Prevalence and Patterns of Impacted Maxillary third Molar in a Private Dental Institution
Nor Masitah Mohamed Shukri1, Santhosh Kumar MP2*, Arthi Balasubramaniam3
1 Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai 600077, Tamil Nadu, India.
2 Reader, Department of Oral and Maxillofacial Surgery, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai 600077, Tamil Nadu, India.
3 Senior Lecturer, Department of Public Health Dentistry, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai 600077, Tamil Nadu, India.
*Corresponding Author
Santhosh Kumar MP,
Reader, Department of Oral and Maxillofacial Surgery, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Saveetha University, 162, PH
Road, Chennai 600077, Tamil Nadu, India.
Tel: +918903271734
E-mail: santhoshkumar@saveetha.com
Received: May 16, 2021; Accepted: August 5, 2021; Published: August 17, 2021
Citation:Nor Masitah Mohamed Shukri, Santhosh Kumar MP, Arthi Balasubramaniam. Prevalence and Patterns of Impacted Maxillary third Molar in a Private Dental Institution. Int J Dentistry Oral Sci. 2021;8(8):3820-3826. doi: dx.doi.org/10.19070/2377-8075-21000783
Copyright: Santhosh Kumar MP©2021. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.
Abstract
Tooth impaction can be defined as that failure of the tooth to erupt into its normal physiological position and oftentimes, it is associated with a third molar. Third molar is also known as wisdom tooth, meaning it is the last tooth to erupt into the oral cavity even in the age of adolescent or adulthood. Although third molar impaction remains indefinitely asymptomatic, some individuals may be presented with tenderness and swollen gums. Impacted teeth are commonly treated with tooth removal. Conservative approach is recommended in asymptomatic cases and when the risks of the procedure outweigh the expected benefit. The aim of this study was to investigate the prevalence and pattern of maxillary third molar impaction, angulation and level of eruption among patients treated in Saveetha Dental College. Data collection was done in a university setting. Data regarding patients having impacted teeth were retrieved after analyzing 86000 case sheets. The following parameters were evaluated based on the dental records; age, gender, level of eruption and angulation pattern. Radiographs and intraoral photographs were used to assess the patterns of maxillary third molar impaction. Excel tabulation and SPSS version 23 was used for data analysis. The statistical test used for the demographics was frequency, percentage and for tests of association between categorical variables was Chi-square test. P value less than 0.05 was considered as statistically significant. Women had more prevalence (58.5%) of impaction than men and was seen most in the age group of 21-40 years. 64.6% and 35.4% of the total teeth were 18 and 28, respectively. The most common angulation of impaction in maxilla was vertical (55.4%). Position C impaction had greater occurrence (61.5%) compared to other two levels of impaction. No significant difference was found between right and left sides in maxilla, (p=0.447). There was no significance of angulation and level of impaction with respect to age and gender. Within the limits of the study, impacted maxillary third molars were more prevalent in female and younger patients. Vertical angulation and level C position were more frequently seen in impacted maxillary third molars.
2.Introduction
3.Conclusion
4.References
Keywords
Angulation; Impaction; Maxillary Third Molar; Prevalence; Pattern; Position.
Introduction
A tooth becomes impacted when it is pathologically unable to
erupt or develop into its normal functional position. Third molars
are the most frequently impacted of all teeth, precisely mandibular
third molars [46]. Impacted maxillary third molars occur
frequently in people followed by mandibular third molars and
may require surgical removal for several reasons. Nevertheless,
the occurrence of impacted third molars vary according to the
populations and was reported to range from 18% to 70%. Racial
variations in the regards of facial development, jaw and teeth size
are the important attributes for the process of teeth eruption [9].
Third molars impaction has been related with some pathological
changes. For instance, root resorption, pericoronitis, periodontal
disease, neoplasms and damage to the adjacent teeth [2]. A study
by Meisami et al had reported a weakened angle of mandible that
is prone to fracture due to the third molar impaction [28]. Che et al found periodontal loss more than 5 mm of second molar next
to the impacted mandibular third molar. Also, 7% of the 2115
subjects were diagnosed with dental caries in their second molars
in Chinese population [8]. Impaction can be attributed to the
trauma, pathologies and insufficient space in the jaw, leading to
pain, swollen gums, infections, dental caries and cyst formation.
Impacted maxillary third molars can cause several complications
if they are in close proximity to the surrounding anatomic structures
like maxillary sinus. On the other hand, impacted teeth can
also be classified due to systemic and local factors [26]. Systemic
factors that possibly can affect the pattern of tooth eruption are
cleidocranial dysplasia, Down syndrome, endocrine deficiencies,
febrile disease and irradiation [6]. Retained deciduous teeth, malposed
tooth germs, supernumerary teeth, odontogenic tumors
and cleft lip and palate are the common local factors that might
influence teeth impaction [17, 37, 29].
Multiple classification systems have existed to describe the third
molar impactions in the terms of angulation of the impaction,
level and depth of the impaction and the relation to the anterior
border of ascending ramus of mandible. These classifications
help in developing optimal treatment plans in regard to the difficulty
of the surgical extraction and reduce associated complications
during surgery. In the Pell & Gregory classification system,
impacted teeth are determined based on their level of eruption
in relation to the occlusal surface of the second molar vertically,
dental longitudinal axis and relationship to the anterior border of
the ascending ramus of mandible [36].
Winters classified impactions based on the angulation of the
third molar to the longitudinal axis of the second molar. The
system consists of mesioangular, distoangular, vertical and horizontal
[54]. Orthopantomography (OPG) is considered as the
best choice technique of evaluating dental pathologies, especially
dental impaction. The level of impaction, angulation of impaction,
amount of bone covered in impacted teeth and proximity
between third molar and inferior alveolar nerve can be easily assessed
with OPG [36].
Dentists diagnose patients’ teeth, gums and other related parts
of the mouth. They are responsible for giving advice in terms of
oral hygiene care and diet choice that affect oral health. Among
these, orthodontists are obligated to treat malalignments of the
teeth. Therefore, early assessment of a third molar eruption in
young growing patients will definitely be helpful for the treatment
outcome.
According to most orthodontists, consideration of mandibular
and maxillary third molar impaction are really important in preventing
relapse in the lower anterior region, molar distalization,
pericoronitis, dental caries prevalence and arch crowding. Castella
et al stated that third molar impaction was an estimated event seen
in extraction and nonextraction patients. Oftentimes, agenesis of
third molars happens in the order of two, one, three and all the
four third molars [19].
Considering the rarity of retrospective studies investigating the
pattern of maxillary third molar impaction in the southeast area
of India, this study was aimed to investigate the prevalence and
patterns of maxillary third molar impaction among dental patients
treated in Saveetha Dental College. Previously our team has
a rich experience in working on various research projects across
multiple disciplines [18], [50], [4], [30], [20], [10], [12], [32], [39],
[14], [53], [33], [31], [45]. Now the growing trend in this area motivated
us to pursue this project. The objectives were to determine
the relationship between the angulation and level of impaction
with different age groups and gender.
Materials and Methods
Study design and study setting
This retrospective study was conducted in Saveetha Dental College
and Hospital, Saveetha University, Chennai, to evaluate
the prevalence and patterns of impacted maxillary third molars
among patients reporting from June 2019 to March 2020. The approval
for this university setting study was obtained from the institutional
review board and it was covered by the ethical approval
number; SDC/SIHEC/2020/DIASDATA/0619-0320.
Study population and sampling
Inclusion criteria for the study were patients at least 18 years of
age, with complete root formation of third molars, and no history
of third molar extraction. Patients with dental pathologies,
malalignment in the occlusal plane and presence of congenital
diseases or facial syndromes were excluded from this study. After
assessment in the university patient data registry, case records
of 65 patients who were diagnosed with impacted maxillary third
molars and were eligible for the study were included in the study.
Cross verification of data for errors was done with the help of an
external examiner.
Data collection
Data regarding patients having impacted teeth were retrieved after
analyzing 86000 case sheets. Radiographs and intraoral photographs
of patients having impaction were reviewed. The following
criteria were examined based on the dental records: age, sex,
level of eruption and angulation pattern of impacted maxillary
third molars. All the radiographs collected were assessed for the
following parameters: number of the impacted maxillary third
molars, angulation of the impaction and level of the impaction.
Maxillary third molar is considered impacted when it was not fully
erupted into the normal functional location in the occlusal plane
or the lowest portion of the impacted tooth was below the occlusal
plane of the second molar. Winter’s classification was used
to determine the angulation pattern of the impacted maxillary
third molars. The following classification system adopted were ;
0°-10°, vertical; 11°-79°, mesioangular or distoangular; 80°-100°,
horizontal, and the remaining cases were classified as cases of
inverted or buccolingual impaction.
The level of impaction was recorded using Pell and Gregory classification;
Position A, the highest portion of the impacted tooth
was on same level of above the occlusal plane / not buried in
bone; Position B, the highest portion of the impacted tooth was
below the occlusal plane but above the cervical line of second
molar; Position C, the highest portion of the impacted tooth was
below the cervical line of second molar / completely buried in
bone. All the data collected were tabulated in MS Excel and incomplete
data was eliminated.
Statistical Analysis
The collected data was validated, tabulated and analysed with
Statistical Package for Social Sciences for Windows, version 23.0
(SPSS Inc., Chicago, IL, USA) and results were obtained. Categorical
variables were expressed in frequency and percentage; and
continuous variables in mean and standard deviation. Chi-square
test was used to test associations between categorical variables. P
value < 0.05 was considered statistically significant.
Results & Discussion
In our study, we evaluated the incidence of impacted maxillary
third molars among the patients treated in our college and its association
with gender and age groups. We observed that women
had higher prevalence (58.5%) of impaction than men [Figure 1]
and were seen mostly in the age group of 21-40 years. [Figure 2].
64.6% and 35.4% of the total teeth were 18 and 28, respectively.
[Figure 3]. Level C impaction had greater occurrence (61.5%)
compared to other two levels of impaction. [Figure 4]. The most
common angulation of impaction in maxilla was vertical (55.4%). [Figure 5]. No statistically significant association was found between
angulation and level of impaction with respect to age and
gender.
The prevalence of maxillary third molar impaction found from
this study was lower, in corroborating with a study by Reddy et al
done in Indians (27%). However, the current studies by Quek et
al and Hassan et al reported higher frequencies done in Singaporean
Chinese (68.6%) and Saudi Arabians (40.5%), respectively.
Hassan stated that the most common number of impactions per
patient was one and Quek found that two was the highest frequency
number of impacted third molars per patient. Conversely,
the findings of Ma’aita et al reported that Jordanian patients had
impaction of all four third molars. Different racial populations
nationwide can influence these variations of consensus[1].
In our study, females had a higher proportion of impaction compared
to males. This is consistent with previous study that stated
higher frequency of the impaction was observed in women. Similarly,
Heshemipour et al reported that females were more frequently
observed in the association of impacted maxillary third
molars [3]. These findings are in accordance with the results of
previous studies [16, 21, 25]. The significant difference between
gender can be attributed to the rate of growth and development
of mandibles. There is evidence of females having less incremental
growth and reduced time taken for mandibles to fully grow
than males. Third molars begin to erupt when growth in females
stops, whereas, the growth of the jaws still continues in males,
considering more space created for the eruption of third molars
[24].
In our study, more than half of the patients were in the range
of 21 to 40 years old. It was observed that the prevalence of
impacted maxillary third molars declines with the increasing age.
In recent study, results showed younger subjects had more prevalence
of rate of impaction [5]. This is correlated with the findings
of Hashemipour et al in which half of the patients were in the
third decade of their lives [3]. Besides, Garcia and Chauncey [13,
5, 42, 48] and Reddy reported high prevalence of impacted third
molars among the young-aged population. However, there is also
previous literature showing increased prevalence of impaction in
older patients, above 40 years. Lack of awareness among these
patients may have delayed the treatment of impaction [3].
Radiological examination revealed vertical impaction was the first
common in this study (55.4%). This is in accordance with many
other studies where the frequency of vertical impaction ranged
from 14.1%-49.6% [5, 15]. According to a study of Saudi population,
vertical angulation was the most frequent angulation seen
in both maxillary and mandibular arch. In the maxilla, 44.1% of
the study population had vertical angulation of impacted third
molars followed by 37.1% distoangular impaction [5]. Reddy et
al also found that the most common angulation of impaction in
maxilla was vertical [(Reddy KVG, no date)]. However, Kruger et
al reported that mesioangular impaction was the most common
angulation impaction in the maxillary arch [23]. Some opposing
studies revealed mesioangular impaction as the commonest [1].
The possible reason for different findings can be related to the
fact of various methods used to classify angulation of impaction
in each study. As it is solely based on visual impression, the reliable
comparison of reported impaction was challenging.
The C level (61.5%) was the commonest level of impaction in
our study. In line with the current study, Bayoumi et al and Alfadil
at al observed that the C level impactions were the most
commonly seen maxillary third molars impaction. Quek et al also
reported the highest proportion of the C level impactions in maxilla
than in the mandible, which was statistically significant [3, 28].
Contrary to this, the most common levels of impaction in their
studies were B level [15] and A level [1]. There was no statistical
significant association in the angulation pattern of third molar
impaction between males and females in our study. This is supported
with some investigations done by Sandhu and Kaur, Montelius,
Topkara A and Hattab et al., [49]. However, some other
prevalence studies reported a significantly greater frequency of
third molar impaction [3]. Differences of the findings were possibly
due to the limited data availability, ethnic variations, genetic
hereditary and jaw-tooth size. Our institution is passionate about
high quality evidence based research and has excelled in various
fields [34, 40, 52, 11, 38, 47, 51, 7, 27, 43, 44]. We hope this study
adds to this rich legacy.
As the current study was hospital-based, it may lack randomization
which is the limitation of the study. Further studies should
be conducted to evaluate the possible etiologies behind the prevalence
of impaction in other regions of Tamil Nadu.
Figure 1. The herbal mouthwash mediated zone of inhibition against the evaluated pathogens inoculated into 5mm wells.
Figure 2. The herbal mouthwash mediated zone of inhibition against the evaluated pathogens inoculated into 5mm wells.
Figure 3. The graphical representation of herbal mouthwash mediated zone of inhibition against the evaluated pathogens inoculated into 5mm wells.
Figure 4. The graphical representation of Herbal mouthwash mediated Cytotoxicity using Brine Shrimp Lethality Assay.
Figure 5. The herbal mouthwash mediated zone of inhibition against the evaluated pathogens inoculated into 5mm wells.
Figure 6. The graphical representation of herbal mouthwash mediated zone of inhibition against the evaluated pathogens inoculated into 5mm wells.
Figure 7. The graphical representation of Herbal mouthwash mediated Cytotoxicity using Brine Shrimp Lethality Assay.
Figure 8. The herbal mouthwash mediated zone of inhibition against the evaluated pathogens inoculated into 5mm wells.
Figure 9. The graphical representation of herbal mouthwash mediated zone of inhibition against the evaluated pathogens inoculated into 5mm wells.
Figure 10. The graphical representation of Herbal mouthwash mediated Cytotoxicity using Brine Shrimp Lethality Assay.
Figure 10. The herbal mouthwash mediated zone of inhibition against the evaluated pathogens inoculated into 5mm wells.
Figure 11. The graphical representation of herbal mouthwash mediated zone of inhibition against the evaluated pathogens inoculated into 5mm wells.
Conclusion
Within the limits of this Study it can be concluded that, there is
high prevalence of gingivitis among pediatric patients, however,
there is no significant association between age, gender and severity
of gingivitis.
References
-
[1]. Paster BJ, Boches SK, Galvin JL, Ericson RE, Lau CN, Levanos VA, et al. Bacterial diversity in human subgingival plaque. J Bacteriol. 2001
Jun;183(12):3770-83.Pubmed PMID: 11371542.
[2]. Park OJ, Yi H, Jeon JH, Kang SS, Koo KT, Kum KY, et al. Pyrosequencing Analysis of Subgingival Microbiota in Distinct Periodontal Conditions. J Dent Res. 2015 Jul;94(7):921-7.Pubmed PMID: 25904141.
[3]. Pérez-Chaparro PJ, Gonçalves C, Figueiredo LC, Faveri M, Lobão E, Tamashiro N, et al. Newly identified pathogens associated with periodontitis: a systematic review. J Dent Res. 2014 Sep;93(9):846-58.Pubmed PMID: 25074492.
[4]. Socransky SS, Haffajee AD, Cugini MA, Smith C, Kent RL Jr. Microbial complexes in subgingival plaque. J Clin Periodontol. 1998 Feb;25(2):134- 44.Pubmed PMID: 9495612.
[5]. Hajishengallis G, Lamont RJ. Beyond the red complex and into more complexity: the polymicrobial synergy and dysbiosis (PSD) model of periodontal disease etiology. Mol Oral Microbiol. 2012 Dec;27(6):409-19.Pubmed PMID: 23134607.
[6]. Nakazawa F, Poco SE, Ikeda T, Sato M, Kalfas S, Sundqvist G, et al. Cryptobacterium curtum gen. nov., sp. nov., a new genus of gram-positive anaerobic rod isolated from human oral cavities. Int J Syst Bacteriol. 1999 Jul;49 Pt 3:1193-200.Pubmed PMID: 10425779.
[7]. Kumar PS, Griffen AL, Barton JA, Paster BJ, Moeschberger ML, Leys EJ. New bacterial species associated with chronic p
eriodontitis. J Dent Res. 2003 May;82(5):338-44.Pubmed PMID: 12709498. [8]. Lopez-Oliva I, Paropkari AD, Saraswat S, Serban S, Yonel Z, Sharma P, et al. Dysbiotic Subgingival Microbial Communities in Periodontally Healthy Patients With Rheumatoid Arthritis. Arthritis Rheumatol. 2018 Jul;70(7):1008-1013.Pubmed PMID: 29513935.
[9]. Kim KS, Rowlinson MC, Bennion R, Liu C, Talan D, Summanen P, et al. Characterization of Slackia exigua isolated from human wound infections, including abscesses of intestinal origin. J Clin Microbiol. 2010 Apr;48(4):1070-5.Pubmed PMID: 20107092.
[10]. Wade WG, Downes J, Dymock D, Hiom SJ, Weightman AJ, Dewhirst FE, et al. The family Coriobacteriaceae: reclassification of Eubacterium exiguum (Poco et al. 1996) and Peptostreptococcus heliotrinreducens (Lanigan 1976) as Slackia exigua gen. nov., comb. nov. and Slackia heliotrinireducens gen. nov., comb. nov., and Eubacterium lentum (Prevot 1938) as Eggerthella lenta gen. nov., comb. nov. Int J Syst Bacteriol. 1999 Apr;49 Pt 2:595-600. Pubmed PMID: 10319481.
[11]. Poco SE Jr, Nakazawa F, Ikeda T, Sato M, Sato T, Hoshino E. Eubacterium exiguum sp. nov., isolated from human oral lesions. Int J Syst Bacteriol. 1996 Oct;46(4):1120-4.Pubmed PMID: 8863445.
[12]. Smith AJ, Wade WG. Serum antibody response against oral Eubacterium species in periodontal disease. J Periodontal Res. 1999 Apr;34(3):175-8.Pubmed PMID: 10384406.
[13]. Booth V, Downes J, Van den Berg J, Wade WG. Gram-positive anaerobic bacilli in human periodontal disease. J Periodontal Res. 2004 Aug;39(4):213- 20. PubmedPMID: 15206913. [14]. Tran T, Flynn MJ, Chen C, Slots J. Porphyromonas endodontalis in subgingival plaque. Clin Infect Dis. 1997 Sep;25 Suppl 2:S222-3.Pubmed PMID: 9310685.
[15]. Lombardo Bedran TB, Marcantonio RA, Spin Neto R, Alves Mayer MP, Grenier D, Spolidorio LC, et al. Porphyromonas endodontalis in chronic periodontitis: a clinical and microbiological cross-sectional study. J Oral Microbiol. 2012;4.Pubmed PMID: 22232719.
[16]. Downes J, Munson MA, Radford DR, Spratt DA, Wade WG. Shuttleworthia satelles gen. nov., sp. nov., isolated from the human oral cavity. Int J Syst Evol Microbiol. 2002 Sep;52(Pt 5):1469-1475.Pubmed PMID: 12361248.
[17]. Colombo AP, Boches SK, Cotton SL, Goodson JM, Kent R, Haffajee AD, et al. Comparisons of subgingival microbial profiles of refractory periodontitis, severe periodontitis, and periodontal health using the human oral microbe identification microarray. J Periodontol. 2009 Sep;80(9):1421-32.Pubmed PMID: 19722792. https://pubmed.ncbi.nlm.nih.gov/19722792/
[18]. Hill GB, Ayers OM, Kohan AP. Characteristics and sites of infection of Eubacterium nodatum, Eubacterium timidum, Eubacterium brachy, and other asaccharolytic eubacteria. J Clin Microbiol. 1987 Aug;25(8):1540-5.Pubmed PMID: 3624445. https://pubmed.ncbi.nlm.nih.gov/3624445/
[19]. Booth V, Downes J, Van den Berg J, Wade WG. Gram-positive anaerobic bacilli in human periodontal disease. J Periodontal Res. 2004 Aug;39(4):213-20.Pubmed PMID: 15206913. https://pubmed.ncbi.nlm. nih.gov/15206913/
[20]. Wade WG. The role of Eubacterium species in periodontal disease and other oral infections. Microb. ecol. health dis. 1996 Jan 1;9(6):367-70.
[21]. Uematsu H, Hoshino E. Predominant obligate anaerobes in human periodontal pockets. J Periodontal Res. 1992 Jan;27(1):15-9.Pubmed PMID: 1531505.
[22]. Kumar PS, Griffen AL, Moeschberger ML, Leys EJ. Identification of candidate periodontal pathogens and beneficial species by quantitative 16S clonal analysis. J Clin Microbiol. 2005 Aug;43(8):3944-55.Pubmed PMID: 16081935.
[23]. Cato EP, MOORE LV, Moore WE. Fusobacterium alocis sp. nov. and Fusobacterium sulci sp. nov. from the human gingival sulcus. Int J Syst Evol Microbiol. 1985 Oct 1;35(4):475-7.
[24]. Griffen AL, Beall CJ, Campbell JH, Firestone ND, Kumar PS, Yang ZK, et al. Distinct and complex bacterial profiles in human periodontitis and health revealed by 16S pyrosequencing. ISME J. 2012 Jun;6(6):1176-85.Pubmed PMID: 22170420.
[25]. Aruni AW, Roy F, Fletcher HM. Filifactor alocis has virulence attributes that can enhance its persistence under oxidative stress conditions and mediate invasion of epithelial cells by porphyromonas gingivalis. Infect Immun. 2011 Oct;79(10):3872-86.Pubmed PMID: 21825062.
[26]. Aruni AW, Mishra A, Dou Y, Chioma O, Hamilton BN, Fletcher HM. Filifactor alocis--a new emerging periodontal pathogen. Microbes Infect. 2015 Jul;17(7):517-30.Pubmed PMID: 25841800.
[27]. Schlafer S, Riep B, Griffen AL, Petrich A, Hübner J, Berning M, et al. Filifactor alocis--involvement in periodontal biofilms. BMC Microbiol. 2010 Mar 1;10(1):66.Pubmed PMID: 20193074.
[28]. Wang Q, Jotwani R, Le J, Krauss JL, Potempa J, Coventry SC, et al. Filifactor alocis infection and inflammatory responses in the mouse subcutaneous chamber model. Infect Immun. 2014 Mar;82(3):1205-12.Pubmed PMID: 24379289.
[29]. Nokhbehsaim M, Nogueira AV, Damanaki A, Dalagiorgou G, Eick S, Adamopoulos C, et al. Regulation of matrix metalloproteinase-1 by Filifactor alocis in human gingival and monocytic cells. Clin. Oral Investig.2019 Aug 23:1-9.
[30]. Armstrong CL, Klaes CK, Vashishta A, Lamont RJ, Uriarte SM. Filifactor alocis manipulates human neutrophils affecting their ability to release neutrophil extracellular traps induced by PMA. Innate Immun. 2018 May;24(4):210-220.Pubmed PMID: 29649915.
[31]. Moffatt CE, Whitmore SE, Griffen AL, Leys EJ, Lamont RJ. Filifactor alocis interactions with gingival epithelial cells. Mol Oral Microbiol. 2011 Dec;26(6):365-73.Pubmed PMID: 22053964.
[32]. Aruni AW, Zhang K, Dou Y, Fletcher H. Proteome analysis of coinfection of epithelial cells with Filifactor alocis and Porphyromonas gingivalis shows modulation of pathogen and host regulatory pathways. Infect Immun. 2014 Aug;82(8):3261-74.Pubmed PMID: 24866790.
[33]. Aruni AW, Zhang K, Dou Y, Fletcher H. Proteome analysis of coinfection of epithelial cells with Filifactor alocis and Porphyromonas gingivalis shows modulation of pathogen and host regulatory pathways. Infect Immun. 2014 Aug;82(8):3261-74.Pubmed PMID: 24866790.
[34]. Olitsky PK, Gates FL. EXPERIMENTAL STUDIES OF THE NASOPHARYNGEAL SECRETIONS FROM INFLUENZA PATIENTS : I. TRANSMISSION EXPERIMENTS WITH NASOPHARYNGEAL WASHINGS. J Exp Med. 1921 Jan 31;33(2):125-45.Pubmed PMID: 19868484.
[35]. Moore LV, Moore WE. Oribaculum catoniae gen. nov., sp. nov.; Catonella morbi gen. nov., sp. nov.; Hallella seregens gen. nov., sp. nov.; Johnsonella ignava gen. nov., sp. nov.; and Dialister pneumosintes gen. nov., comb. nov., nom. rev., Anaerobic gram-negative bacilli from the human gingival crevice. Int J Syst Bacteriol. 1994 Apr;44(2):187-92.Pubmed PMID: 8186083.
[36]. Jumas-Bilak E, Jean-Pierre H, Carlier JP, Teyssier C, Bernard K, Gay B, et al. Dialister micraerophilus sp. nov. and Dialister propionicifaciens sp. nov., isolated from human clinical samples. Int J Syst Evol Microbiol. 2005 Nov;55(Pt 6):2471-2478.Pubmed PMID: 16280512.
[37]. Doan N, Contreras A, Flynn J, Slots J, Chen C. Molecular identification of Dialister pneumosintes in subgingival plaque of humans. J Clin Microbiol. 2000 Aug;38(8):3043-7.Pubmed PMID: 10921975.
[38]. Colombo AP, Boches SK, Cotton SL, Goodson JM, Kent R, Haffajee AD, et al. Comparisons of subgingival microbial profiles of refractory periodontitis, severe periodontitis, and periodontal health using the human oral microbe identification microarray. J Periodontol. 2009 Sep;80(9):1421-32.Pubmed PMID: 19722792.
[39]. Silva-Boghossian CM, Neves AB, Resende FA, Colombo AP. Suppurationassociated bacteria in patients with chronic and aggressive periodontitis. J Periodontol. 2013 Sep;84(9):e9-e16.Pubmed PMID: 23327648.
[40]. Kamma JJ, Contreras A, Slots J. Herpes viruses and periodontopathic bacteria in early-onset periodontitis. J Clin Periodontol. 2001 Sep;28(9):879-85. Pubmed PMID: 11493359.
[41]. Ferraro CT, Gornic C, Barbosa AS, Peixoto RJ, Colombo AP. Detection of Dialister pneumosintes in the subgingival biofilm of subjects with periodontal disease. Anaerobe. 2007 Oct-Dec;13(5-6):244-8.Pubmed PMID: 17980633.
[42]. Moore LV, Johnson JL, Moore WE. Selenomonas noxia sp. nov., Selenomonas flueggei sp. nov., Selenomonas infelix sp. nov., Selenomonas dianae sp. nov., and Selenomonas artemidis sp. nov., from the human gingival crevice. Int J Syst Evol Microbiol. 1987 Jul 1;37(3):271-80.
[43]. Maiden MF, Tanner A, Moore WE. Identification of Selenomonas species by whole-genomic DNA probes, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, biochemical tests and cellular fatty acid analysis. Oral Microbiol Immunol. 1992 Feb;7(1):7-13.Pubmed PMID: 1528628.
[44]. Hofstad T, Naess V, Skaug N. Biological activity of lipopolysaccharides from oral Selenomonas. Scand J Dent Res. 1986 Dec;94(6):515-20.Pubmed PMID: 3468599.
[45]. Deng K, Ouyang XY, Chu Y, Zhang Q. Subgingival Microbiome of Gingivitis in Chinese Undergraduates. Chin J Dent Res. 2017;20(3):145-152. Pubmed PMID: 28808698.
[46]. Haapasalo M, Ranta H, Shah H, Ranta K, Lounatmaa K, Kroppenstedt RM. Mitsuokella dentalis sp. nov. from dental root canals. Int J Syst Evol Microbiol. 1986 Oct 1;36(4):566-8.
[47]. Flynn MJ, Li G, Slots J. Mitsuokella dentalis in human periodontitis. Oral Microbiol Immunol. 1994 Aug;9(4):248-50.Pubmed PMID: 7478766.
[48]. Haapasalo M, Ranta H, Shah H, Ranta K, Lounatmaa K, Kroppenstedt RM. Biochemical and structural characterization of an unusual group of gram-negative, anaerobic rods from human periapical osteitis. J Gen Microbiol. 1986 Feb;132(2):417-26.Pubmed PMID: 2872267.
[49]. Shah HN, Collins DM. Prevotella, a new genus to include Bacteroides melaninogenicus and related species formerly classified in the genus Bacteroides. Int J Syst Bacteriol. 1990 Apr;40(2):205-8.Pubmed PMID: 2223612.
[50]. Choi BK, Paster BJ, Dewhirst FE, Göbel UB. Diversity of cultivable and uncultivable oral spirochetes from a patient with severe destructive periodontitis. Infect Immun. 1994 May;62(5):1889-95.Pubmed PMID: 8168954.
[51]. Moter A, Hoenig C, Choi BK, Riep B, Göbel UB. Molecular epidemiology of oral treponemes associated with periodontal disease. J Clin Microbiol. 1998 May;36(5):1399-403.Pubmed PMID: 9574713.
[52]. Park KK, Heuner K, Göbel UB, Yoo YJ, Kim CK, Choi BK. Cloning and characterization of a major surface protein (MspTL) of Treponema lecithinolyticum associated with rapidly progressive periodontitis. FEMS Microbiol Lett. 2002 Feb 5;207(2):185-92.Pubmed PMID: 11958938.
[53]. Jun HK, Lee HR, Lee SH, Choi BK. Mapping of the proinflammatory domains of MspTL of Treponema lecithinolyticum. Microbiology (Reading). 2007 Aug;153(Pt 8):2386-2392.Pubmed PMID: 17660403.
[54]. Choi BK, Jung JH, Suh HY, Yoo YJ, Cho KS, Chai JK, et al. Activation of matrix metalloproteinase-2 by a novel oral spirochetal species Treponema lecithinolyticum. J Periodontol. 2001 Nov;72(11):1594-600.Pubmed PMID: 11759872.
[55]. Lee SH, Kim KK, Choi BK. Upregulation of intercellular adhesion molecule 1 and proinflammatory cytokines by the major surface proteins of Treponema maltophilum and Treponema lecithinolyticum, the phylogenetic group IV oral spirochetes associated with periodontitis and endodontic infections. Infect Immun. 2005 Jan;73(1):268-76.Pubmed PMID: 15618163.
[56]. Edwards AM, Jenkinson HF, Woodward MJ, Dymock D. Binding properties and adhesion-mediating regions of the major sheath protein of Treponema denticola ATCC 35405. Infect Immun. 2005 May;73(5):2891-8.Pubmed PMID: 15845495.
[57]. Lee SH, Kim KK, Choi BK. Upregulation of intercellular adhesion molecule 1 and proinflammatory cytokines by the major surface proteins of Treponema maltophilum and Treponema lecithinolyticum, the phylogenetic group IV oral spirochetes associated with periodontitis and endodontic infections. Infect Immun. 2005 Jan;73(1):268-76.Pubmed PMID: 15618163.
[58]. Vartoukian SR, Palmer RM, Wade WG. Diversity and morphology of members of the phylum "synergistetes" in periodontal health and disease. Appl Environ Microbiol. 2009 Jun;75(11):3777-86.Pubmed PMID: 19346352. [59]. Siqueira JF Jr, Rôças IN. Molecular detection and identification of Synergistes phylotypes in primary endodontic infections. Oral Dis. 2007 Jul;13(4):398-401.Pubmed PMID: 17577326.
[60]. Hugenholtz P, Goebel BM, Pace NR. Impact of culture-independent studies on the emerging phylogenetic view of bacterial diversity. J Bacteriol. 1998 Sep;180(18):4765-74. doi: 10.1128/JB.180.18.4765-4774.1998. Erratum in: J Bacteriol 1998 Dec;180(24):6793.Pubmed PMID: 9733676.
[61]. Vartoukian SR, Downes J, Palmer RM, Wade WG. Fretibacterium fastidiosum gen. nov., sp. nov., isolated from the human oral cavity. Int J Syst Evol Microbiol. 2013 Feb;63(Pt 2):458-463.Pubmed PMID: 22493171.
[62]. Khemwong T, Kobayashi H, Ikeda Y, Matsuura T, Sudo T, Kano C, et al. Fretibacterium sp. human oral taxon 360 is a novel biomarker for periodontitis screening in the Japanese population. PLoS One. 2019 Jun 19;14(6):e0218266.Pubmed PMID: 31216300.
[63]. Belibasakis GN, Oztürk VÖ, Emingil G, Bostanci N. Synergistetes cluster A in saliva is associated with periodontitis. J Periodontal Res. 2013 Dec;48(6):727-32.Pubmed PMID: 23441995.
[64]. You M, Mo S, Watt RM, Leung WK. Prevalence and diversity of Synergistetes taxa in periodontal health and disease. J Periodontal Res. 2013 Apr;48(2):159-68.Pubmed PMID: 22881378.
[65]. Scher JU, Ubeda C, Equinda M, Khanin R, Buischi Y, Viale A, et al. Periodontal disease and the oral microbiota in new-onset rheumatoid arthritis. Arthritis Rheum. 2012 Oct;64(10):3083-94.Pubmed PMID: 22576262.
[66]. Chugal N, Wang JK, Wang R, He X, Kang M, Li J, et al. Molecular characterization of the microbial flora residing at the apical portion of infected root canals of human teeth. J Endod. 2011 Oct;37(10):1359-64.Pubmed PMID: 21924182.
[67]. Camelo-Castillo A, Novoa L, Balsa-Castro C, Blanco J, Mira A, Tomás I. Relationship between periodontitis-associated subgingival microbiota and clinical inflammation by 16S pyrosequencing. J Clin Periodontol. 2015 Dec;42(12):1074-82.Pubmed PMID: 26461079.
[68]. Bao K, Papadimitropoulos A, Akgül B, Belibasakis GN, Bostanci N. Establishment of an oral infection model resembling the periodontal pocket in a perfusion bioreactor system. Virulence. 2015;6(3):265-73.Pubmed PMID: 25587671.
[69]. Bao K, Bostanci N, Thurnheer T, Belibasakis GN. Proteomic shifts in multispecies oral biofilms caused by Anaeroglobus geminatus. Sci Rep. 2017 Jun 30;7(1):4409.Pubmed PMID: 28667274.
[70]. Cross KL, Chirania P, Xiong W, Beall CJ, Elkins JG, Giannone RJ, et al. Insights into the Evolution of Host Association through the Isolation and Characterization of a Novel Human Periodontal Pathobiont, Desulfobulbus oralis. mBio. 2018 Mar 13;9(2):e02061-17.Pubmed PMID: 29535201.
[71]. Shi M, Wei Y, Hu W, Nie Y, Wu X, Lu R. The Subgingival Microbiome of Periodontal Pockets With Different Probing Depths in Chronic and Aggressive Periodontitis: A Pilot Study. Front Cell Infect Microbiol. 2018 May 1;8:124.Pubmed PMID: 29765908.
[72]. Ferrari A, Brusa T, Rutili A, Canzi E, Biavati B. Isolation and characterization of Methanobrevibacter oralis sp. nov. Curr. Microbiol. 1994 Jul;29(1):7-12.
[73]. Li CL, Liu DL, Jiang YT, Zhou YB, Zhang MZ, Jiang W, et al. Prevalence and molecular diversity of Archaea in subgingival pockets of periodontitis patients. Oral Microbiol Immunol. 2009 Aug;24(4):343-6.Pubmed PMID: 19572899.
[74]. Lepp PW, Brinig MM, Ouverney CC, Palm K, Armitage GC, Relman DA. Methanogenic Archaea and human periodontal disease. Proc Natl Acad Sci U S A. 2004 Apr 20;101(16):6176-81.Pubmed PMID: 15067114.
[75]. Matarazzo F, Ribeiro AC, Feres M, Faveri M, Mayer MP. Diversity and quantitative analysis of Archaea in aggressive periodontitis and periodontally healthy subjects. J Clin Periodontol. 2011 Jul;38(7):621-7.Pubmed PMID: 21539593.
[76]. Belkacemi S, Mazel A, Tardivo D, Tavitian P, Stephan G, Bianca G, et al. Peri-implantitis-associated methanogens: a preliminary report. Sci Rep. 2018 Jun 21;8(1):9447.Pubmed PMID: 29930395.
