BACKGROUND Extraction of impacted third molars often leads to severe complications caused by damage to the inferior alveolar nerve(IAN).AIM To proposes a method for the partial grinding of an impacted mandibular third...BACKGROUND Extraction of impacted third molars often leads to severe complications caused by damage to the inferior alveolar nerve(IAN).AIM To proposes a method for the partial grinding of an impacted mandibular third molar(IMM3)near the IAN to prevent IAN injury during IMM3 extraction.METHODS Between January 1996 and March 2022,25 patients with IMM3 roots near the IAN were enrolled.The first stage of the operation consisted of grinding a major part of the IMM3 crown with a high-speed turbine dental drill to achieve sufficient space between the mandibular second molar and IMM3.After 6 months,when the root tips were observed to be away from the IAN on X-ray examination,the remaining part of the IMM3 was completely removed.RESULTS All IMM3s were extracted easily without symptoms of IAN injury after extraction.CONCLUSION Partial IMM3 grinding may be a good alternative treatment option to avoid IAN injury in high-risk cases.展开更多
Background:This study aims to predict the extraction difficulty of mandibular third molars based on panoramic images using transfer learning while employing super-resolution(SR)technology to enhance the feasibility an...Background:This study aims to predict the extraction difficulty of mandibular third molars based on panoramic images using transfer learning while employing super-resolution(SR)technology to enhance the feasibility and validity of the prediction.Methods:We reviewed a total of 608 preoperative mandibular third molar panoramic radiographs from two medical facilities:the First Affiliated Hospital of Zhengzhou University(n=509;456 in the training set and 53 in the test set)and the Henan Provincial Dental Hospital(n=99 in the validation set).We conducted a deep-transfer learning network on high-resolution(HR)panoramic radiographs to improve the longitudinal resolution of the images and obtained the SR images.Subsequently,we constructed models named Model-HR and Model-SR using high-dimensional quantitative features extracted through the Least Absolute Shrinkage and Selection Operator method.The models’performances were evaluated using the receiver operating characteristic curve(ROC).To assess the reliability of the model,we compared the results from the test set with those of three dentists.Results:Model-SR outperformed Model-HR(area under the curve(AUC):0.779,sensitivity:85.5%,specificity:60.9%,and accuracy:79.8%vs.AUC:0.753,sensitivity:73.7%,specificity:73.9%,and accuracy:73.7%)in predicting the difficulty of extracting mandibular third molars.Both Model-HR(AUC=0.821,95%CI 0.687–0.956)and Model-SR(AUC=0.963,95%CI 0.921–0.999)demonstrated superior performance compared to expert dentists(highest AUC=0.799,95%CI 0.671–0.927).Conclusions:Model-SR yielded superior predictive performance in determining the difficulty of extracting mandibular third molars when compared with Model-HR and expert dentists’visual assessments.展开更多
Aims & Objectives: This study was performed to evaluate the incidence, risk factors (age, sex, infection, radiographic difficulty of the extraction, tobacco use) contributing to the development of dry socket and c...Aims & Objectives: This study was performed to evaluate the incidence, risk factors (age, sex, infection, radiographic difficulty of the extraction, tobacco use) contributing to the development of dry socket and clinical features following surgical removal of impacted mandibular third molar. Materials and Methods: The study included 63 patients during period of September 2009 to September 2011 in the age group of 18 to 53 years with impacted mandibular third molars all of which were surgically removed under local anesthesia by the same operator. Following surgery all patients received a single dose of 4 mg corticosteroid intravenously and similar prescriptions for analgesics, antibiotics and postoperative instructions. All patients were reviewed at 3rd and 7th day postoperatively. Results: In this study incidence of dry socket was 6.3%. We also noticed onset of symptom mostly appeared within 48 hours. Postoperatively pain, bare bone and halitosis were the most significant clinical feature at 3rd postoperative day and pain, empty socket and bare bone were most significant clinical feature at 7th postoperative day. Variables like right 3rd molar impaction, patients mean age between 19 - 32 years, female, preoperative infection, radiographically difficult impaction and habitual tobacco users showed a higher incidence of dry socket formation. Conclusion: Incidence of dry socket formation is multifactorial and therefore, there is need to evaluate all factors, with special attentions in handling these patients to reduce the incidence of dry socket formation.展开更多
Middle-mesial canals in mandibular molars are present in the population depending on age, sex and ethnicity. However, limited literature alludes to its prevalence. Troughing procedures may enhance identification, clea...Middle-mesial canals in mandibular molars are present in the population depending on age, sex and ethnicity. However, limited literature alludes to its prevalence. Troughing procedures may enhance identification, cleaning and shaping. This case report expresses the recognition and management of middle-mesial canal in a mandibular second molar of 24 years old Hispanic-Latino male.展开更多
Extraction of the lower third molar is one of the most common procedures performed in oral surgery. In general, impacted tooth extraction involves sectioning the tooth’s crown and roots. In order to divide the impact...Extraction of the lower third molar is one of the most common procedures performed in oral surgery. In general, impacted tooth extraction involves sectioning the tooth’s crown and roots. In order to divide the impacted tooth so that it can be extracted, high-speed air turbine drills are frequently used. However, complications related to air turbine drills may occur. In this report, we propose an alternative tooth sectioning method that obviates the need for air turbine drill use by using a low-speed straight handpiece and carbide bur. A 21-year-old female patient presented to the institute’s dental hospital complaining of symptoms localized to the left lower third molar tooth that were suggestive of impaction. After physical examination, tooth extraction of the impacted left lower third molar was proposed and the patient consented to the procedure. The crown was divided using a conventional straight low-speed handpiece and carbide bur. This carbide bur can easily cut through the enamel of crown. On post-operative day number five, suture was removed and the wound was extremely clear. This technique could minimise intra-operative time and reduce the morbidity associated with air turbine drill assisted lower third molar extraction.展开更多
[Objectives] To shorten the time of removal of the bone embedded mandibular third molar,reduce the complications of tooth extraction,and explore a surgery method of resistance-free removal of the mandibular third mola...[Objectives] To shorten the time of removal of the bone embedded mandibular third molar,reduce the complications of tooth extraction,and explore a surgery method of resistance-free removal of the mandibular third molar. [Methods] A total of 50 patients with bone embedded mandibular third molar needing to be removed were selected. A 45° elevation turbine and a long tungsten steel drill were used to remove the mesial,buccal,and distal resistances. When necessary,tongue side and root resistance was removed,and the third molar was removed when there was basically no resistance around it. The removal time was recorded,followed up for 10 d,and the postoperative reaction was observed. [Results] The bone embedded mandibular third molars were removed for all patients within 15 min,and there was no serious postoperative reaction,all patients showed high satisfaction. [Conclusions]The method of resistance-free removal of the bone embedded mandibular third molar can significantly shorten the removal time,reduce the fear of patients,and ease pain of patients.展开更多
Aim of the study was to evaluate if there is a constant and significant reduction in traumaticity when mas- sively traumatic oral surgical procedures such as the removal of third molars are conducted with only ul- tra...Aim of the study was to evaluate if there is a constant and significant reduction in traumaticity when mas- sively traumatic oral surgical procedures such as the removal of third molars are conducted with only ul- trasonic surgical devices (Piezotomes) expressed in a reduction of postsurgical pain and swelling on the patient’s side since such clinical experiences by the authors suggested this. Since oral surgeons criticize a higher time consumption for surgeries with Piezoto- mes also the objective time consumption was evalu- ated and compared to the traditional methods. Mate- rial and Methods: 56 female and male patients were selected that already underwent a removal of an im- pacted third mandibular molar on one side with rota- ry instruments by bone destructive burring with a still persisting comparable third mandibular molar on the contralateral side complaining about recur- rent pain episodes and were already documented for pain and swelling before. The ultrasonic surgical re- moval with the Piezotome was conducted with a buc- cal osteotomy of the compacta lateral to the impacted third molar, preservation of the resected compacta in saline solution, removal of the third molar by single or multiple dentotomy and full anatomical restitution of the surgical site with the preserved buccal com- pacta. The swelling was documented by kephalome- try 24/48/72 hours and 1 week post surgery, the pain index by the total consumption of ibuprofen-400 mg—tablets. Lesions of the mandible nerve were documented. Netto surgery time was taken from the first incision to the last suture of the procedure. Re-sults: 6 patients had to be excluded from evaluation due to incomplete post surgical follow up. A signify-cant (***, p > 0.999) decrease in pain and swelling of 50% was detected both for the parameters swelling and pain with Piezotome-surgery. No lesions of the mandible nerve were detected with Piezotome sur- gery whereas surgery with rotary instruments re- sulted in 16% hypesthesia at least up to one week. Although netto surgery time was approximately 50% longer when done with the Piezotome at the begin-ning the time consumption normalized with the growing experience of the surgeons back to the time schedule when surgery was performed with rotary instruments revealing no significant differences (-, p < 0.73). Conclusions: The results of this retrospective study suggest that Piezotome-surgery is superior in atraumaticity and soft-tissue safety compared to tra- ditional procedures with burs and grants the patients significantly less post surgical pain and swelling. Al- though—as it is with all new surgical tools and pro- tocols—surgery time is longer at the beginning when purely working with ultrasonic surgical devices time consumption reduces to normal values after a learn- ing curve.展开更多
Background: The surgical removal of impacted mandibular molars represents one of the most prevalent procedures carried out by the oral and maxillofacial surgeon. Despite its prevalence, unusual impaction location of m...Background: The surgical removal of impacted mandibular molars represents one of the most prevalent procedures carried out by the oral and maxillofacial surgeon. Despite its prevalence, unusual impaction location of mandibular molars necessitates alternative extraction approaches. One of the methods described for extraction of deeply impacted molars is the bony lid approach which was first presented for surgical endodontic treatment of mandibular molars. The aim of this study was to evaluate the outcome of the bony lid approach in extracting mandibular molars. In addition, critical clinical key points, new aspects while performing this procedure, indications and contraindications are discussed. Materials and Methods: 9 patients were treated with the bony lid technique. A retrospective analysis of medical charts was conducted to evaluate the results of surgery. Results: The operative technique described in the article was successfully carried out in 12 cases of impacted mandibular molars. No incidence of permanent sensory deficit was recorded. In one patient, an infection mandated the removal of the bony lids. In all other cases the healing process was uneventful. Conclusion: The bony lid technique has many advantages over alternative extraction methods and should be considered as a treatment option in cases of critical proximity between an impacted tooth and the inferior alveolar nerve.展开更多
Background: The over-ambitious use of surgical drills for almost every case of third molar impaction is on the increase in most established oral surgery centers. The purpose of this study was to assess and compare the...Background: The over-ambitious use of surgical drills for almost every case of third molar impaction is on the increase in most established oral surgery centers. The purpose of this study was to assess and compare the severity of post operative symptoms of swelling and pain that accompany the use of surgical drill in the buccal guttering technique and the non application of drill in an alveolar expansion technique. Methods: Consecutive patients with bilateral impacted lower third molars not associated with pericoronitis were included in the study, a total of 10 patients were included in the study. Extraction of both impacted third molars was done consecutively on the same day under local anaesthesia. Post operative morbidities that were assessed clinically are swelling and pain. Results: A total of 10 patients, 70% were females and males were 30%. Age range was 27 - 35 yrs.Out of the eight patients that had the two different techniques, 7 preferred the use of the alveolar expansion technique in which drill was not used. There were statistically significant differences in swellings between these two techniques, (p 0.01). Conclusions: To avoid excessive swelling and pain from over-ambitious cut-ting of soft tissues and drilling of bone, alveolar expansion technique should be considered first in pa-tients with less dense bone.展开更多
We report a case series of ten patients who presented with anterior open bite. The initial evaluation included clinical pictures, lateral cephalometric radiographs and dental casts. They were assessed according to the...We report a case series of ten patients who presented with anterior open bite. The initial evaluation included clinical pictures, lateral cephalometric radiographs and dental casts. They were assessed according to the severity of the open bite and the cause (skeletal or dental). They all underwent orthodontic treatment as an initial step. Five patients with dental open bite underwent molar intrusion using titanium screws and five patients underwent maxillary Le Fort I impaction. We report the mandibular changes associated with these different treatment modalities with improved esthetics.展开更多
BACKGROUND Morphological anomalies of teeth,including talon cusp,dens evaginatus,gemination,fusion,concrescence,root dilaceration,and taurodontism,always involve changes in the enamel,cementum and dentin.Diagnosing co...BACKGROUND Morphological anomalies of teeth,including talon cusp,dens evaginatus,gemination,fusion,concrescence,root dilaceration,and taurodontism,always involve changes in the enamel,cementum and dentin.Diagnosing concrescent teeth through routine clinical examination alone is difficult,and most cases of concrescence are found accidentally during extraction.A definite preoperative diagnosis of concrescence would contribute to a better treatment plan and fewer undesirable complications CASE SUMMARY A 47-year-old woman who complained of left maxillary first molar loss for half a year presented to our department seeking treatment by dental implant restoration.Panoramic radiography and cone-beam computed tomography(CBCT)showed an unclear boundary between the distal root of the second molar and the mesial root of the third molar.The teeth were extracted under local anesthesia,and a definite diagnosis of concrescence was made by histopathological examination.CONCLUSION CBCT is a useful tool for diagnosing and planning the management of tooth concrescence and may be beneficial for reducing unnecessary complications.展开更多
Teeth affect not only oral problems but also facial morphology.In China,there are few reports about the influence of the third molars on the craniofacial morphology of Han youths.Using in vivo imaging software,3D reco...Teeth affect not only oral problems but also facial morphology.In China,there are few reports about the influence of the third molars on the craniofacial morphology of Han youths.Using in vivo imaging software,3D reconstruction of craniofacial CTs were performed on 32 Chinese Han youths without mandibular third molars and 25 Chinese Han youth with full mandibular third molars.The morphology of their mandible and mandibular tissue was measured to identify differences.Among the morphological characteristics of hard tissues,except for∠ANB,people with a full eruption of the mandibular third molars had statistically significantly larger angle indicators than people without the eruption of the third molars.The soft tissue indicators also showed statistically significant discrepancies in terms of morphological facial height,mouth to gnathion distance,lip height,and mouth breadth.The most influential index for mandibular third molars was length of symphysis,followed by the four indicators of soft tissue and mandible length and height.Morphology facial height,mouth to gnathion distance,lip height,and height of symphysis were moderately correlated.The experimental results show that among Han youth in North China,the third molar eruption has a widespread influence on mandibular morphology,especially in angle,length,and height indicators.It also has a certain influence on maxillofacial soft tissue morphology.These results can be applied to future clinical risk assessment of the wisdom teeth and forensic personal identification of the cranial and maxillofacial region.展开更多
The role of third molars in the oral cavity has been extensively studied over the years. Literature includes numerous diagnostic and treatment alternatives regarding the third molars. However, an issue that has not be...The role of third molars in the oral cavity has been extensively studied over the years. Literature includes numerous diagnostic and treatment alternatives regarding the third molars. However, an issue that has not been discussed at the same level is their involvement in orthodontic therapy. The aim of this study is to present a review of the contemporary literature regarding the most broadly discussed aspects of the multifactorial role of third molars in orthodontics and which are of general dental interest too.展开更多
The aim of this study was to investigate the physiological foramen diameter, shape and distance between physiological and anatomical apex of maxillary and mandibular first and second molars. Accurate knowledge of the ...The aim of this study was to investigate the physiological foramen diameter, shape and distance between physiological and anatomical apex of maxillary and mandibular first and second molars. Accurate knowledge of the physiological foramina morphology; thus, inherent mechanical shaping technical hindrances, is decisive when taking the corresponding root canal final preparation decision. The morphological dimensions of a total of 1 727 physiological foramina were investigated by means of micro-computed tomography. Mean narrow and wide(to a high number, oval) diameters of the physiological foramen were 0.24,0.22 and 0.33 mm and 0.33, 0.31 and 0.42 mm in mesiobuccal(MB), distobuccal(DB) and palatal(P) roots in maxillary first molars; 0.24, 0.22 and 0.33 mm and 0.41, 0.33 and 0.44 in MB, DB, and P roots in maxillary second molars. Mandibular first molars showed mean narrow and wide diameters of 0.24 and 0.30 mm and of 0.39 and 0.46 mm in mesial(M) and distal(D)roots; second mandibular molars showed 0.25 and 0.31 mm and 0.47 mm in M and D roots. The mean distance between the physiological foramina and anatomical apex was 0.82, 0.81 and 1.02 mm and 0.54, 0.43 and 0.63 mm in MB, DB and P roots of the maxillary first and second molars, respectively. A mean distance of 0.95 mm(M) and 1.05 mm(D) in the first and0.78 mm(M) and 0.81 mm(D) in the second mandibular molars was observed. Based on the results obtained, assumable recommendations for final preparation size of the physiological foramen were calculated. However, when taking into consideration, the resulting standard deviations of marginal errors must be cautiously considered when taking a final decision in clinical endodontic treatment.展开更多
The aims of the study were to investigate the incidence of C-shaped root canal systems in mandibular second molars in a native Chinese population using radiography and clinical examination under microscope and to comp...The aims of the study were to investigate the incidence of C-shaped root canal systems in mandibular second molars in a native Chinese population using radiography and clinical examination under microscope and to compare the relative efficacies of these methods.For the recognition of C-shaped root canal system,1 146 mandibular second molars were selected and examined.Teeth with C-shaped canal systems were categorized by using the radiographic classification criteria and the modified Melton's method.C-shaped canals were identified in 397(34.64%) mandibular second molars by radiography(type I,31.23%;type II,38.29%;type III,30.48%).Clinical examination showed that 449(39.18%) cases exhibited C-shaped canal systems(C1,22.94%;C2,48.11%;C3a,15.59%;C3b,13.36%).As for the result of the radiographic and clinical combined examination,C-shaped root canals were found in 473(41.27%) mandibular second molars(C1,21.78%;C2,45.67%;C3a,16.70%;C3b,15.86%).The incidence of C-shaped root canal diagnosed by radiographic method was statistically different from that by clinical examination and the combined examination(P,0.05).The study indicated a high incidence of C-shaped canal system in a Chinese population.The combination of microscopic and radiographic examination is an effective method in identifying the C-shaped root canal system.展开更多
BACKGROUND Kissing molars(KMs)are a scarcely reported form of molar impaction in which the occlusal surfaces contact each other within a single dental follicle and the roots point in opposite directions.The direction ...BACKGROUND Kissing molars(KMs)are a scarcely reported form of molar impaction in which the occlusal surfaces contact each other within a single dental follicle and the roots point in opposite directions.The direction of KMs impaction is generally tilted.KMs with vertical direction impaction have not been reported in the literature.CASE SUMMARY A 25-year-old female visited a dentist for right maxillary wisdom teeth extraction and was diagnosed with two vertically impacted KMs in the left mandible on panoramic radiography.After cone-beam computed tomography examination confirmed no secondary complication,the patient chose to undergo observation and regular follow-up.A literature review of KMs revealed that vertical impacted KMs are rare;high-quality evidence regarding their prevalence is still lacking.At present,the causality of KMs is controversial.In this study,we have tried to provide a detailed definition of KMs to allow an accurate evaluation of their prevalence and classification based on their impaction direction which may be related to their pathogenesis.The treatment plan of KMs depends on the condition and location of the affected teeth and associated complications;they may be either directly extracted or treated using a multidisciplinary approach including maxillofacial surgeons and orthodontists.CONCLUSION KMs are a rare clinical condition of impacted teeth with unclear pathogenesis.Vertically impacted KMs were seldom reported.Reasonable definition and classification of KMs can help in the understanding of their causes and prevalence.展开更多
Aim: To confirm the effect of root canal treatment on radix entomolaris. Case: Radix entomolaris was an additional root that located on the distolingual of mandibular first molars. In this case, the radix entomolaris ...Aim: To confirm the effect of root canal treatment on radix entomolaris. Case: Radix entomolaris was an additional root that located on the distolingual of mandibular first molars. In this case, the radix entomolaris was detected clinically and radiographically with root canal configuration such as curves. An awareness and understanding of this unusual root and root canal morphology could contribute to the successful outcome of endodontic treatment. Conclusion: Root canal treatment on this case shows the lack of symptoms and normal radiographic presentation for two months follow-up.展开更多
BACKGROUND The incidence rate of severely curved root canals in mandibular molars is low,and the root canal treatment of mandibular molars with this aberrant canal anatomy may be technically challenging.CASE SUMMARY A...BACKGROUND The incidence rate of severely curved root canals in mandibular molars is low,and the root canal treatment of mandibular molars with this aberrant canal anatomy may be technically challenging.CASE SUMMARY A 26-year-old Chinese female patient presented with intermittent and occlusal pain in the left mandibular second molar.The patient had undergone filling restoration for caries before endodontic consultation.With the aid of cone beam computed tomography(CBCT),a large periapical radiolucency was observed,and curved root canals in a mandibular second molar were confirmed,depicting a severe and curved distolingual root.Nonsurgical treatments,including novel individualized preparation skills and techniques and the use of bioceramic materials as an apical barrier,were performed,and complete healing of the periapical lesion and a satisfactory effect were achieved.CONCLUSION A case of severely curved root canals in a mandibular second molar was successfully treated and are reported herein.The complex anatomy of the tooth and the postoperative effect were also evaluated via the three-dimensional reconstruction of CBCT images,which accurately identified the aberrant canal morphology.New devices and biomaterial applications combined with novel synthesis techniques can increase the success rate of intractable endodontic treatment.展开更多
Objective: The purpose of this study was to detect the prevalence of distolingual(DL) roots in the permanent mandibular molars in a Chinese population by using cone-beam computed tomography(CBCT).Methods : A total of ...Objective: The purpose of this study was to detect the prevalence of distolingual(DL) roots in the permanent mandibular molars in a Chinese population by using cone-beam computed tomography(CBCT).Methods : A total of 500Chinese patients'CBCT images were examined.The incidences and bilateral concurrence rates of DL roots were determined for the permanent mandibular first,second and third molars.The differences between sexes and sides were tested by using Chi-square tests.The antimeric correlations for occurrence of the trait were analyzed with the Spearman's rank order correlation test.Results : The prevalence of 3-rooted mandibular first molars was 31.98%(134 / 419individuals) calculated by individuals,and 25.89%(217 / 838teeth) calculated by teeth.The bilateral concurrence rate was 61.94%.A significant right-side predilection was found in the female group(P=0.025) as well as for both sexes combined(P=0.009).The Spearman's correlations coefficient between antimeres was 0.77(P=0.000).The prevalence of DL roots in the mandibular second and third molars were 2.02%(8 / 396individuals) and 12.10%(19 / 157individuals),respectively.The corresponding bilateral concurrence rate was 12.50% and 35.83%,and the bilateral correlation coefficient was 0.22(P=0.000) and 0.50(P=0.000),respectively.Conclusion : Clinicians should be aware of the high prevalence of the DL roots in the Chinese population.Understanding the pattern of occurrence would be useful for dental treatment.展开更多
文摘BACKGROUND Extraction of impacted third molars often leads to severe complications caused by damage to the inferior alveolar nerve(IAN).AIM To proposes a method for the partial grinding of an impacted mandibular third molar(IMM3)near the IAN to prevent IAN injury during IMM3 extraction.METHODS Between January 1996 and March 2022,25 patients with IMM3 roots near the IAN were enrolled.The first stage of the operation consisted of grinding a major part of the IMM3 crown with a high-speed turbine dental drill to achieve sufficient space between the mandibular second molar and IMM3.After 6 months,when the root tips were observed to be away from the IAN on X-ray examination,the remaining part of the IMM3 was completely removed.RESULTS All IMM3s were extracted easily without symptoms of IAN injury after extraction.CONCLUSION Partial IMM3 grinding may be a good alternative treatment option to avoid IAN injury in high-risk cases.
基金supported by the National Natural Science Foundation of China(U1904145)the Joint Funds for the Innovation of Science and Technology of Fujian province(2019Y9128).
文摘Background:This study aims to predict the extraction difficulty of mandibular third molars based on panoramic images using transfer learning while employing super-resolution(SR)technology to enhance the feasibility and validity of the prediction.Methods:We reviewed a total of 608 preoperative mandibular third molar panoramic radiographs from two medical facilities:the First Affiliated Hospital of Zhengzhou University(n=509;456 in the training set and 53 in the test set)and the Henan Provincial Dental Hospital(n=99 in the validation set).We conducted a deep-transfer learning network on high-resolution(HR)panoramic radiographs to improve the longitudinal resolution of the images and obtained the SR images.Subsequently,we constructed models named Model-HR and Model-SR using high-dimensional quantitative features extracted through the Least Absolute Shrinkage and Selection Operator method.The models’performances were evaluated using the receiver operating characteristic curve(ROC).To assess the reliability of the model,we compared the results from the test set with those of three dentists.Results:Model-SR outperformed Model-HR(area under the curve(AUC):0.779,sensitivity:85.5%,specificity:60.9%,and accuracy:79.8%vs.AUC:0.753,sensitivity:73.7%,specificity:73.9%,and accuracy:73.7%)in predicting the difficulty of extracting mandibular third molars.Both Model-HR(AUC=0.821,95%CI 0.687–0.956)and Model-SR(AUC=0.963,95%CI 0.921–0.999)demonstrated superior performance compared to expert dentists(highest AUC=0.799,95%CI 0.671–0.927).Conclusions:Model-SR yielded superior predictive performance in determining the difficulty of extracting mandibular third molars when compared with Model-HR and expert dentists’visual assessments.
文摘Aims & Objectives: This study was performed to evaluate the incidence, risk factors (age, sex, infection, radiographic difficulty of the extraction, tobacco use) contributing to the development of dry socket and clinical features following surgical removal of impacted mandibular third molar. Materials and Methods: The study included 63 patients during period of September 2009 to September 2011 in the age group of 18 to 53 years with impacted mandibular third molars all of which were surgically removed under local anesthesia by the same operator. Following surgery all patients received a single dose of 4 mg corticosteroid intravenously and similar prescriptions for analgesics, antibiotics and postoperative instructions. All patients were reviewed at 3rd and 7th day postoperatively. Results: In this study incidence of dry socket was 6.3%. We also noticed onset of symptom mostly appeared within 48 hours. Postoperatively pain, bare bone and halitosis were the most significant clinical feature at 3rd postoperative day and pain, empty socket and bare bone were most significant clinical feature at 7th postoperative day. Variables like right 3rd molar impaction, patients mean age between 19 - 32 years, female, preoperative infection, radiographically difficult impaction and habitual tobacco users showed a higher incidence of dry socket formation. Conclusion: Incidence of dry socket formation is multifactorial and therefore, there is need to evaluate all factors, with special attentions in handling these patients to reduce the incidence of dry socket formation.
文摘Middle-mesial canals in mandibular molars are present in the population depending on age, sex and ethnicity. However, limited literature alludes to its prevalence. Troughing procedures may enhance identification, cleaning and shaping. This case report expresses the recognition and management of middle-mesial canal in a mandibular second molar of 24 years old Hispanic-Latino male.
文摘Extraction of the lower third molar is one of the most common procedures performed in oral surgery. In general, impacted tooth extraction involves sectioning the tooth’s crown and roots. In order to divide the impacted tooth so that it can be extracted, high-speed air turbine drills are frequently used. However, complications related to air turbine drills may occur. In this report, we propose an alternative tooth sectioning method that obviates the need for air turbine drill use by using a low-speed straight handpiece and carbide bur. A 21-year-old female patient presented to the institute’s dental hospital complaining of symptoms localized to the left lower third molar tooth that were suggestive of impaction. After physical examination, tooth extraction of the impacted left lower third molar was proposed and the patient consented to the procedure. The crown was divided using a conventional straight low-speed handpiece and carbide bur. This carbide bur can easily cut through the enamel of crown. On post-operative day number five, suture was removed and the wound was extremely clear. This technique could minimise intra-operative time and reduce the morbidity associated with air turbine drill assisted lower third molar extraction.
基金Supported by the People's Livelihood Science and Technology Program of Qingdao City(15-9-2-73-nsh)
文摘[Objectives] To shorten the time of removal of the bone embedded mandibular third molar,reduce the complications of tooth extraction,and explore a surgery method of resistance-free removal of the mandibular third molar. [Methods] A total of 50 patients with bone embedded mandibular third molar needing to be removed were selected. A 45° elevation turbine and a long tungsten steel drill were used to remove the mesial,buccal,and distal resistances. When necessary,tongue side and root resistance was removed,and the third molar was removed when there was basically no resistance around it. The removal time was recorded,followed up for 10 d,and the postoperative reaction was observed. [Results] The bone embedded mandibular third molars were removed for all patients within 15 min,and there was no serious postoperative reaction,all patients showed high satisfaction. [Conclusions]The method of resistance-free removal of the bone embedded mandibular third molar can significantly shorten the removal time,reduce the fear of patients,and ease pain of patients.
文摘Aim of the study was to evaluate if there is a constant and significant reduction in traumaticity when mas- sively traumatic oral surgical procedures such as the removal of third molars are conducted with only ul- trasonic surgical devices (Piezotomes) expressed in a reduction of postsurgical pain and swelling on the patient’s side since such clinical experiences by the authors suggested this. Since oral surgeons criticize a higher time consumption for surgeries with Piezoto- mes also the objective time consumption was evalu- ated and compared to the traditional methods. Mate- rial and Methods: 56 female and male patients were selected that already underwent a removal of an im- pacted third mandibular molar on one side with rota- ry instruments by bone destructive burring with a still persisting comparable third mandibular molar on the contralateral side complaining about recur- rent pain episodes and were already documented for pain and swelling before. The ultrasonic surgical re- moval with the Piezotome was conducted with a buc- cal osteotomy of the compacta lateral to the impacted third molar, preservation of the resected compacta in saline solution, removal of the third molar by single or multiple dentotomy and full anatomical restitution of the surgical site with the preserved buccal com- pacta. The swelling was documented by kephalome- try 24/48/72 hours and 1 week post surgery, the pain index by the total consumption of ibuprofen-400 mg—tablets. Lesions of the mandible nerve were documented. Netto surgery time was taken from the first incision to the last suture of the procedure. Re-sults: 6 patients had to be excluded from evaluation due to incomplete post surgical follow up. A signify-cant (***, p > 0.999) decrease in pain and swelling of 50% was detected both for the parameters swelling and pain with Piezotome-surgery. No lesions of the mandible nerve were detected with Piezotome sur- gery whereas surgery with rotary instruments re- sulted in 16% hypesthesia at least up to one week. Although netto surgery time was approximately 50% longer when done with the Piezotome at the begin-ning the time consumption normalized with the growing experience of the surgeons back to the time schedule when surgery was performed with rotary instruments revealing no significant differences (-, p < 0.73). Conclusions: The results of this retrospective study suggest that Piezotome-surgery is superior in atraumaticity and soft-tissue safety compared to tra- ditional procedures with burs and grants the patients significantly less post surgical pain and swelling. Al- though—as it is with all new surgical tools and pro- tocols—surgery time is longer at the beginning when purely working with ultrasonic surgical devices time consumption reduces to normal values after a learn- ing curve.
文摘Background: The surgical removal of impacted mandibular molars represents one of the most prevalent procedures carried out by the oral and maxillofacial surgeon. Despite its prevalence, unusual impaction location of mandibular molars necessitates alternative extraction approaches. One of the methods described for extraction of deeply impacted molars is the bony lid approach which was first presented for surgical endodontic treatment of mandibular molars. The aim of this study was to evaluate the outcome of the bony lid approach in extracting mandibular molars. In addition, critical clinical key points, new aspects while performing this procedure, indications and contraindications are discussed. Materials and Methods: 9 patients were treated with the bony lid technique. A retrospective analysis of medical charts was conducted to evaluate the results of surgery. Results: The operative technique described in the article was successfully carried out in 12 cases of impacted mandibular molars. No incidence of permanent sensory deficit was recorded. In one patient, an infection mandated the removal of the bony lids. In all other cases the healing process was uneventful. Conclusion: The bony lid technique has many advantages over alternative extraction methods and should be considered as a treatment option in cases of critical proximity between an impacted tooth and the inferior alveolar nerve.
文摘Background: The over-ambitious use of surgical drills for almost every case of third molar impaction is on the increase in most established oral surgery centers. The purpose of this study was to assess and compare the severity of post operative symptoms of swelling and pain that accompany the use of surgical drill in the buccal guttering technique and the non application of drill in an alveolar expansion technique. Methods: Consecutive patients with bilateral impacted lower third molars not associated with pericoronitis were included in the study, a total of 10 patients were included in the study. Extraction of both impacted third molars was done consecutively on the same day under local anaesthesia. Post operative morbidities that were assessed clinically are swelling and pain. Results: A total of 10 patients, 70% were females and males were 30%. Age range was 27 - 35 yrs.Out of the eight patients that had the two different techniques, 7 preferred the use of the alveolar expansion technique in which drill was not used. There were statistically significant differences in swellings between these two techniques, (p 0.01). Conclusions: To avoid excessive swelling and pain from over-ambitious cut-ting of soft tissues and drilling of bone, alveolar expansion technique should be considered first in pa-tients with less dense bone.
文摘We report a case series of ten patients who presented with anterior open bite. The initial evaluation included clinical pictures, lateral cephalometric radiographs and dental casts. They were assessed according to the severity of the open bite and the cause (skeletal or dental). They all underwent orthodontic treatment as an initial step. Five patients with dental open bite underwent molar intrusion using titanium screws and five patients underwent maxillary Le Fort I impaction. We report the mandibular changes associated with these different treatment modalities with improved esthetics.
基金Supported by the Applied Basic Research Program of the 920th Hospital of the Joint Logistics Support Force,No.2019YGB15。
文摘BACKGROUND Morphological anomalies of teeth,including talon cusp,dens evaginatus,gemination,fusion,concrescence,root dilaceration,and taurodontism,always involve changes in the enamel,cementum and dentin.Diagnosing concrescent teeth through routine clinical examination alone is difficult,and most cases of concrescence are found accidentally during extraction.A definite preoperative diagnosis of concrescence would contribute to a better treatment plan and fewer undesirable complications CASE SUMMARY A 47-year-old woman who complained of left maxillary first molar loss for half a year presented to our department seeking treatment by dental implant restoration.Panoramic radiography and cone-beam computed tomography(CBCT)showed an unclear boundary between the distal root of the second molar and the mesial root of the third molar.The teeth were extracted under local anesthesia,and a definite diagnosis of concrescence was made by histopathological examination.CONCLUSION CBCT is a useful tool for diagnosing and planning the management of tooth concrescence and may be beneficial for reducing unnecessary complications.
基金supported by Biological Anthropology Innovation Team Project of JZMU(Grant No.JYLJ201702)Liaoning Distinguished Professor Project(Grant No.LNTP20183501&LNTP201418701)。
文摘Teeth affect not only oral problems but also facial morphology.In China,there are few reports about the influence of the third molars on the craniofacial morphology of Han youths.Using in vivo imaging software,3D reconstruction of craniofacial CTs were performed on 32 Chinese Han youths without mandibular third molars and 25 Chinese Han youth with full mandibular third molars.The morphology of their mandible and mandibular tissue was measured to identify differences.Among the morphological characteristics of hard tissues,except for∠ANB,people with a full eruption of the mandibular third molars had statistically significantly larger angle indicators than people without the eruption of the third molars.The soft tissue indicators also showed statistically significant discrepancies in terms of morphological facial height,mouth to gnathion distance,lip height,and mouth breadth.The most influential index for mandibular third molars was length of symphysis,followed by the four indicators of soft tissue and mandible length and height.Morphology facial height,mouth to gnathion distance,lip height,and height of symphysis were moderately correlated.The experimental results show that among Han youth in North China,the third molar eruption has a widespread influence on mandibular morphology,especially in angle,length,and height indicators.It also has a certain influence on maxillofacial soft tissue morphology.These results can be applied to future clinical risk assessment of the wisdom teeth and forensic personal identification of the cranial and maxillofacial region.
文摘The role of third molars in the oral cavity has been extensively studied over the years. Literature includes numerous diagnostic and treatment alternatives regarding the third molars. However, an issue that has not been discussed at the same level is their involvement in orthodontic therapy. The aim of this study is to present a review of the contemporary literature regarding the most broadly discussed aspects of the multifactorial role of third molars in orthodontics and which are of general dental interest too.
文摘The aim of this study was to investigate the physiological foramen diameter, shape and distance between physiological and anatomical apex of maxillary and mandibular first and second molars. Accurate knowledge of the physiological foramina morphology; thus, inherent mechanical shaping technical hindrances, is decisive when taking the corresponding root canal final preparation decision. The morphological dimensions of a total of 1 727 physiological foramina were investigated by means of micro-computed tomography. Mean narrow and wide(to a high number, oval) diameters of the physiological foramen were 0.24,0.22 and 0.33 mm and 0.33, 0.31 and 0.42 mm in mesiobuccal(MB), distobuccal(DB) and palatal(P) roots in maxillary first molars; 0.24, 0.22 and 0.33 mm and 0.41, 0.33 and 0.44 in MB, DB, and P roots in maxillary second molars. Mandibular first molars showed mean narrow and wide diameters of 0.24 and 0.30 mm and of 0.39 and 0.46 mm in mesial(M) and distal(D)roots; second mandibular molars showed 0.25 and 0.31 mm and 0.47 mm in M and D roots. The mean distance between the physiological foramina and anatomical apex was 0.82, 0.81 and 1.02 mm and 0.54, 0.43 and 0.63 mm in MB, DB and P roots of the maxillary first and second molars, respectively. A mean distance of 0.95 mm(M) and 1.05 mm(D) in the first and0.78 mm(M) and 0.81 mm(D) in the second mandibular molars was observed. Based on the results obtained, assumable recommendations for final preparation size of the physiological foramen were calculated. However, when taking into consideration, the resulting standard deviations of marginal errors must be cautiously considered when taking a final decision in clinical endodontic treatment.
基金supported by the grant from the Independent Innovation Foundation of Shandong University of China (No. 2011JC019)the grant of Science and Technique Development Foundation of Shandong province(2010G0020230)
文摘The aims of the study were to investigate the incidence of C-shaped root canal systems in mandibular second molars in a native Chinese population using radiography and clinical examination under microscope and to compare the relative efficacies of these methods.For the recognition of C-shaped root canal system,1 146 mandibular second molars were selected and examined.Teeth with C-shaped canal systems were categorized by using the radiographic classification criteria and the modified Melton's method.C-shaped canals were identified in 397(34.64%) mandibular second molars by radiography(type I,31.23%;type II,38.29%;type III,30.48%).Clinical examination showed that 449(39.18%) cases exhibited C-shaped canal systems(C1,22.94%;C2,48.11%;C3a,15.59%;C3b,13.36%).As for the result of the radiographic and clinical combined examination,C-shaped root canals were found in 473(41.27%) mandibular second molars(C1,21.78%;C2,45.67%;C3a,16.70%;C3b,15.86%).The incidence of C-shaped root canal diagnosed by radiographic method was statistically different from that by clinical examination and the combined examination(P,0.05).The study indicated a high incidence of C-shaped canal system in a Chinese population.The combination of microscopic and radiographic examination is an effective method in identifying the C-shaped root canal system.
基金Supported by Strategic Cooperation Project between Sichuan University and Luzhou Municipal Government,No. 2018CDLZ-14Aba Tibetan and Qiang Autonomous Prefecture Science and Technology Bureau,No. 21YYJSYJ0052
文摘BACKGROUND Kissing molars(KMs)are a scarcely reported form of molar impaction in which the occlusal surfaces contact each other within a single dental follicle and the roots point in opposite directions.The direction of KMs impaction is generally tilted.KMs with vertical direction impaction have not been reported in the literature.CASE SUMMARY A 25-year-old female visited a dentist for right maxillary wisdom teeth extraction and was diagnosed with two vertically impacted KMs in the left mandible on panoramic radiography.After cone-beam computed tomography examination confirmed no secondary complication,the patient chose to undergo observation and regular follow-up.A literature review of KMs revealed that vertical impacted KMs are rare;high-quality evidence regarding their prevalence is still lacking.At present,the causality of KMs is controversial.In this study,we have tried to provide a detailed definition of KMs to allow an accurate evaluation of their prevalence and classification based on their impaction direction which may be related to their pathogenesis.The treatment plan of KMs depends on the condition and location of the affected teeth and associated complications;they may be either directly extracted or treated using a multidisciplinary approach including maxillofacial surgeons and orthodontists.CONCLUSION KMs are a rare clinical condition of impacted teeth with unclear pathogenesis.Vertically impacted KMs were seldom reported.Reasonable definition and classification of KMs can help in the understanding of their causes and prevalence.
文摘Aim: To confirm the effect of root canal treatment on radix entomolaris. Case: Radix entomolaris was an additional root that located on the distolingual of mandibular first molars. In this case, the radix entomolaris was detected clinically and radiographically with root canal configuration such as curves. An awareness and understanding of this unusual root and root canal morphology could contribute to the successful outcome of endodontic treatment. Conclusion: Root canal treatment on this case shows the lack of symptoms and normal radiographic presentation for two months follow-up.
基金Supported by Natural Science Foundation of Hunan Province,No.S2021JJQNJJ1682Changsha Municipal Natural Science Foundation,No.kq 2014215.
文摘BACKGROUND The incidence rate of severely curved root canals in mandibular molars is low,and the root canal treatment of mandibular molars with this aberrant canal anatomy may be technically challenging.CASE SUMMARY A 26-year-old Chinese female patient presented with intermittent and occlusal pain in the left mandibular second molar.The patient had undergone filling restoration for caries before endodontic consultation.With the aid of cone beam computed tomography(CBCT),a large periapical radiolucency was observed,and curved root canals in a mandibular second molar were confirmed,depicting a severe and curved distolingual root.Nonsurgical treatments,including novel individualized preparation skills and techniques and the use of bioceramic materials as an apical barrier,were performed,and complete healing of the periapical lesion and a satisfactory effect were achieved.CONCLUSION A case of severely curved root canals in a mandibular second molar was successfully treated and are reported herein.The complex anatomy of the tooth and the postoperative effect were also evaluated via the three-dimensional reconstruction of CBCT images,which accurately identified the aberrant canal morphology.New devices and biomaterial applications combined with novel synthesis techniques can increase the success rate of intractable endodontic treatment.
文摘Objective: The purpose of this study was to detect the prevalence of distolingual(DL) roots in the permanent mandibular molars in a Chinese population by using cone-beam computed tomography(CBCT).Methods : A total of 500Chinese patients'CBCT images were examined.The incidences and bilateral concurrence rates of DL roots were determined for the permanent mandibular first,second and third molars.The differences between sexes and sides were tested by using Chi-square tests.The antimeric correlations for occurrence of the trait were analyzed with the Spearman's rank order correlation test.Results : The prevalence of 3-rooted mandibular first molars was 31.98%(134 / 419individuals) calculated by individuals,and 25.89%(217 / 838teeth) calculated by teeth.The bilateral concurrence rate was 61.94%.A significant right-side predilection was found in the female group(P=0.025) as well as for both sexes combined(P=0.009).The Spearman's correlations coefficient between antimeres was 0.77(P=0.000).The prevalence of DL roots in the mandibular second and third molars were 2.02%(8 / 396individuals) and 12.10%(19 / 157individuals),respectively.The corresponding bilateral concurrence rate was 12.50% and 35.83%,and the bilateral correlation coefficient was 0.22(P=0.000) and 0.50(P=0.000),respectively.Conclusion : Clinicians should be aware of the high prevalence of the DL roots in the Chinese population.Understanding the pattern of occurrence would be useful for dental treatment.
