LOCAL COMPLICATIONS OF WISDOM TEETH EXTRACTIONS: A LITERATURE REVIEW

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Loran Omer

5th year, group 11

LOCAL COMPLICATIONS OF WISDOM TEETH

EXTRACTIONS: A LITERATURE REVIEW

Master’s thesis

Supervisor

Professor, DMD, PhD Gintaras Juodžbalys

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LITHUANIAN UNIVERSITY OF HEALTH SCIENCES MEDICAL ACADEMY

FACULTY OF ODONTOLOGY

CLINIC OF MAXILLOFACIAL AND ORAL SURGERY

LOCAL COMPLICATIONS OF WISDOM TEETH EXTRACTIONS: A LITERATURE REVIEW

Master’s Thesis

The thesis was done by student……… Supervisor………

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FINAL MASTER’S THESIS IS CONDUCTED AT THE DEPARTMENT OF ORAL AND MAXILLOFACIAL SURGERY

STATEMENT OF THESIS ORIGINALITY

I confirm that the submitted Final Master’s Thesis (title) LOCAL COMPLICATIONS OF WISDOM TEETH EXTRACTIONS: A LITERATURE REVIEW

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3. I did not use any additional sources that are not listed in the Thesis, and I provide a complete list of references.

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ABBREVIATIONS

IAN - inferior alveolar nerve LN - lingual nerve

AO - alveolar osteitis

OAC - oroantral communication NIH - national institute of health MC - mandibular canal

CT - computed tomography

CBCT - cone-beam computed tomography OPG - orthopantomogram

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SUMMARY

Relevance and aim: Extraction of the third molars either erupted or impacted is one of the most common procedures performed by oral surgeons in daily practice. However, specific complications are associated with this surgical procedure which must be thoroughly understood and anticipated by the practitioner. This review aims to assess all the possible local complications associated with wisdom teeth surgery and to understand which factors contribute to the appearance of the complications.

Materials and methods: The search of the articles included in this review was done using databases MEDLINE/PubMed and Cochrane library from January 2010 till November 2020 in the English language. The search was conducted according to the inclusion criteria, with the main request being clinical trials on patients that require wisdom teeth extraction.

Results: From a total of 92 articles that were found, 4 met this review’s requirements. Various complications were reported, from which only local complications were extracted. A further division was made to separate them into two groups, the most common and less common ones. Patients’ parameters were also selected and of great importance in this review for further understanding of what patient group is more prone to complications.

Conclusion: It is not possible to outline one single complication which occurs most often. However, there is a group of complications that includes alveolar osteitis, oroantral fistula, pain, sensory nerve damage and root fractures, which are reported to appear regularly during third molar surgeries.

Keywords:postoperative complications; tooth, impacted; tooth extraction; Surgical Flaps; molar, third; Retrospective Studies

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11

INTRODUCTION

The removal of mandibular and maxillary third molars is one of the most common surgical procedures carried out by oral surgeons in daily practice [1-7]. Many interventions are done successfully, but in some cases, as in other kinds of surgeries, complications might appear [3]. The operator must be fully aware of any possible issues, and a very detailed pre-operative treatment plan must be prepared and accompanied by a radiological examination of the area [1,2].

The incidence of complications is linked to some factors that include age, gender, presence of pericoronitis, poor oral hygiene status, intake of oral contraceptives, degree of retention, and spatial position of the impacted third molar. However, age, degree of retention, and spatial position are the most prominent ones [1-5,8]. The incidence of complications appearing in young patients till 30 years of age is 11.8%, while in patients older than 30 years, the risk increases up to 21.5% [13]. A peculiar association between age and complications is due to the fact that in adult patients that are older than 30 years of age, the bone density is increasing, making osteotomy a longer and more complicated process than usual [4,5,8]. Besides that, the bone structure in the younger population is more elastic, highly vascularized, and has a higher healing potential [13].

It has been demonstrated that a higher complication rate is associated with molars that have a higher degree of impaction [8]. Some impaction of wisdom teeth can present symptoms, while other cases can stay asymptomatic. In the mandibular arch, the prevalence of wisdom teeth impaction in the population is between 20% and 30%, and in some cases, it can cause facial asymmetry and infection [6].

In Europe, third molar impaction happens in approximately 73% of young individuals. Usually, these teeth erupt between 17 and 21 years of age, but the third molar eruption also varies with race. For example, in Nigeria, mandibular third molars may erupt as early as 14 years of age, while in Europe, they may erupt until 26 years of age [20]. Complications can be intraoperative as iatrogenic injury to hard and soft tissues, bleeding, root fracture, iatrogenic fracture of the maxilla and mandible, and displacement of the teeth into adjacent spaces. Complications can also appear after the surgical procedure.

Postoperative complications associated with wisdom teeth removal are alveolar osteitis (AO), sensation disorders, trismus, prolonged bleeding, swelling, and periodontal complications on the distal side of the second molars [6,9].

Studies also suggest that females are more often prone to develop postoperative complications than males [7,13,20]. The operator must pay attention to the maxilla and mandible’s anatomical peculiarities, significantly impacting the possible surgery difficulties.

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In the upper jaw, the maxillary antrum is related to the maxilla’s most common complication, known as oroantral communication (OAC) [2]. In the lower jaw, a critical feature is the inferior alveolar nerve (IAN). The lower third molars’ position should be very carefully evaluated with an orthopantomogram (OPG) or a cone-beam computed tomography (CBCT) to observe the possible interference with the mandibular canal (MC) [1]. Damage to the IAN and lingual nerve (LN) can result in temporary and permanently altered sensations. In the case of LN injury, the tongue’s loss of sensation corresponds with the side of LN injury.

Regarding IAN, there can be chin involvement, but this is not always the case. Sensation loss of the lower lip is mostly experienced by patients suffering from IAN. Often patients also suffer from paraesthesia. Another important aspect is the experience of the surgeon and the surgical technique implemented. The more traumatic the teeth’ surgical removal is, the higher the risk of postoperative complications such as pain, oedema, and trismus [4]. This is the reason why it has always been an issue to reduce postoperative complications for oral surgeons. Horizontal mattress sutures can be used in impacted mandibular third molar surgery to improve primary wound healing and, therefore, to reduce the risk of wound dehiscence and dry socket [6].

The complication rate associated with wisdom teeth surgery ranges from 2.6% and 4.6% up to 30.9% and can develop intra or postoperatively [3,8]. All the papers underline the importance of informing the patient about the possible difficulties before wisdom teeth surgery.

Since this procedure is performed routinely in oral surgery departments worldwide and still has a very high rate of complications, this review tends to highlight some of the most critical aspects of this topic by engaging the following aim and tasks:

Aim - This review aims to assess all the possible local complications associated with wisdom teeth surgery and to understand which factors contribute to the appearance of the complications.

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13 The tasks of the following systematic review are:

1. To find out the most commonly occurring complications, particularly for the upper and lower jaw. 2. To evaluate if there is a connection between the level of impaction and the complication risk.

3. To discover if increased age leads to a higher risk of having complications. 4. To determine whether the complication rate is higher in impacted wisdom teeth removal compared to erupted ones.

Hypothesis: Are local complications occurring more in the mandible or maxilla?

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1. SELECTION CRITERIA OF THE STUDIES. SEARCH METHODS AND

STRATEGY

1.1. Protocol and registration

The review was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement for reporting systematic reviews [30]. Details are described in Annex 1.

1.2. Focus question

The focus question was developed according to the Patient, Intervention, Comparison and Outcome (PICO) framework described in Table 1.

What local complications can be expected due to impacted and non-impacted third molar extraction, and what local complications are the most often occurring?

Table 1. PICO framework.

Patients Patients in need of either erupted or impacted wisdom teeth removal

Intervention Simple or surgical extraction

Comparison Complication rate between the maxilla and mandible Outcome Severity of complications associated with the difficulty

degree of surgical intervention

Focus question What local complications can be expected due to impacted and non-impacted third molar extraction, and what local complications are most often occurring? Hypothesis Are local complications occurring more in mandible or

maxilla?

1.3. Types of publications

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15 1.4. Types of studies

In this review were included clinical trials published from January 2010 till November 2014.

1.5. Information sources

PubMed and Cochrane library databases were used to search the articles.

1.6. Type of population

Patients in need of wisdom teeth extraction without the restriction of age or sex but that did not suffer from any uncontrolled systemic disorders.

1.7. Disease definition

Extractions of third molars impacted or erupted became a usual surgery nowadays due to the destructive effect on the adjacent second molars because of their distal position in the dental arch or as prophylaxis in case of impaction to avoid cysts, tumours or other related pathologies.

1.8. Literature search strategy

Articles search was undertaken in electronic databases PubMed and Cochrane library for publications including third molar surgeries with the main focus on the possible local complications. For the search, the following keywords were used in combinations “postoperative complications” AND “tooth, impacted” AND “tooth extraction” AND “Surgical Flaps” AND “molar, third” AND “pain, postoperative”. The time limit selected for the publications was from 1st of January 2010 till 30th of November 2020. The PRISMA flow diagram for study selection is presented in Figure 1.

1.9. Inclusion criteria

-Clinical trials with more than 50 wisdom teeth extractions. -Studies published in the English language.

-Studies that focus on the complications that appear intra and postoperatively, but not only on the management and prevention.

-Studies on patients that require third molar extractions, including impacted and non-impacted third molar cases.

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-Extraction of third molars due to various reasons, including caries, cysts, benign or malignant tumours, impaction and orthodontic reasons.

1.10. Exclusion criteria -Studies on animals. -Case reports.

-Studies that focus on extraction complications on teeth other than third molars. -Extra or intraoral trauma as an extraction cause.

-Patients with severe and uncontrolled systemic disorders such as diabetes mellitus, cardiovascular disorders and blood coagulation disorders.

1.11. Data extraction

According to the aim and tasks of the review in the form of variables, data extracted from the articles were according to the aim and tasks of the review. Data Items extracted are listed below.

1.12. Data items

• “Authors” - it unveils the author of the publications. • “Year” - it unveils the year of publications.

• “Type of study” - indicates the type of involved articles.

• “Patient count” - number of patients that have undergone third molar surgery. • “Mean age” - represents the mean age of patients involved in all the studies.

• “Male/female ratio” - represents the number of females and males involved in the clinical trials. • “Number of extractions” - the total amount of extracted wisdom teeth from the upper and lower

jaw.

• “Extractions in maxilla” – the number of third molars extracted only from the upper jaw. • “Extractions in mandible” – the number of third molars extracted only from the lower jaw. • “Simple extractions” - extractions where only forceps are required, non-invasive.

• “Surgical extractions” - the invasive type of extractions requiring flaps elevation, osteotomy, roots separation.

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17 • “Most common local complications; mandible” - a group of complications mentioned by all the

studies to appear in the lower jaw.

• “Complications” - total number of complications resulting from wisdom teeth extraction from both jaws.

1.13. Risk of bias assessment

National Institute of Health (NIH) Assessment Tool for Observational Cohort and Cross-Sectional studies were used to determine the four retrospective cohort studies’ quality included in this review [29]. The assessment consists of 14 criteria to which the answer can be “yes”, “no”, “not applicable”, “not reported”, and “cannot determine”. Based on the presented answers, each article was evaluated as good, fair or poor. In the case of the latter, an explanation must be given why this is the case. This tool does not assess the risk of bias as either high or low, but according to the studies’ quality, bias can be determined. This assessment was performed only to include articles with good quality and filter out the ones with fair quality.

1.14. Synthesis of results

Appropriate data of interest on the previously stated data items were collected and organized into four tables according to the total number of patients, total amount of extractions, and the number of extractions performed, particularly in the upper and lower jaw (table 1). In the second table are summarized the total amount of complications, simple and surgical extractions, as well as the mean age of the patients. Table 3 and 4 provides information about the most common complications selected from the studies.

1.15. Statistical analysis

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2. SYSTEMIZATION AND ANALYSIS OF DATA

2.1. Study selection

The PRISMA flow diagram chart was used to perform the extraction of the publications for this review. In total, 92 articles were obtained during the search. After the removal of duplicates, 67 remained. After screening the titles and abstracts of these articles, 61 were excluded, and six remained to be assessed for eligibility. Two publications did not meet the inclusion criteria and aim of the review and therefore were excluded in the last step of the diagram. At the end of the search, four articles met the set criteria and were included in the review. A summary of the data search is presented in Figure 1.

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19 2.2. Exclusion of studies

One of the excluded articles did not meet the inclusion criteria because it did not provide any information about the number of extracted teeth [5]. The second excluded article did not meet this review’s aim because it was not focused on the surgery complications but their prevention by using different suturing techniques [6].

2.3. Quality assessment of the included studies

Table 1. NIH Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies.

+ yes; - no; NA= not applicable; NR= not reported.

According to this assessment results, all the articles included in this review have good quality [1-4]. Some aspects of the evaluation criteria did not apply to the selected articles and their aim, respectively. For example, blinding of the assessors was not possible in any of the studies due to the type of surgery. Local complications are assessed by the surgeon immediately if it is happening during the surgery or the follow-up if it is a postoperative complication. Other criteria as “different levels of exposure” and “repeated exposure” are not relevant to the given clinical trials, and they are assessed in patients with different types of disorders and more extensive and complex treatment. The criteria were missing or not reported in the studies, but this did not increase bias.

Study Year Checklist

Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Q10 Q11 Q12 Q13 Q14 Sigron et al. [1] 2014

₊

_-

₊

NA

₊

NA

₊

NA

_-

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2.4. Study characteristics

This review analyses four retrospective studies published from January 2010 to November 2014 [1-4]. The characteristics of the study are summarized in Table 1.

Table 1. Characteristics of the study included in the review, number of patients and extractions.

Author Year Total number of extractions Number of extractions in maxilla Number of extractions in mandible Number of patients Sigron et al.[1] 2014 1.199 - 1.199 1.001 Pourmand et al. [2] 2014 1.562 1.562 - 1.212 Contar et al. [3] 2010 1.699 836 863 588 Osunde et al. [4] 2014 330 - 330 250

A total of 4.790 maxillary and mandibular wisdom teeth extractions were analyzed from a pool of 3.051 patients. Only one article included in the study contained extractions performed in both jaws [3], while two articles discussed the removal of wisdom teeth performed in the lower jaw [1,4], and 1 study analyzed extractions only in the maxilla [2]. However, the total amount of extracted teeth in the upper jaw (n=2.398) is slightly higher than in the lower jaw (n=2.392). Information about patients’ general health was recorded only in one article [3], and no information was provided in all the others [1,2,4]. In the mentioned article, patients with present medical conditions were not included in the study [3].

Table 2. Patient’s characteristics, complications and type of intervention.

Author Male/female ratio Average age (years) Number of complications Number of simple extractions Number of surgical extractions Sigron et al. [1] 54.5% males 45.5% females 29±12 101 401 798 Pourmand et al. [2] 54% males 46% females 11-82 106 1.019 543 Contar et al. [3] 260 males 328 females 14-54 59 376 1.324

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21 Osunde et al. [4] 104 males 146 females 18-54 30 - 330

Table 2 represents other parameters of the studies. A total of 296 complications were found during the surgical procedure. Overall, most of the patients undergoing this procedure were between 20 and 30 years of age, and more males (n=1.564) than females (n=1.487) were involved. Data were extracted from the articles regarding the type of intervention as being either simple or surgical. Simple extractions stand for removing the third molar by using forceps only, without any surgical intervention, and surgical extractions involve more invasive actions such as flaps elevation, osteotomy or separation of the roots. All articles provided information about this topic except one [4] since all the extracted teeth were impacted, and it automatically demands a surgical approach.

Table 3. Representation of the most common complications diagnosed in the maxilla.

Author Oroantral communication Root fracture Pourmand et al.

[2]

n=38 n=36

Contar et al. [3] n=1 n=5

Given this study’s research aim, data regarding the main complications with a higher rate of appearing in daily practice was extracted. In the upper jaw, two complications appeared to be mentioned in both articles [2,3]. OAC was named the most common, and root fracture was the second most common [2]. The other paper reported the complications according to the level of surgical difficulty for both upper and lower jaw teeth removal. However, for this analysis, only complications related to extractions in the maxilla were considered [3]. Fracture of root tips was also classified as the second most common complication, while OAC was reported only in one patient [3]. A total of 39 OAC and 41 root fractures were reported, making these two complications the most common ones. However, it is impossible to conclude from these studies which one is exactly the most common because of insufficient data. Table 3 summarizes the findings.

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Table 4. The most common complications diagnosed in the mandible.

Author AO IAN sensation disorder LN sensation disorder Pain Root fractures Delayed healing Sigron et al. [1] n=50 n=15 n=3 - - - Contar et al. [3] n=2 n=6 n=1 n=26 n=16 - Osunde et al. [4] n=9 n=2 n=1 - - n=19

AO = alveolar osteitis; IAN = inferior alveolar nerve; LN = lingual nerve.

Complications in the lower jaw were reported in three out of four selected articles [1,3,4]. These articles extracted three common complications: AO and sensation disorders due to the IAN and LN. However, all the articles reported different complications as the most common ones. AO [1], pain [3] and delayed healing were reported by the last paper [4]. It is possible to conclude that AO (n=61) and sensation disorders (n=28) are the most frequent since they were reported in all clinical trials. Temporary paresthesia occurred more often than permanent. Sigron et al. [1] reported 12 cases of temporary and 6 cases of permanent sensation disturbances. Contar et al. [3] reported that all cases were temporary, while no description was given by Osunde et al. [4]. Contar et al. [3] and Osunde et al. [4] also demonstrated that fully impacted teeth increase the possibility of nerve damage. Details are presented in Table 4.

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3. DISCUSSION

The present literature review’s objective was to test the hypothesis of whether more complications during wisdom teeth extraction appear in the maxilla or the mandible. Four retrospective studies that satisfied the inclusion criteria were included in the review [1-4]. All of them were assessed as good quality studies and were included in the systematic review.

As one of the most common procedures performed by oral surgeons in daily practice, the extraction of third molars requires good knowledge of the upper and lower jaw anatomy and operator experience to minimize the risk of complications [9,15,16,19]. Several indications are presented in the literature to remove either impacted or erupted wisdom teeth [12,17,20,21]. According to the NIH [21], teeth diagnosed with follicular enlargement, pericoronitis, very deep caries that are impossible to treat, and third molars that destroy the distal side of the second molar or cause bone destruction should be removed. Sayed et al. [9], in the result of a study, demonstrated that intra or postoperative complications associated with third molar extractions occurred more in the mandible than in the maxilla. Pourmand et al. [2] mentioned the same findings. This data matches the results of this review, which presents a total of 182 complications out of 2.392 extractions that occurred in the mandible, compared with 112 complications out of 2.398 wisdom teeth extracted from the maxilla.

This can be explained by the specific anatomy of the mandible in relation to wisdom teeth location. Mandibular third molars are situated in the region of the weakness of the mandible, where the thinnest part of the ramus meets the distal end of the body of the mandible. This increases the risk of mandibular fracture during the removal, especially of impacted third molars. Another factor is the position of the roots of these teeth in relation to MC. The roots are often in very close proximity or even pass through the MC, which causes damage to the branches of the trigeminal nerve during extraction, subsequently causing temporary or permanent sensory disturbances [12,15]. An example is provided in Figure 1.

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Fig. 1. An example of the superimposition of tooth number 38 and tooth number 48 roots on the MC can be observed in this OPG. In such a case, there is a high probability of an IAN injury during extraction.

Temporary paresthesia is considered when the normal sensation is restored in the following six months, while a loss of sensation of more than six months post-surgically is considered permanent [15]. The complication rates are also associated with whether the teeth are impacted or erupted. The depth of impaction plays a crucial role in third molar surgery and can predict the manifestations of complications [8,12]. Juodzbalys and Daugela [12] presented a new classification regarding mandibular third molars impaction and removal difficulty based on anatomical and radiological peculiarities. This classification is presented in Annex 2.

This review also analyzed complications related to the IAN and LN paresthesia [1,3,4]. As presented in Table 4, there is a higher number of complications related to the IAN (n=23) than to LN (n= 5). However, the literature offers different data than in the present review. Sayed et al. [9], in the result of a retrospective study, presented a rate of injury of LN of 5.6% compared to 1.6% for IAN. In the literature, the higher amount of nerve damage was also associated with LN damage [8,12]. Jerjes et al. [16], in the result of a prospective study performed on 1.087 patients, agrees with the literature that LN is more affected than IAN during the extraction of third molars. In this review, the incidence of temporary paresthesia occurred more often than permanent, and it matches the evidence from the literature [9,23]. It was not possible to conclude if either males or females are more affected by paresthesia.

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25 Radiological examinations such as OPG are all the time required before a third molar surgery. However, in some cases, this method cannot provide sufficient diagnostic accuracy due to magnifications and distortion, so additional, more detailed X-rays such as CBCT or computed tomography (CT) are required. CBCT is the most accurate radiographic method for determining the precise location of the third molar roots and the surrounding structures, most importantly MC in the lower jaw or maxillary sinus in the upper jaw [2,8,10,27]. An example is provided in Figure 2.

Fig. 2. Example of impacted wisdom tooth number 18 that is located very deep in the maxillary bone. The counterpart, tooth number 28, is impacted as well but does not represent a deep impaction as tooth number 18. In this case, the operator has to be attentive because there is a very high possibility that the extraction of tooth number 18 leads to OAC or tooth displacement into the maxillary antrum. In the lower jaw, the superimposition of the roots of tooth number 48 on the MC can be observed.

In the study by Sigron et al. [1], the wisdom teeth were classified according to the OPG in seven impaction classes, and further according to the position of third molars on the MC in 5 classes (none, at the superior border, half, complete, beyond the inferior border). Out of 1.085 molars that presented a radiological position on the MC, 120 were entirely projected on the MC, and 179 were projected over half of the MC, and 44 had the root apices beyond the inferior border of the MC. They demonstrated that the occurrence of sensation disorders is significantly higher (p<0.0001) when the roots of third molars are positioned on the inferior border of the MC. Details are presented in Annex 3. Similar findings are

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reported by Contar et al. [3], where mandibular third molars are divided into three categories according to the level of surgical difficulty: third molars requiring only forceps, third molars requiring osteotomy and third molars that need osteotomy and tooth sectioning. During the extraction of 1.699 maxillary and mandibular teeth, 59 complications occurred, from which 53 were reported in the mandible, and most of them occurred in impacted third molars that require osteotomy and tooth sectioning (n=31).

Osunde et al. [4] studied only impacted mandibular molars, so the surgical difficulty was similar to the second and third categories presented by Contar et al. [3]. The authors did not present data about the impaction degree or the position of the MC to the impacted third molars, but they reported that the mesioangular (n=176) and distoangular (n=73) impactions were the most common types of impaction, matching the data from Sigron et al. [1], of impacted tooth tipped mesially (192) and distally (74). Similar data is presented by Juodzbalys and Daugela [12], where distoangular and horizontal impaction is most likely to cause complications. It cannot be concluded if either mesioangular, distoangular or horizontal position mostly leads to complications, but the literature reports a high incidence rate associated with any of them. Picture 3 shows an example of a horizontal impaction.

Fig. 3. Example of horizontal impaction of tooth number48. It represents a high risk of iatrogenic trauma to the adjacent tooth number 47. In this X-ray, it is impossible to visualize the relation to the MC, and therefore it cannot be concluded if possible sensory damage can occur.

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27 These studies’ result proves a definite relationship between the depth of impaction of third molars and the IAN or LN damage risk. Another evident thing is that projection of third molar roots on the MC will highly increase the risk of nerve damage. This data is matching the literature [7-9,12,19].

AOwas reported as a frequent complication in the mandible. However, it can also appear in the maxilla [1,3,4,7,9]. AO or dry socket is a common postoperative complication characterized by severe pain in and around the extraction socket that develops 1 to 3 days after surgery [24,28]. In this review, AO had the highest number of complications associated with mandibular third molar surgery compared to other complications that occurred. The pain reported by Contar et al. [3] made up also a significant amount; however, it was not associated with AO but with bad oral hygiene, food impaction and trauma from sutures. Besides the fact that the study was based on extraction on both jaws, all the pain cases occurred only in the mandible [3]. This review corresponds with the literature regarding the frequency of AO, but there is a lack of information on whether it occurs more in the mandible or maxilla [3-5,7,24].

Nonetheless, in Kolokythas et al. [28], it is stated that during the mandibular third molar extractions, AO development’s risk varies between 1% to 37.5%. Sigron et al. [1], in the result of the study, determined that AO affected more females than males and was associated with previous pericoronitis. These findings correspond with the literature [13,19]. Besides, AO has a higher risk of developing in older patients [4,9]. Pain, root fractures and delayed wound healing were mentioned by two articles and proved to appear in high numbers in these studies. However, they are not mentioned as most common in the literature. Less common complications reported by literature in the lower jaw are trismus, mandibular fractures, abscesses, wound dehiscence, sequestra formation, and displacement of mandibular third molars into sublingual, submandibular, infratemporal or pterygomandibular spaces [1,3,7,13,24]. The incisions and suturing techniques appear to be essential in preventing post-surgical complications of impacted mandibular wisdom teeth [5,6].

In this review, two articles evaluated complications associated with the upper jaw [2,3]. As mentioned in Table 3, OAC and root fractures are the most common complications that were observed. The maxillary sinus location in proximity to the posterior teeth increases the risk of OAC during surgery. Root fractures are also associated with OAC, and it increases the risk of perforation from 12% to 27% because the applied force is increased to extract the fractured roots [2,7,25,26].

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In the paper by Pourmand et al. [2], from 1.562 extracted third molars, 106 complications occurred, from which 38 were OAC, while in the study of Contar et al. [3], only 1 case was reported. Nonetheless, this number is due to a mixed study that included extractions in both arches, and it was not based only on the maxilla, therefore reducing the number of OAC.

In the study by Santamaria et al. [25], after the removal of 389 maxillary third molars, 20 OAC were reported. Also, the possibility of sinus perforation highly increased with the depth of impaction and level of difficulty of extraction. This recognition is similar to Pourmand et al. [2] data, where type 5 of impaction presented the perforation risk. Annex 4 represents the prevalence of OAC concerning retention type. In another study by Rothamel et al. [26], 1.057 extractions were performed, but 134 were already related to the perforated maxillary sinus, 88 out of 370 resulted in acute OAC and these molars were impacted. Partially impacted molars created 23 out of 222 perforations and fully erupted only 23 of 465, and these differences are significant.

Less common complications associated with third molars extraction in the upper jaw are fracture of the maxillary tuberosity, displacement of tooth or tooth fragments into the maxillary sinus or infratemporal fossa and injury of buccal fat pad [2,7,13,24]. In the result of this review and comparison to the available literature, it can be stated that indeed OAC and root fracture, or a combination of these both, are the most common local complications occurring in the maxilla.

Complications that can occur in both jaws are iatrogenic injury to the adjacent teeth, AO, pain, bleeding, postoperative swelling and infection, injury of adjacent soft tissues (tongue, lips), breakage of surgical instruments [7,13,24].

The hypothesis set at the begging of the review was answered, and more complications occur in the mandible than the maxilla.

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4. CONCLUSIONS

Within the limitations of the present study, it can be concluded:

1. The risk of complication is increased in the case of impacted teeth compared to erupted ones. 2. The level of impaction is an essential factor of the third molar extraction in the lower jaw. The

depth of impaction highly increases the risk of IAN and LN damage.

3. Patients undergoing third molar surgery after 30 years of age are at higher risk to be affected by post-surgical morbidity and complications.

4. The most common local complications occurring in the upper jaw resulting from wisdom teeth extractions are oroantral communication and root fractures. In the lower jaw, alveolar osteitis, injury to inferior alveolar and lingual nerves, pain, root fractures, and delayed wound healing are mostly recorded.

5. ACKNOWLEDGEMENT

I would like to deeply thank my supervisor, Professor Gintaras Juodžbalys, whose expertise was invaluable. Your feedback pushed me to sharpen my thinking and brought my work to a higher level.

6. CONFLICT OF INTEREST

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7. PRACTICAL RECOMMENDATIONS

Every case is very individual, and anatomical structures vary significantly from one person to another. That is why OPG or CT must always accompany wisdom teeth extraction for sound knowledge and understanding of anatomy and, therefore, decrease the risk of complications. This review also emphasizes the importance of radiological examination in third molar surgery. In case of local complications during or after the extraction, oral surgeons must be well aware and prepared to manage the case in the best possible way.

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9. ANNEXES

Annex 1. Protocol for systematic review according to PRISMA [30].

Title LOCAL COMPLICATIONS OF WISDOM TEETH REMOVAL:

A LITERATURE REVIEW Introduction

Aim This review aims to assess all the possible local complications associated with wisdom teeth surgery and to understand which factors contribute to the appearance of the complications. Tasks 1. To find out the most commonly occurring complications,

particularly for the upper and lower jaw.

2. To evaluate if there is a connection between the level of impaction and the complication risk.

3. To discover if increased age leads to a higher risk of having complications.

4. To determine whether the complication rate is higher in impacted wisdom teeth removal compared to erupted ones. Methods

Eligibility criteria PICO:

• P- patients: patients in need of either erupted or impacted wisdom teeth removal

• I- intervention: simple or surgical extraction

• C- comparison: complication rate between the maxilla and mandible

• O- outcome: severity of complications associated with the difficulty degree of surgical intervention

Inclusion criteria:

-Clinical trials with more than 50 wisdom teeth extractions. -Studies published in the English language.

-Studies that focus on the complications that appear intra and postoperatively, but not only on the management and prevention. -Studies on patients that require third molar extractions, including impacted and non-impacted third molar cases.

-Extraction of third molars due to various reasons, including caries, cysts, benign or malignant tumours, impaction and orthodontic reasons.

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35 -Studies on animals.

-Case reports.

-Studies that focus on extraction complications on teeth other than third molars.

-Extra or intraoral trauma as an extraction cause.

-Patients with severe and uncontrolled systemic disorders such as diabetes mellitus, cardiovascular disorders and blood coagulation disorders.

Information sources -Electronic databases: PubMed, Cochrane Library

-Keywords: postoperative complications; tooth, impacted; tooth extraction; Surgical Flaps; molar, third; Retrospective Studies -Time period: January 2010 – November 2020

Study selection -The keywords used to conduct the literature search were used in various combination and according to inclusion criteria.

-Screening with exclusion of duplicates. -Eligibility according to exclusion criteria.

-Only articles that meet the set criteria were included.

Outcomes and prioritization To analyse the outcomes of wisdom teeth extractions and the following local complications in dependence on the case’s surgical severity.

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Annex 3. Represents the prevalence of IAN paraesthesia in relation to the third molar root position [1].

LOCAL COMPLICATIONS OF WISDOM TEETH EXTRACTIONS: A LITERATURE REVIEW

Loran Omer