Humans ; Tooth Extraction ; methods

OBJECTIVETo investigate the influence of different crown cutting mode on operation time and post-operation trauma in extracting the mandible third molar by dental drilling system.

METHODSAccording to different impaction types, the patients were divided into vertical impaction, horizontal impaction, and mesioangular impaction groups. The operation time, mouth opening, swelling, and pain degrees were recorded during traditional extraction, crown "T"-shaped cutting, crown three section cutting, and crown-root cutting in the extraction of mandibular wisdom teeth.

RESULTSIn the vertical impaction group, the operation time, the degree of swelling, limitation of mouth opening and the pain degree were (8.2 ± 2.5) min, (14.7 ± 2.0) mm, (3.9 ± 2.4) mm and 3.4 ± 1.8, respectively using crown cutting, and (14.0 ± 2.7) min, (18.2 ± 1.9) mm, (9. 7 ± 3.6) mm and 6.9 ± 2.3 using traditional extraction method (P < 0.05). In the horizontal impaction group, the operation time, degree of swelling, limitation of mouth opening and pain degree (14.0 ± 2.0) min, (19.2 ± 3.9) mm, (9.5 ± 2.5) mm, 5.6 ± 1.7 respectively using crown "T"-shaped cutting, and (18.0 ± 3.1) min, (23.6 ± 3.5) mm, (9.8 ± 2.7) mm and 8.5 ± 2.3 using crown three section cutting. There was significant difference in operation time, degree of swelling and pain (P < 0.05), but no significant difference in the limitation of mouth opening (P > 0.05). In mesioangular impaction group, operation time, degree of swelling, limitation of mouth opening and pain degree were (10.2 ± 2.6) min, (18.4 ± 2.9) mm, (6.4 ± 2.5) mm and 4.8 ± 1.8, respectively using "T"-shaped cutting, and (15.0 ± 3.5) min, (18.9 ± 3.0) mm, (7.0 ± 3.7) mm and 7.6 ± 2.3 using crown- root cutting. The operation time and pain degree were significantly different (P < 0.05), but not different in limitation of mouth opening and swelling degree (P > 0.05).

CONCLUSIONSDifferent impaction types of wisdom teeth should choose different cutting mode. Vertical impacted tooth uses distal crown cutting. "T"-shaped cutting is preferred with horizontal impaction. According to the angle and depth of the mesioangular impaction, "T"-shaped cutting or the crown-root cutting can be selectively used.

Humans ; Mandible ; Molar ; Molar, Third ; Tooth Crown ; Tooth Extraction ; methods ; Tooth Root ; Tooth, Impacted

OBJECTIVETo investigate the influences of varying lingual traction forces on the space-closing speed in a typodont model.

METHODSForty-two Angle Class I standard typodont models of bimaxillary teeth protrusion were divided into 7 equal groups. Four regions of the model were paired to groups, and in the odd-numbered models, the top left and bottom left regions served as the experimental group and the top right and bottom right regions as the control group; in the even-numbered models, the regions in the model were grouped oppositely. In the experimental group, the space was closed by niti wire extension spring in the buccal ridge combined with lingual elastic traction of 0, 5, 10, 15, 20, 25 and 30 g. In the control group, the space was closed by exclusive niti wire extension spring in the buccal ridge. The space-closing speed were analyzed in all the groups.

RESULTSThe space-closing speed was significantly lower in the control group than in the experimental groups with lingual traction forces of 5, 10, 15, 20 and 25 g (P<0.05), but a traction force of 30 g resulted in a significantly lower speed than that in the control group (P<0.05). The space closing speed was the greatest in the experimental group with a traction force of 15 g (P<0.05).

CONCLUSIONNiti wire extension spring in the buccal ridge combined with lingual elastic traction results in faster space-closing speed than traditional exclusive niti wire extension spring. The speed is the fastest by applying 15 g lingual traction, which is also associated with the lowest slip resistance.

Dental Models ; Dental Stress Analysis ; Tooth Extraction ; methods ; Traction

Adolescent ; Humans ; Male ; Tooth Ankylosis ; etiology ; surgery ; Tooth Extraction ; methods ; Tooth Root ; Wounds and Injuries ; complications

BACKGROUNDS: Insufficient intermaxillary space is caused by non-restoration following tooth extraction in the past, and this involves eruption of the opposing teeth and changes of the arch structure. Such cases are difficult just by a simple prosthetic approach, and diversified treatment plans should be established. Among these, posterior maxillary segmental osteotomy (PMSO) is an efficient treatment option than extraction of opposing teeth as it surgically repositions multiple erupted teeth and alveolar bone. PMSO can preserve the natural teeth; therefore, it is being regarded as a treatment method which can improve insufficient intermaxillary space significantly. CASE PRESENTATION: In this case report, the first patient received PMSO in order to place an implant in the mandibular edentulous space after decreased vertical dimension is restored, and the second patient received PMSO along with orthodontic treatment to obtain the intermaxillary space and balance the interarch molar width. CONCLUSION: PMSO is the treatment of choice when occlusion is compromised in the presence of decreased vertical dimension or arch length discrepancy.
Humans ; Methods ; Molar ; Orthognathic Surgery ; Osteotomy* ; Tooth ; Tooth Extraction ; Vertical Dimension

OBJECTIVETo compare the effects between mini-screw implant and transpalatal arch (TPA) on dentofacial morphology in extraction cases.

METHODSForty-two cases were divided into two groups. One group (n = 19) had been treated with mini-screw implants and the other group (n = 23) treated with TPA as anchorage control. Sliding technique was used to close extraction space in the two groups. Cephalometric analysis was performed before and after the treatment. The data were analyzed by using independent-samples t test.

RESULTSIn the mini-screw implant group, the maxillary incisors were retracted (7.05 +/- 1.89) mm and intruded (1.71 +/- 2.33) mm, The maxillary first molars were distalized (0.45 +/- 3.32) mm and intruded (1.74 +/- 2.66) mm. While in the TPA group, the upper incisors were retracted (4.59 +/- 1.78) mm and extruded (0.93 +/- 1.77) mm. The maxillary first molars were moved (1.65 +/- 1.87) mm mesially and extruded (0.52 +/- 1.59) mm. All the relevant results between the two groups were significantly different (P < 0.05).

CONCLUSIONSAs orthodontic anchorage, mini-screw implants were different from TPA. Mini-screw implant could not only retract the upper incisors but also slightly intrude upper incisors and upper molars.

Bone Screws ; Cephalometry ; Humans ; Incisor ; Maxilla ; Molar ; Orthodontic Anchorage Procedures ; Tooth Extraction ; Tooth Movement Techniques ; methods

Objective: To evaluate the effect of the application of a self-developed three-dimensional visualized model of impacted tooth for surgical extraction in undergraduate oral experimental teaching. Methods: Forty-one undergraduates majoring stomatology of Tongji University from 2018 [19 males and 22 females, aged (22.4±0.8) years] were enrolled and randomly divided into the conventional group and the experimental group. Students of the conventional group (21 students including 8 males and 13 females) received a teaching protocol for the surgical extraction of impacted tooth including theoretical lectures, watching operation videos, and operating on head-simulator teaching systems. Students of the experimental group (20 students including 11 males and 9 females) received an additional training of resistance assessment and surgical extraction using the three-dimensional visualized model of impacted tooth before operating on the head simulators. After class, a questionnaire survey was carried out among students, and the operation results on the head simulators were evaluated by the teacher. Results: The results of the questionnaire showed that the students in the experimental group were rated higher than those in the traditional group in terms of being able to imagine the relationship between impacted teeth and adjacent structures (U=114.00, P=0.006), avoiding damage to adjacent teeth (U=87.00, P<0.001) and inferior alveolar nerve during tooth extraction (U=111.50, P=0.006), and being more confident in clinical operations in the future (U=120.00, P=0.013). According to the evaluation results of tooth extraction on the head simulators, there was no significant difference in the operation time between the two groups (U=138.50, P=0.056). In the experimental group, 5% (1/20) caused adjacent tooth loosening and 15% (3/20) caused the excessive bone defect, which was less than those in the traditional group [38% (8/21) and 48% (10/21), respectively] (P=0.021; P=0.043). There was no significant difference in the incidence of grinding out the deep bone of impacted teeth between the two groups (P=0.232). Conclusions: The application of three-dimensional visualized model of impacted tooth for surgical extraction in undergraduate oral experimental teaching had achieved good results and was worth popularizing.
Female ; Humans ; Male ; Molar, Third/surgery* ; Operative Time ; Students ; Tooth Extraction/methods* ; Tooth, Impacted/surgery*

Cone-Beam Computed Tomography ; methods ; Humans ; Risk Factors ; Tooth Extraction ; Tooth Fractures ; diagnosis ; diagnostic imaging ; etiology ; therapy ; Tooth Root ; injuries

OBJECTIVETo evaluate the clinical result of immediate implant.

METHODS32 cases underwent immediate implant surgery for 59 implants simultaneously when the teeth or roots extracted. 55 implants were placed with bone grafts or bone substitutes. The second stage operation were performed in the sixth month and ceramic crown were fixed in the seventh to eighth month postoperatively, the follow up were mean 39 months.

RESULTSOne implant was lost. Bone resorption of alveolar crest was observed in 4 implants. Mean resorption was 2 mm.

CONCLUSIONSThe result of immediate implant is predictable, the advantages are avoiding the alveolar bone resorption after teeth extraction, implant could be placed in an ideal position; less operation trauma, good esthetics results.

Adult ; Dental Implantation, Endosseous ; methods ; Female ; Follow-Up Studies ; Humans ; Male ; Middle Aged ; Tooth Extraction ; Tooth Socket ; Treatment Outcome

OBJECTIVETo evaluate the clinical results of minimally invasive extraction without flap reflection and immediate implant placement with single-stage surgical procedure.

METHODSTwenty-one patients (23 single-tooth implants) were included in the study. Eight fractured teeth and 15 residual roots in the maxillary anterior region were extracted without flap reflection and implants placed immediately. Special gingival former was connected at the same time of implant placement with single-stage surgical procedure, final prostheses were restored after 6 months. The follow-up time was from 13 months to 51 months (mean: 27.6 months) after final restoration. Clinical and radiographic study were conducted, the interproximal papillae were analyzed according to Jemt's classification and the level of soft-tissue margin and buccal soft tissue color were evaluated according to Fürhauser's method.

RESULTSAll 23 implants acquired osseointegration, and the level of marginal bone at the mesial and distal aspects of all implants were stable. The mesial and distal papilla index score of 3 were observed in 18 implant sites, the papilla index score of 2 in 5 implant sites. Harmonious relationship of gingival margin between peri-implant restorations and adjacent natural teeth was observed in 15 implant sites. The color of buccal soft tissue matched that of the adjacent natural teeth in 18 implant sites, 5 sites showed minor discrepancies. All the patients were satisfied with the final restoration.

CONCLUSIONSMinimally invasive extraction without flap reflection and immediate implant placement with single-stage surgical procedure is a sensitive technique. Many factors may affect the final results and the strict control of indication is the key factor.

Dental Implantation, Endosseous ; methods ; Dental Implants, Single-Tooth ; Esthetics, Dental ; Female ; Gingiva ; Humans ; Male ; Postoperative Period ; Tooth Extraction