Accidental displacement of impacted maxillary third molars

3 cases of accidental displacement of maxillary impacted 3rd molars are presented. 2 were displaced into the maxillary sinus and 1 into the infratemporal fossa. The difficulties in locating these displaced teeth are described and demonstrated on a dry skull model. The mode of treatment is discussed.     

Impacted maxillary third molars. Accidental dislocation

During surgical removal of impacted maxillary third molars, many complications may occur. Their accidental displacements in the maxillary sinus or in the infratemporal fossa are not too rare in the common general dentistry. Presenting this case, the Authors want to demonstrate that, when each one of this kind of teeth are well studied before their treatment, many complications can be avoided and, the sooner the dentist is able to solve them when they occur, the better the post-operative course will be.     

Incidence and treatment of complications in patients who had third molars or other teeth extracted

The aim of this study was to compare the incidence of complications after extraction of third molars (M3) or other teeth, and to describe their management. We made a retrospective cohort study of patients having M3 or other teeth extracted, and recorded complications up to two years’ follow-up. A total of 142 complications developed after 2355 procedures (6%) – 7% after extraction of M3 compared with 5% after extractions of other teeth (p = 0.024). The three most common complications were wound infection (2%), pain without apparent cause (<1%), and oroantral communication (<1%). Patients who had M3 extracted were at increased risk of complications compared with those who had other teeth extracted (Odds ratio (OR) 1.5, p = 0.024), particularly for infection (OR 5.9, p < 0.001) and hypoaesthesia (OR 8.4, p = 0.027). Half of all patients with a complication were treated with antibiotics orally. The incidence of postoperative bleeding was 0.6% as a result of suboptimal management of antithrombotic drugs in extractions of teeth other than M3. Finally, optimal treatment of the complications was compared with the available evidence. Prevention and treatment of these complications could reduce the incidence, particularly of bleeding.     

Accidental displacement of impacted maxillary and mandibular third molars.

Displacement of impacted third molars is frequently mentioned in oral and maxillofacial surgery textbooks, but rarely reported. However, should this complication arise in general practice, the clinician should not embark on potentially complicated and hazardous surgical procedures to retrieve the displaced tooth. Administration of prophylactic broad spectrum antibiotics and urgent referral to an oral and maxillofacial surgeon, is recommended.     

Root canal morphology of human maxillary and mandibular third molars

The anatomy of third molars has been described as unpredictable. However restorative, prosthetic, and orthodontic considerations often require endodontic treatment of third molars in order for them to be retained as functional components of the dental arch. The purpose of this study was to investigate and characterize the anatomy of maxillary and mandibular third molars. One hundred fifty maxillary and 150 mandibular extracted third molars were vacuum-injected with dye, decalcified, and made transparent. The anatomy of the root canal system was then recorded. Seventeen percent of mandibular molars had one root (40% of which contained two canals), 77% had two roots, 5% had three roots, and 1% had four roots. Teeth with two roots exhibited highly variable canal morphology, containing from one to six canals, including 2.2% that were "C-shaped." Fifteen percent of maxillary molars had one root, 32% had two roots, 45% had three roots, and 7% had four roots. Teeth with one root demonstrated the most unusual morphology, with the number of canals varying from one to six. An in vivo study of the canal morphology of treated third molars is suggested to provide the practitioner with an understanding of the clinical implications of third molar root anatomy.     

上颌第三磨牙根管形态的显微研究

目的研究上颌第三磨牙根管的解剖形态并寻找牙根与根管之间的对应关系。方法从150颗患者被拔除的上颌第三磨牙中,筛选牙体较完整的融合根30颗和分叉根17颗,利用显微cT扫描后行三维重建,观察其根管全貌,并对根管类型进行统计分析。结果17颗分叉根的根管形态全部为3管型或4管型,其中15颗根管数目与牙根数目一致;30颗融合根则出现了多种根管形态,其根管数目为1～4个不等。结论上颌第三磨牙根管形态变异大,但分叉根的根管形态相对简单,而融合根的根管形态反而复杂,牙根和根管数目往往不一致。     

The surgical-orthodontic management of combined impacted maxillary second and third molars

Background

A correlation between impacted maxillary third molars on the eruption potential of the maxillary second molar has been identified. There is little published evidence available in the literature regarding a treatment modality for this presentation.

Aims 

The aim of this case series is to propose a joint surgical and orthodontic approach for the management of such cases.

Method 

A retrospective search of all patients treated for impacted second and third maxillary molars from 2014 to 2020 revealed 24 cases. Surgical planning was facilitated with the use of a CBCT to help orientate the teeth in 3-D and assess any associated pathology to nearby structures. Twenty-three cases were treated via surgical removal of the impacted third molar and subsequently monitored for spontaneous maxillary second molar eruption.

Conclusion

 All treated cases showed complete or partial spontaneous eruption followed by orthodontic repositioning if required.

     

Fusion of maxillary third and supernumerary fourth molars. Case report

Fusion of teeth is most commonly reported in the deciduous dentition, particularly in the anterior teeth. Recently, additional cases of fusion have also been reported in the mandibular molars of the permanent dentition, and are not considered uncommon. However, reports of the involvement of maxillary molars appear to be particularly rare in the literature. This case is another example of the quite rare phenomenon of fusion of maxillary third and supernumerary fourth molars.     

Patterns of tooth agenesis in Japanese subjects with bilateral agenesis of mandibular second premolars

The aim of this study was to explore the patterns of tooth agenesis in Japanese orthodontic patients with bilateral agenesis of mandibular second premolars. A total of 80 Japanese orthodontic patients with 2 congenitally missing mandibular second premolars were selected as the subjects of this study (experimental group). Another 80 individuals without bilateral agenesis of mandibular second premolars were collected for comparison (control group). The 2 groups were matched with regard to sex. Radiographs, dental casts and records of medical and/or dental treatment were used to identify tooth agenesis. The Chi-square test, odds ratio, and test for equality were used to make statistical comparisons. The prevalence rates of other types of tooth agenesis were significantly higher in the experimental group than in the control group. The occurrence of agenesis of maxillary and mandibular lateral incisors and third molars, and maxillary second premolars was also significantly higher in the experimental group than in the control group. Significantly increased prevalence rates of symmetrical tooth agenesis, with third molars included, and oligodontia were observed in the experimental group. Japanese subjects with bilateral agenesis of mandibular second premolars are at significantly high risk of agenesis of other types of permanent teeth, symmetrical tooth agenesis and oligodontia.     

上颌埋伏阻生第三磨牙78例微创拔除的临床总结

目的评价微创拔除较为困难上颌埋伏阻生第三磨牙的临床效果。 方法2012年1月至2017年3月期间就诊广州市海珠区口腔医院口腔颌面外科诊断为上颌埋伏阻生第三磨牙共计78例,排除拔牙禁忌证,锥形束CT（CBCT）检查评估患牙位置与毗邻重要解剖结构的位置关系,利用微创拔牙器械与方法拔除患牙。术后1周评估微创拔牙方法的效果以及其并发症发生率等。 结果78例微创拔牙手术时间为3~ 45 min,平均13 min。手术期间患者感觉无明显不适,微创拔牙术后不良反应较低,78例均未出现严重并发症的情况。 结论微创拔牙在拔除较为困难的上颌埋伏阻生第三磨牙中具有一定优势,值得临床推广使用。