|Year : 2022 | Volume
| Issue : 3 | Page : 239-245
Short- and long-term dental arch spatial changes following premature loss of primary molars: A systematic review
Janvi Manish Gandhi, Deepa Gurunathan
Department of Pediatric and Preventive Dentistry, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India
|Date of Submission||08-May-2022|
|Date of Decision||23-Jun-2022|
|Date of Acceptance||18-Jul-2022|
|Date of Web Publication||18-Oct-2022|
Janvi Manish Gandhi
No. 162, Poonamallee High Road, Chennai - 600 077, Tamil Nadu
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Aim: The aim of this study was to evaluate the dental arch spatial changes in maxillary and mandibular arches after premature loss of primary molars. Introduction: Primary teeth must be maintained during the change from primary to mixed and then permanent dentition, to preserve and maintain the dental arch. When this normal process is disturbed, usually due to severe decay requiring extraction before normal exfoliation, it can result in migration of adjacent teeth toward the missing space resulting in decreased arch length and malocclusion in the permanent dentition. Materials and Methods: A comprehensive search was conducted using electronic databases such as PubMed Central, Cochrane Database of Systematic Reviews, Google Scholar, LILACS, and ScienceDirect. The title and abstract were screened to find relevant articles, which were then reviewed in full to see if they were worthy of inclusion. All longitudinal and observational studies that looked at space changes after the loss of primary first or second molars were included. Quality assessment of the studies was done based on the Newcastle-Ottawa scale as all the included studies were non-randomized studies. Results: Four thousand five hundred and seventy-eight articles were identified by screening electronic database and assessed for eligibility, 12 full-text articles were assessed, and 4 full-text articles were excluded as they did not match the inclusion criteria. Thus, eight articles were included in this systematic review. Short term and long term space changes and loss of maxillary and mandibular molars were studied individually. In the short term changes, the distal migration of the primary cuspid towards the missing space within 1 month was attributable to early space changes after premature loss of the mandibular first molar, and the greatest space loss was recorded in the first 3 months after premature loss. After the premature loss of the maxillary first molar, immediate space loss of 1mm was documented due to distal migration of the primary canine. Studies found that space loss was caused by the distal migration of primary canines in the case of mandibular primary first molar loss, and that space loss was larger in the mandibular arch after premature loss of second primary molars. Conclusion: The greatest repercussions occurred during the first 3 months after the deciduous molars were extracted, and a space maintainer was recommended in the majority of cases, mainly when there is premature loss of mandibular second primary molar as it leads to mesial displacement of the first permanent molar.
Keywords: Arch changes, extraction, premature loss, primary molars, space changes
|How to cite this article:|
Gandhi JM, Gurunathan D. Short- and long-term dental arch spatial changes following premature loss of primary molars: A systematic review. J Indian Soc Pedod Prev Dent 2022;40:239-45
|How to cite this URL:|
Gandhi JM, Gurunathan D. Short- and long-term dental arch spatial changes following premature loss of primary molars: A systematic review. J Indian Soc Pedod Prev Dent [serial online] 2022 [cited 2022 Dec 5];40:239-45. Available from: http://www.jisppd.com/text.asp?2022/40/3/239/358833
| Introduction|| |
Primary teeth are commonly associated with dental caries due to their morphology, dietary habits of children, and the improper feeding practices. Increase in caries activity leads to severe decay resulting in the need for extraction of these teeth prior to normal exfoliation. Premature loss of primary teeth usually results in need for complex orthodontic treatment later on due to reasons like space loss. Primary teeth must be maintained during the transition from primary dentition to mixed, and then permanent dentition, in order to preserve and maintain the dental arch. When this natural process is disrupted, it may lead to migration of adjacent teeth resulting in loss of the arch length or arch asymmetry which manifests as malocclusion. It is rightly quoted that a natural tooth is the best space maintainer.
In 1998, Lin and Chang were the first to quantify the loss of space caused by early extraction of deciduous molars. They found that the predominant cause of space alterations in the mandibular arch was distal displacement of the primary canine, which could be up to 1–1.5 mm toward the extraction site after 8 months. Growth and development of teeth and their drifting patterns are dependent on each other. Harmful complications such as tipping of permanent molars, crowding, and impacted permanent teeth, especially permanent canines, can occur due to loss of space in the primary or mixed dentition. The requirement for a space maintainer after the early loss of primary second molar is less debated than the need for management of space after premature loss of primary first molar. Based on scientific evidence, premature loss of primary second molar leads to increased space loss when compared to that following primary first molar loss and it is greater in the mandibular arch than that in the maxillary arch. These findings warrant the need and rationale behind this systematic review, which was done to evaluate the scientific evidence associated with space loss occurring after premature loss of primary molars. Evaluation of the right amount of space loss based on the current scientific evidence available would be beneficial to prevent arch asymmetry or decrease in intra-arch space as this may influence further treatment options.
This systematic review aims to evaluate the dental arch spatial changes in maxillary and mandibular arches after premature loss of deciduous molars.
| Materials and Methods|| |
Protocol and registration
This systematic review is registered under PROSPERO (CRD42021255881).
This systematic review was carried out according to a preexisting protocol following the guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement [Table 1].
Search was conducted till December 2021 and the studies were chosen based on the following inclusion criteria:
- All longitudinal studies and observational studies studying space changes after premature loss of primary first or/and second molars
- Split-mouth studies comparing one side with premature loss of molars with no loss of molars on the other side of the same arch
- Studies only in the English language.
Studies were eliminated based on the following exclusion criteria:
- Case reports or case series
- Animal studies
- Cross-sectional studies.
Types of participants – children between 6 and 9 years with premature loss of primary first and second molars in either the maxilla or mandible.
Types of interventions – this search included spatial/space changes following extraction; it included groups with extraction and control groups without extraction and also split-mouth studies.
Types of outcomes – studies measuring short-term (6 months) and long-term (81 months) spatial changes, measuring of outcomes before and after tooth loss, as well as at certain intervals during the follow-up period.
The following electronic databases were searched from 1998 up to December 2020: MEDLINE (via PubMed) [Figure 1], the Cochrane Central Register of Controlled Trials/the Cochrane Library [Figure 2], LILACS [Figure 3], Google Scholar [Figure 4], and ScienceDirect [Figure 5]. Search terms used in this literature search were “primary molars,” “space changes,” “space loss,” “short term changes,” “long term changes,” “premature tooth loss,” and “tooth/teeth extraction//loss.” When more information on a particular publication was required, attempts were made to contact the authors.
PubMed search strategy
(molar OR molars) OR (tooth OR teeth) AND (primary OR deciduous) AND (loss OR extract) OR (extraction OR exfoliate OR exfoliated) AND (migration OR drift OR drifting) OR (space) OR (change OR changes) OR (eruption OR position) OR (closure OR effect OR effects) OR (result OR results).
COCHRANE search strategy
(primary teeth OR primary tooth) OR (deciduous teeth OR deciduous tooth) AND (premature loss OR extract OR molar extraction) AND (mesial migration OR drift OR drifting) OR (space OR arch perimeter OR change OR changes) OR (space closure OR effect OR effects OR result OR results).
LILACS search strategy
(primary teeth OR primary tooth) OR (deciduous teeth OR deciduous tooth) AND (loss OR extract OR extraction OR extracted OR exfoliate OR exfoliation OR exfoliated) AND (migration OR drift) OR space loss OR arch changes OR arch perimeter OR space closure OR effect OR effects OR results).
ScienceDirect search strategy
Primary molars OR deciduous molars OR primary teeth OR primary first molar OR primary second molar AND premature loss AND premature extraction AND space changes AND dental arch.
Google Scholar search strategy
Google Scholar database was searched using the following keywords: primary molars, premature loss, migration of teeth, extraction, space changes, dental arch changes, short term changes, and long term changes.
One author (Janvi Gandhi [JG] carried out the search strategy from the individual databases. The cumulative titles obtained were scanned and independently evaluated by two authors, JG and Deepa Gurunathan (DG), to identify the studies most relevant. The studies that were duplicated in multiple databases were eliminated. In the event of a disagreement between the two authors, a final decision was reached through debate between the two authors. When complete information on the groups and people included in the studies was not given in the title, the abstracts were assessed. Two authors, JG and DG, independently evaluated abstracts to determine the final papers to be included based on the inclusion and exclusion criteria. When the abstracts did not provide enough information, full-text publications were assessed. The abstracts of the papers that appeared to meet the inclusion/exclusion criteria were chosen. All of the selected papers' references were checked for articles that might not have been in the databases for various reasons. Data collection forms were used to record the desired information, such as details on study design, bibliography details, participant, intervention and outcome characteristics, and verification of study eligibility.
The first author (JG) performed the detailed data search and the first and second author (JG and DG) performed data extraction independently and then scrutinized them together using a data extraction form. The following characteristics were included:
- Author and year of study
- Study design
- Sample size and age group
- Premature loss of which tooth
- Maxillary or mandibular arch
- Follow-up period
- Outcome assessed.
Risk of bias
The Newcastle–Ottawa scale was used to assess the quality of the studies. As the included studies were all observational studies (nonrandomized studies), an accurate risk of bias cannot be done, hence only quality assessment was done. This scale was scored by awarding a point for each answer. Possible total points are 4 points for selection, 2 points for comparability, and 3 points for outcomes [Figure 6].
|Figure 6: The Newcastle Ottawa scale for quality assessment of observational studies|
Click here to view
| Results|| |
Four thousand five hundred and seventy-eight articles were identified by screening electronic databases and assessed for eligibility. Three thousand seven hundred and ninety-eight articles were excluded after reading the title. Seven hundred and eighty articles were screened, out of which 768 were excluded based on their abstract. Twelve full-text articles were assessed. Four full-text articles were excluded as they did not match the inclusion criteria. Thus, eight articles were included in this systematic review. Based on the quality assessment using Newcastle Ottawa scale, the highest score was obtained by the study by Lin et al, 2017 and the least score was obtained by Lin et al, 2007 among the studies included [Figure 6].
In all the included studies, studies by Lin et al., 1998, and Padma Kumari and Retnakumari, 2006, had a short-term follow-up (6 months). Both of these studies evaluated space changes after early loss of the first molar. Padma Kumari and Retnakumari studied the changes in mandibular arch and found that the distal movement of the primary canine toward the extraction space is most likely responsible for the early space change of the mandibular dental arch after premature loss of the mandibular first primary molar, and the greatest space loss was observed in the first 4 months after premature extraction. Lin et al. studied the changes in the maxillary arch and also found similar results; that space loss was attributed to distal movement of primary canine. Another study in 2019 evaluated space changes following loss of primary second molar after a follow-up of 3 weeks, but this study was not included in this review due to the shorter follow-up period [Figure 7].
All the included studies which had a follow-up period more than 6 months were included under the long-term follow-up outcome. Lin et al. had the longest follow-up period of 81 months followed by Northway et al [Figure 8]. They concluded that the arch dimensions significantly increased after 81 months which suggested that space maintainers were not needed in these cases. The other included studies with a 12-month follow-up period found that after early loss of the primary first molar, 12-month space changes predominantly consisted of distal drift of the primary canine toward the missing space.
Studies were done in 1998, 2006, 2011, and the latest study done in 2016 on space loss due to premature loss of primary molars. Lin et al. discovered that the reduction in arch space following the premature loss of second primary molars in the maxilla and mandible had a bigger unfavorable impact on occlusion than the loss of first primary molars. Extensive changes in arch dimensions were seen after premature loss of primary maxillary first molar in a study involving a follow-up period of 81 months, which was the longest follow-up period in all the included studies. They evaluated the unilateral premature loss of primary maxillary first molar in nine children (6 years). Their results suggested that space maintainers were not needed in cases where the first permanent molar was partially erupted or fully erupted.,
Northway et al. concluded that this loss was attributable to the mesial migration of second deciduous molars, while Lin et al. believed that it was due to the distal migration of deciduous canines and incisors.,
Space changes in both maxilla and mandible after premature loss of first and second molars were studied, and they concluded that the dental arches experienced the most consequences in the first 3 months after the deciduous molars were extracted. A space maintainer is indicated the most in cases where there is premature loss of mandibular second deciduous molar as it exhibits mesial movement of the first permanent molar.
Loss of maxillary primary molars
Space loss by premature loss of maxillary first or second molars was studied in majority of the studies included in this systematic review (4, 5, 6, 7, and 8 in the table) and they concluded that the space loss was due to distal movement of primary canine. It was found that after the early loss of the maxillary first molar, immediate space loss occurred, resulting in a reduction in arch length despite an increase in intercanine width.
Loss of mandibular primary molars
Space loss by premature loss of mandibular first or second molars was studied in three of the included studies (2, 3, and 8 in the table). These studies also concluded that space loss was due to the distal migration of primary canines and space loss was greater in mandibular arch after premature loss of second primary molars. More space (0.25 mm each month) was initially lost at the extraction site when the mandibular first primary molar was lost. At the follow-up, space loss was lesser (1.5 mm).,
| Discussion|| |
The objective of this systematic review was to evaluate and scrutinize the scientific evidence around the spatial changes related with the early loss of primary first and second molars in the maxillary and mandibular arches. The outcome assessed in this systematic review of all the included studies was the short- and long-term spatial changes. Previous literature review done similar to this topic was in 2007 and then in 2017, but both these SRs included only the space changes after premature loss of first primary molars. Tunison et al. conducted a systematic review that covered all research analyzing space loss up through June 2007 and determined that just 3 of the 79 studies could be included. Methodological evaluation was done using a methodological score list where a maximum of 15 points could be given. The results of this methodological assessment were similar to the quality assessment done in this systematic review using the Newcastle–Ottawa scale where Lin et al. and Padma Kumari and Retnakumari scored highest points. Risk of bias in the previous systematic review was considered moderate or unclear as blinding was not possible and the follow-up period in the included studies (only two studies matched their inclusion criteria) were not long enough. This review provides more elaborate data as it includes studies evaluating premature loss of both first and second molars and both the maxillary and mandibular arches.
Twelve full articles were assessed in this review, out of which four were excluded due to the reasons mentioned and finally eight were included [Figure 8]. The study by Lin et al. had the longest follow-up period of 81 months in all the studies included. It is suggested that tooth movement to the extracted site depends on various factors such as type of tooth extracted, maxillary or mandibular arch, whether the tooth was lost or extracted, eruptive stage of the permanent successor, tooth eruption sequence, and various other factors.
This review included articles which studied premature loss of first molars and those studies which included spatial changes due to premature loss of first and second molars and it was found that after the loss of the first primary molar, the position of the first permanent molar and the deciduous canine remained unchanged., Only the children with loss of the mandibular second molars exhibited mesial movement of the first permanent molar, which was assessed with the arch length measurement. Space maintainers are indicated mainly in cases where there is a possible mesial drift of first permanent molar as it causes a risk of impacted permanent teeth or future crowding. Whereas in cases after extraction of maxillary 2nd primary molar, need for a space maintainer was not as much, as the space loss occurred in the first 3 months and was easily compensated.
The most significant changes in the dental arches happened within the first 3 months after the primary molars were extracted.
Lin et al. conducted the most elaborate research on this topic as they assessed short-term (6 months) and long-term (81 months) follow-up periods. It was found that within the first 8 months, there was distal drift of the primary canine (1-1.5mm) in the lower arch, towards the missing space. In 2007, they discovered a comparable distal drift of the deciduous canine, with space loss of up to 1 mm within 6 months of the extraction. In 2011, an extended study was conducted with a 12-month follow-up and it was discovered that the mesial drift of permanent first molars can be prevented by increasing intercanine width, implying that space maintainers might not always be required, especially in cases involving early primary first molar loss. Later, it was found that there was a significant increase in the arch dimensions after a follow up period of 81 months. It was found that there was a significant increase in the arch dimensions after a follow-up period of 81 months.
This review was conducted following the proper PRISMA 2009 guidelines, but it still had a few limitations. The quality of evidence would be low as all the included studies are observational studies and meta-analysis was not possible due to the heterogeneity of the studies included. The clinical significance of space loss after premature loss of molars and the need to provide space maintainers is very subjective, different for each case. Hence, it needs to be decided based on a comprehensive assessment of the missing space and all the other parameters discussed in detail in this systematic review.
| Conclusion|| |
Based on the limitations of this review, it is safe to conclude that the most severe consequences of the dental arches occurred within the first 3 months after the deciduous molars were lost, and that a space maintainer is most commonly indicated in cases, primarily when the mandibular second primary molar is lost prematurely, as it leads to mesial movement of the first permanent molar.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Lin YT, Chang LC. Space changes after premature loss of the mandibular primary first molar: A longitudinal study. J Clin Pediatr Dent 1998;22:311-6.
Lin YJ, Lin YT. Long-term space changes after premature loss of a primary maxillary first molar. J Dent Sci 2017;12:44-8.
Lin YT, Lin WH, Lin YT. Immediate and six-month space changes after premature loss of a primary maxillary first molar. J Am Dent Assoc 2007;138:362-8.
Padma Kumari B, Retnakumari N. Loss of space and changes in the dental arch after premature loss of the lower primary molar: A longitudinal study. J Indian Soc Pedod Prev Dent 2006;24:90-6.
Bindayel NA. Clinical evaluation of short term space variation following premature loss of primary second molar, at early permanent dentition stage. Saudi Dent J 2019;31:311-5.
Northway WM, Wainright RL, Demirjian A. Effects of premature loss of deciduous molars. Angle Orthod 1984;54:295-329.
Lin YT, Lin WH, Lin YT. Twelve-month space changes after premature loss of a primary maxillary first molar. Int J Paediatr Dent 2011;21:161-6.
Terlaje RD, Donly KJ. Treatment planning for space maintenance in the primary and mixed dentition. ASDC J Dent Child 2001;68:109-14, 80.
Macena MC, Tornisiello Katz CR, Heimer MV, de Oliveira e Silva JF, Costa LB. Space changes after premature loss of deciduous molars among Brazilian children. Am J Orthod Dentofacial Orthop 2011;140:771-8.
Tunison W, Flores-Mir C, ElBadrawy H, Nassar U, El-Bialy T. Dental arch space changes following premature loss of primary first molars: A systematic review. Pediatr Dent 2008;30:297-302.
Kaklamanos EG, Lazaridou D, Tsiantou D, Kotsanos N, Athanasiou AE. Dental arch spatial changes after premature loss of first primary molars: A systematic review of controlled studies. Odontology 2017;105:364-74.
Vitral RW, Fraga MR, Campos MJ. Space changes after premature loss of deciduous molars. Am J Orthod Dentofac Orthop 2012;141:672.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]