Non-Cochrane · aetiology · PM41820934
Extraction of first primary molars and significance of space loss: a systematic review and meta-analysis.
El-Motayam Ahmed Kamal, Hassan Mostafa A, Sadek Mais Medhat, et al. · BMC oral health · 2026 · PubMed · doi:10.1186/s12903-026-07934-2
Findings
Population Children aged 4-9 years requiring extraction of a first primary molar (Ds)
12 findings
| Extraction of a maxillary first primary molar | Contralateral non-extraction side in the same child (split-mouth control) | Space loss (D or D+E space, mm), extraction side minus control side 9-12 months · Leave-one-out sensitivity: omitting Park 2009 | MD -0.6 [-0.91, -0.3] GRADE not reported 3 studies |
| Extraction of a maxillary first primary molar | Contralateral non-extraction side in the same child (split-mouth control) | Space loss (D or D+E space, mm), extraction side minus control side 9-12 months · Leave-one-out sensitivity: omitting Alexander 2015 | MD -0.52 [-0.97, -0.08] GRADE not reported 3 studies |
| Extraction of a maxillary first primary molar | Contralateral non-extraction side in the same child (split-mouth control) | Space loss (D or D+E space, mm), extraction side minus control side 9-12 months | MD -0.52 [-0.79, -0.26] GRADE not reported 4 studies · 141 participants |
| Extraction of a maxillary first primary molar | Contralateral non-extraction side in the same child (split-mouth control) | Space loss (D or D+E space, mm), extraction side minus control side 9-12 months · Leave-one-out sensitivity: omitting Lin 2011 | MD -0.5 [-0.77, -0.23] GRADE not reported 3 studies |
| Extraction of a maxillary first primary molar | Contralateral non-extraction side in the same child (split-mouth control) | Space loss (D or D+E space, mm), extraction side minus control side 9-12 months · Leave-one-out sensitivity: omitting Kundra 2024 | MD -0.48 [-0.75, -0.21] GRADE not reported 3 studies |
| Extraction of a mandibular first primary molar | Contralateral non-extraction side in the same child (split-mouth control) | Space loss (D or D+E space, mm), extraction side minus control side 8-9 months · Leave-one-out sensitivity: omitting Alexander 2015 | MD -1.78 [-2.09, -1.47] GRADE not reported 3 studies |
| Extraction of a mandibular first primary molar | Contralateral non-extraction side in the same child (split-mouth control) | Space loss (D or D+E space, mm), extraction side minus control side 8-9 months · Leave-one-out sensitivity: omitting Kundra 2024 | MD -1.45 [-1.97, -0.93] GRADE not reported 3 studies |
| Extraction of a mandibular first primary molar | Contralateral non-extraction side in the same child (split-mouth control) | Space loss (D or D+E space, mm), extraction side minus control side 8-9 months · After excluding Alexander 2015, fixed-effect model (final estimate) | MD -1.78 [-2.09, -1.47] GRADE not reported 3 studies · 171 participants |
| Extraction of a mandibular first primary molar | Contralateral non-extraction side in the same child (split-mouth control) | Space loss (D or D+E space, mm), extraction side minus control side 8-9 months · Leave-one-out sensitivity: omitting Lin and Chang 1998 | MD -1.57 [-2.12, -1.02] GRADE not reported 3 studies |
| Extraction of a mandibular first primary molar | Contralateral non-extraction side in the same child (split-mouth control) | Space loss (D or D+E space, mm), extraction side minus control side 8-9 months · Initial analysis, fixed-effect model (4 studies) | MD -1.51 [-1.74, -1.28] GRADE not reported 4 studies |
| Extraction of a mandibular first primary molar | Contralateral non-extraction side in the same child (split-mouth control) | Space loss (D or D+E space, mm), extraction side minus control side 8-9 months · Leave-one-out sensitivity: omitting Padma and Retnakumari 2006 | MD -1.22 [-1.55, -0.9] GRADE not reported 3 studies |
| Extraction of a mandibular first primary molar | Contralateral non-extraction side in the same child (split-mouth control) | Space loss (D or D+E space, mm), extraction side minus control side 8-9 months · Initial analysis, random-effects model (4 studies) | MD -1.52 [-1.99, -1.04] GRADE not reported 4 studies |
Included primary studies 7
Open in Studies| Study | Year | Also included by | Outcomes it informs here | Trial data |
|---|---|---|---|---|
| Alexander 2015 The premature loss of primary first molars: space loss to molar occlusal relationships and facial patterns. PMID:25010923 | 2015 | this review only | Space loss (D or D+E space, mm), extraction side minus control side | not extracted yet |
| Kobylinska 2019 Spatial changes in the dental arch after premature extraction of the first primary molar – a 12-month observational study DOI:10.25121/newmed.2019.23.3.96 | 2019 | this review only | not stated | not extracted yet |
| Kundra 2024 Spatial and angular alterations in the dental arch after premature loss of primary molars: Immediate and 9-month computed tomography… PMID:39250207 | 2024 | this review only | Space loss (D or D+E space, mm), extraction side minus control side | not extracted yet |
| Lin 2011 Twelve-month space changes after premature loss of a primary maxillary first molar. PMID:20961344 | 2011 | this review only | Space loss (D or D+E space, mm), extraction side minus control side | not extracted yet |
| Lin and Chang 1998 Space changes after premature loss of the mandibular primary first molar: a longitudinal study. PMID:9796501 | 1998 | this review only | Space loss (D or D+E space, mm), extraction side minus control side | not extracted yet |
| Padma and Retnakumari 2006 Loss of space and changes in the dental arch after premature loss of the lower primary molar: a longitudinal study. PMID:16823234 | 2006 | this review only | Space loss (D or D+E space, mm), extraction side minus control side | not extracted yet |
| Park 2009 Three-dimensional space changes after premature loss of a maxillary primary first molar. PMID:19486367 | 2009 | this review only | Space loss (D or D+E space, mm), extraction side minus control side | not extracted yet |
Review question
| Element | Planned (methods) | Found (results) |
|---|---|---|
| Population | Children aged 4-9 years | Children aged 5-9 years; 141 children in maxillary and 171 in mandibular analyses |
| Intervention | Extraction of a first primary molar (exposure) | Extraction of upper or lower primary first molar (n=7 studies) |
| Comparison | Contralateral non-extraction side in the same patient (split-mouth) | Contralateral control side (n=7 studies) |
| Outcomes | Change in the primary first molar space (D or D+E space) in millimeters | Space loss (D or D+E space) in mm; maxillary (4 studies in meta-analysis) and mandibular (3 to 4 studies) |
| Study designs | Prospective or retrospective cohort studies (split-mouth) | Prospective cohort studies with split-mouth design (n=7) |
| Timing | Follow-up of at least 6 months | Follow-up 8 to 12 months |
AMSTAR 2 items
Two independent extractors rated each item. Their ratings are shown side by side because they have not been reconciled yet. The overall rating follows Shea et al. 2017: one critical flaw gives Low, more than one gives Critically Low.
| Item | Extractor A | Extractor B | Agree |
|---|---|---|---|
| 1Research question includes PICO components | NR | Yes | no |
| 2Protocol established before the reviewcritical | NR | Partial Yes | no |
| 3Choice of study designs explained | NR | Yes | no |
| 4Comprehensive literature searchcritical | NR | Partial Yes | no |
| 5Study selection in duplicate | NR | Yes | no |
| 6Data extraction in duplicate | NR | Yes | no |
| 7List of excluded studies with reasonscritical | NR | Yes | no |
| 8Included studies described in detail | NR | Partial Yes | no |
| 9Risk of bias assessed satisfactorilycritical | NR | NRSI: Yes · RCT: N/A | no |
| 10Funding of included studies reported | NR | No | no |
| 11Appropriate meta-analysis methodscritical | NR | NRSI: Yes · RCT: N/A | no |
| 12Impact of risk of bias on the pooled results | NR | No | no |
| 13Risk of bias accounted for in interpretationcritical | NR | Yes | no |
| 14Heterogeneity explained | NR | Yes | no |
| 15Publication bias investigatedcritical | NR | Yes | no |
| 16Conflicts of interest reported | NR | Yes | no |
| Overall | NR | Moderate | no |