Showing 6 results for Premolar
J. Mahmodian , A. Kowsary , Sh. Javadi-Nejad ,
Volume 11, Issue 4 (8-1998)
Abstract
Eruption is a kind of development move of tooth from the place of its formation to its functional position in the mouth.Time and sequence of permanent's teeth eruption from the point of health diagnosis and orthodontic treatments is very important.Because of this, we decided to evaluate and determine the mean eruption time of canine and premolars from gum penetrations toward occlusion and also their sequence of eruption.The average time of eruptions in this study was higher than other similar studies.Our findings showed that the mean eruption time of canine and premolars in girls is earlier than boys lower canines erupt earlier than upper ones and maxillary premolars erupt before mandibular premolars in boys.
L. Eslamian ,
Volume 15, Issue 4 (1-2003)
Abstract
According to researches, premolar extraction and anterior teeth retraction result in temporomandibular joint disorder due to posterior position of mandible. The aim of this study was to evaluate the effect of premolar extraction on TMJ disorder. In this interventiond study, 4 groups (10 patients for each group) were treated.They were classified as 1- non extraction, 2- extraction of two upper first premolars, 3- extraction of four first premolars, 4- combined extraction groups. Helkimo scores were evaluated before treatment, after treatment, one and two years after treatment. The results were analyzed with ANOVA and paired t-test. At the end of the treatment and two years after treatment in comparison with before treatment, Helkimo score had Significant differentce in all groups (PO.001). In the second year after debanding in comparison with the first year after debanding, no significant differences were seen in each group. No significant difference was seen between the four groups in the final appraisal of TMD. It seems that extraction had no adverse effect on TMD.
V. Talebi , H. Mahmood Hashemi , H. Gahani Hashemi ,
Volume 16, Issue 2 (5-2003)
Abstract
Statement of Problem: One of the easiest and most practical methods to predict the size of permanent canines and premolars, is of Tanaka-Johnston, but their research has been only performed on white skin North Europeans and it should be noted that the size of teeth, in various races, differ from each other.
Purpose: The aim of this study was to determine the validity of Tanaka-Johnston method, in a sample population taken from Ghazvin city.
Materials and Methods: The numbers of 235 pairs of study casts, prepared before any kind of treatment, were selected. The size of lower permanent incisors and permanent canines and premolars of both arches were measured. To analyze the results, "regression analysis" and "t test" were used.
Results: Based on the findings obtained from this study, new prediction equations as Y=12.9+0.4(X) and Y=]0.6+0.5(X) were presented for maxilla and mandible, respectively. However, these equations did not differ from Tanaka-Johnston equations statistically.
Conclusion: Tanaka- Johnston equations can be acceptably applied for the sample population taken from Ghazvin city, if the predictions are not overestimated.
Sara Mogharrabi, Asadallah Ahmadzadeh, Safoura Ghodsi, Farzad Bazmi, Sara Valizadeh,
Volume 33, Issue 1 (7-2020)
Abstract
Background and Aims: Immediate implant placement following tooth extraction is a treatment with many advantages. Alveolar bone preservation after immediate implant, need minimum of 2 mm thickness in buccal bone plate. The aim of this study was to evaluate the thickness of buccal cortical bone of maxillary premolars by Cone Beam Computational Tomography (CBCT) technique.
Materials and Methods: In this descriptive epidemiological study, Cone Beam Computed Tomography image was obtained from 29 patients (male and female) referred to the radiology department of Jundi Shapoor dental school of Ahvaz from 1393 (Mehr) to 1394 (Shahrivar) for implant insertion insertion. The thickness of buccal cortical bone was measured in 3 and 5 mm apical to the CEJ and root apex, perpendicular to the longitudinal axis. All the measurements were done by two oral and maxillofacial radiologists, separately. Data were analyzed by SPSS22 software, using descriptive statistics, and T-test.
Results: The thickness of buccal cortical bone in second premolar was significantly more than 1 mm (P=0.001), but in first premolar, the thickness was close to 1 mm with a non-significant difference (P=0.29).
Conclusion: The results of this study showed that immediate implant insertion could be done in the maxillary second premolar area with more predictability compared to the first premolar area.
Seyed Hadi Hosseini, Fatemeh Ghobadi, Vahid Rezaii, Donya Maleki,
Volume 34, Issue 0 (5-2021)
Abstract
Background and Aims: Knowing the depth and type of the teeth impaction with radiographic approaches can guide the clinicians into selecting the most appropriate treatment and prevent surgical complications. Therefore, the purpose of this article was to evaluate the prevalence of canine and premolar impaction in the digital panoramic view of patients referred to Rasht dental school in 2019.
Materials and Methods: This annalistic-descriptive cross-sectional study comprised patients who attended the Faculty of Dentistry, Rasht, Iran in 2019. Dental records and panoramic radiographs of 500 patients were reviewed retrospectively. Demographic information as well as the type and depth of impaction, involved jaw, and also, the associated pathological lesions were recorded. Data were analyzed with SPSS24 version with significant level of P<0.05.
Results: The findings revealed that among 500 individuals (300 (60%) were females and 200 (40%) were males), 35 individuals (7%) had at least one impacted tooth, 80% of impacted teeth were canines and the others were premolars. The most common impaction type, impaction level, and pathological lesion were mesioangular, B, and carries of the adjacent tooth, respectively. A significant relation was not observed between the type and level of impaction with the involved jaw (P=0.15, P=0.99) and also, the relation between the type of pathological lesion and gender was insignificant (P=0.85).
Conclusion: Functional and esthetic complications of impacted tooth can be prevented or declined by on-time radiographic screening.
Amirhosein Rostami, Seyedali Seyedmajidi, Valiollah Arash, Abbas Ramyar, Nima Hedayati Goodarzi, Amirhosein Ghasemi, Reza Faraji,
Volume 39, Issue 0 (3-2026)
Abstract
Background and Aims: Bimaxillary dentoalveolar protrusion (BDP) is a common orthodontic anomaly characterized by protrusive dental arches and lip prominence. Extraction of the first premolars is a frequently employed treatment approach in these patients. However, the effect of this intervention on Bolton ratios-particularly the overall and anterior ratios-remains unclear. This study aimed to evaluate the impact of first premolar extractions on Bolton ratios in patients with BDP.
Materials and Methods: This experimental study was conducted on archived physical models of 34 Class I patients with BDP and functional lip incompetency (>4 mm) accompanied by lip protrusion, available at the Orthodontics Department of School of Dentistry, Babol, in 2024. All patients had a full complement of teeth from the first incisor to the first molar in each quadrant. After digitizing the models, mesiodistal tooth widths and the overall and anterior Bolton ratios were calculated. Digital simulation of first premolar extraction was performed, followed by reassessment of Bolton ratios. Pre- and post-treatment values were statistically compared using paired t-tests in SPSS (significance level set at 0.05).
Results: Among 34 studied casts, 67.6 % belonged to females. The mean overall Bolton ratio decreased significantly from 90.33 ± 2.23% to 87.72 ± 2.39%, and the anterior ratio declined from 78.19 ± 2.96% to 77.85 ± 3.03% (P<0.001). Additionally, 15 patients exhibited residual space post-treatment, primarily in the mandibular arch.
Conclusion: Based on the results of the present study, first premolar extraction significantly reduced both the overall and anterior Bolton ratios in patients with bimaxillary dentoalveolar protrusion. However, the likelihood of residual space—particularly in the lower arch-should be carefully considered during orthodontic treatment planning to ensure long-term stability and success.
