(28-40岁)；l例为左侧上颌第三磨牙，另外2例为上颌第一磨牙牙根。术前全景片证实上颌窦内有高密度异物。经上颌窦前壁开窗．在关节镜直视下取出进入上颌窦的牙或牙根。结果：关节镜直视下成功取出3例误入上颌窦的牙或牙根，术后创口均一期愈合，无任何并发症发生。结论：关节镜直视下取出误入上颌窦的牙或牙根是可行的，具有创伤小、视野清楚、操作时间短等优点；但须具有经过关节镜专门培训的人员方可进行。     

Influence of mandibular free-end partial edentulism on the force exerted on maxillary anterior teeth

PurposeThe purpose of this study was to determine the influence of mandibular free-end partial edentulism and the wearing of removable partial dentures in the partially edentulous area on the force exerted on maxillary anterior teeth.MethodsA commercially available jaw model with exchangeable teeth was used. Seven experimental conditions of mandibular free-end edentulism were set up and a distal extension removable partial denture to replace missing posterior teeth was fabricated. Strain gauges were attached to the root surface of the maxillary left central incisor, canine, first premolar and first molar, and the force exerted on them was calculated based on the calibration coefficient. An occlusal load of 49 N was applied and the forces were compared with the Kruskal–Wallis test (P < 0.05).ResultsThe force exerted on the maxillary anterior teeth increased significantly as the number of remaining teeth decreased. The force exerted on the maxillary anterior teeth decreased significantly with use of a removable partial denture.ConclusionsWhen the number of remaining teeth decreases in mandibular free-end partial edentulism, the burden on the maxillary anterior teeth increases. Our findings suggest that for patients with mandibular free-end partial edentulism, wearing a removable partial denture is effective in preserving the remaining teeth by reducing excessive stress.     

Dimensions of the dentogingival unit in maxillary anterior teeth: a new exploration technique (parallel profile radiograph)

This study sought to develop and evaluate a radiographic exploration technique (parallel profile radiograph [PPRx]) for measuring the dentogingival unit on the buccal surfaces of anterior teeth, and to provide additional information on the dimensions of the dentogingival unit in humans. In 88 periodontally healthy individuals, a PPRx was made of the maxillary left central incisor. Over these images, the components of the dentogingival unit were measured. PPRx was a highly reproducible exploratory technique. Mean dentogingival measurements on the buccal surfaces of the teeth were 2.05 +/- 0.87 mm for distance between the CEJ and bone crest; 2.00 +/- 0.72 mm for biologic width; 1.75 +/- 0.24 mm for thickness of connective tissue attachment; 1.12 +/- 0.24 mm for thickness of free gingiva at its base; 0.45 +/- 0.20 mm for thickness of bone plate at crest level; and 1.41 +/- 0.62 mm for gingival overlap on enamel surface. A statistically significant relationship was observed between free gingival width and thickness of connective attachment, and the depth of the gingival sulcus. These results corroborate the notion that the dimensions of the dentogingival unit are highly variable in humans. The thicknesses of both the connective tissue attachment and free gingiva, however, showed less variability than did the thickness of the bone crest, distance between CEJ and bone crest, and biologic width. The results suggest that gingival dimensions are correlated to dentogingival unit dimensions.