Humans ; Tooth Extraction ; methods

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

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 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

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

OBJECTIVEThe purpose of this study was to make a comparison between extraction and non-extraction orthodontic treatment results concerning teeth alignment, occlusal relation, facial profile and treatment interval.

METHODS39 extraction-non-extraction borderline cases were selected by 5 orthodontic specialists through reviewing their pre-treatment records. 5 specialists were then asked to rank the results by marking the post-treatment record of each case. And then the samples were divided into different groups according to extraction, non-extraction and extraction pattern by reviewing case history.

RESULTSNo statistically significant difference was found in teeth alignment, overbite and overjet, midline symmetry, lateral occlusal relation and treatment intervals. However, the post-treatment facial profile of extraction groups obtained higher marks from 5 specialists (P = 0.001).

CONCLUSIONWhile both extraction and non-extraction treatment can achieve comparable results in teeth alignment and occlusal relation with equivalent time interval in borderline cases, extraction treatment, whatever extraction of four first premolars or second premolars is performed, can achieve better facial profile.

Child ; Dental Occlusion ; Female ; Humans ; Jaw Relation Record ; Male ; Malocclusion ; therapy ; Orthodontics, Corrective ; methods ; Retrospective Studies ; Tooth Extraction

OBJECTIVETo evaluate the clinical results of immediate implant and immediate restoration and to discuss the applying principles of these techniques.

METHODSFourteen cases underwent immediate implant surgery for 37 dental implants immediately after the teeth or roots were extracted. Among them, 6 cases (14 implants) received immediate restoration after implant placement. The second stage operation and final restoration were performed 4 months on average postoperatively, and the mean follow-up time was 22 months.

RESULTSTwo implants from 1 case were lost at 3 weeks after immediate implant and immediate restoration. The rest cases achieved good clinical results. Accumulative 4-year survival rate was 94.6%.

CONCLUSIONSThe result of immediate implant and immediate restoration is predictable if the cases are properly selected.

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