Effects of the loss and reconstruction of molar occlusal support on memory retrieval and hippocampal neuron density in rats

Akimasa Kurozumi, Tetsuya Hara, Shunichi Sakamoto, Daisuke Araki, Sachiyo Iida-Tamada, Chisa Kuroda-Ishimine, Shougo Minagi

Research output: Contribution to journalArticle

Abstract

Purpose: Animal experiments have shown that the loss of occlusal support causes impairments in spatial cognition. Many reports have focused on the memory encoding process, and only few studies have investigated the effect on memory retrieval. This study aimed to examine the effects of both the loss and reconstruction of occlusal support on the memory retrieval process and on the number of hippocampal pyramidal cells. Methods: The experimental animals were divided into a molarless group, in which molars were extracted, a denture-wearing molarless group with experimental dentures inserted after molar extraction, and a control group. Radial maze trials were performed for 20 consecutive days (acquisition phase). The rats were tested on long-term memory retention following the acquisition phase in eight trials every five days, and in an additional trial 20 days later (probe phase). Results: The denture-wearing molarless group showed higher levels of spatial learning and memory than the molarless group. There were no significant differences in memory retrieval during the probe phase between the denture-wearing molarless and the control group. The molarless group showed significantly worse spatial learning and memory and had fewer neurons in the hippocampus than the control group. Conclusions: Our results suggest that the loss of occlusal support decreases the number of pyramidal cells in the hippocampus and impairs memory decoding and retrieval. However, this effect is suppressed by the reconstruction of occlusal support.

Original languageEnglish
JournalJournal of Prosthodontic Research
DOIs
Publication statusAccepted/In press - Jan 1 2019

Fingerprint

Dentures
Neurons
Pyramidal Cells
Control Groups
Hippocampus
Long-Term Memory
Cognition
Spatial Learning
Spatial Memory

Keywords

  • Hippocampal neurons
  • Loss of molar teeth
  • Memory retrieval
  • Occlusal support
  • Rat

ASJC Scopus subject areas

  • Oral Surgery
  • Dentistry (miscellaneous)

Cite this

Effects of the loss and reconstruction of molar occlusal support on memory retrieval and hippocampal neuron density in rats. / Kurozumi, Akimasa; Hara, Tetsuya; Sakamoto, Shunichi; Araki, Daisuke; Iida-Tamada, Sachiyo; Kuroda-Ishimine, Chisa; Minagi, Shougo.

In: Journal of Prosthodontic Research, 01.01.2019.

Research output: Contribution to journalArticle

@article{dcad87af66b745c78515d1a99b9764bb,
title = "Effects of the loss and reconstruction of molar occlusal support on memory retrieval and hippocampal neuron density in rats",
abstract = "Purpose: Animal experiments have shown that the loss of occlusal support causes impairments in spatial cognition. Many reports have focused on the memory encoding process, and only few studies have investigated the effect on memory retrieval. This study aimed to examine the effects of both the loss and reconstruction of occlusal support on the memory retrieval process and on the number of hippocampal pyramidal cells. Methods: The experimental animals were divided into a molarless group, in which molars were extracted, a denture-wearing molarless group with experimental dentures inserted after molar extraction, and a control group. Radial maze trials were performed for 20 consecutive days (acquisition phase). The rats were tested on long-term memory retention following the acquisition phase in eight trials every five days, and in an additional trial 20 days later (probe phase). Results: The denture-wearing molarless group showed higher levels of spatial learning and memory than the molarless group. There were no significant differences in memory retrieval during the probe phase between the denture-wearing molarless and the control group. The molarless group showed significantly worse spatial learning and memory and had fewer neurons in the hippocampus than the control group. Conclusions: Our results suggest that the loss of occlusal support decreases the number of pyramidal cells in the hippocampus and impairs memory decoding and retrieval. However, this effect is suppressed by the reconstruction of occlusal support.",
keywords = "Hippocampal neurons, Loss of molar teeth, Memory retrieval, Occlusal support, Rat",
author = "Akimasa Kurozumi and Tetsuya Hara and Shunichi Sakamoto and Daisuke Araki and Sachiyo Iida-Tamada and Chisa Kuroda-Ishimine and Shougo Minagi",
year = "2019",
month = "1",
day = "1",
doi = "10.1016/j.jpor.2018.12.009",
language = "English",
journal = "Journal of Prosthodontic Research",
issn = "1883-1958",
publisher = "Elsevier BV",

}

TY - JOUR

T1 - Effects of the loss and reconstruction of molar occlusal support on memory retrieval and hippocampal neuron density in rats

AU - Kurozumi, Akimasa

AU - Hara, Tetsuya

AU - Sakamoto, Shunichi

AU - Araki, Daisuke

AU - Iida-Tamada, Sachiyo

AU - Kuroda-Ishimine, Chisa

AU - Minagi, Shougo

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Purpose: Animal experiments have shown that the loss of occlusal support causes impairments in spatial cognition. Many reports have focused on the memory encoding process, and only few studies have investigated the effect on memory retrieval. This study aimed to examine the effects of both the loss and reconstruction of occlusal support on the memory retrieval process and on the number of hippocampal pyramidal cells. Methods: The experimental animals were divided into a molarless group, in which molars were extracted, a denture-wearing molarless group with experimental dentures inserted after molar extraction, and a control group. Radial maze trials were performed for 20 consecutive days (acquisition phase). The rats were tested on long-term memory retention following the acquisition phase in eight trials every five days, and in an additional trial 20 days later (probe phase). Results: The denture-wearing molarless group showed higher levels of spatial learning and memory than the molarless group. There were no significant differences in memory retrieval during the probe phase between the denture-wearing molarless and the control group. The molarless group showed significantly worse spatial learning and memory and had fewer neurons in the hippocampus than the control group. Conclusions: Our results suggest that the loss of occlusal support decreases the number of pyramidal cells in the hippocampus and impairs memory decoding and retrieval. However, this effect is suppressed by the reconstruction of occlusal support.

AB - Purpose: Animal experiments have shown that the loss of occlusal support causes impairments in spatial cognition. Many reports have focused on the memory encoding process, and only few studies have investigated the effect on memory retrieval. This study aimed to examine the effects of both the loss and reconstruction of occlusal support on the memory retrieval process and on the number of hippocampal pyramidal cells. Methods: The experimental animals were divided into a molarless group, in which molars were extracted, a denture-wearing molarless group with experimental dentures inserted after molar extraction, and a control group. Radial maze trials were performed for 20 consecutive days (acquisition phase). The rats were tested on long-term memory retention following the acquisition phase in eight trials every five days, and in an additional trial 20 days later (probe phase). Results: The denture-wearing molarless group showed higher levels of spatial learning and memory than the molarless group. There were no significant differences in memory retrieval during the probe phase between the denture-wearing molarless and the control group. The molarless group showed significantly worse spatial learning and memory and had fewer neurons in the hippocampus than the control group. Conclusions: Our results suggest that the loss of occlusal support decreases the number of pyramidal cells in the hippocampus and impairs memory decoding and retrieval. However, this effect is suppressed by the reconstruction of occlusal support.

KW - Hippocampal neurons

KW - Loss of molar teeth

KW - Memory retrieval

KW - Occlusal support

KW - Rat

UR - http://www.scopus.com/inward/record.url?scp=85060464326&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85060464326&partnerID=8YFLogxK

U2 - 10.1016/j.jpor.2018.12.009

DO - 10.1016/j.jpor.2018.12.009

M3 - Article

C2 - 30686619

AN - SCOPUS:85060464326

JO - Journal of Prosthodontic Research

JF - Journal of Prosthodontic Research

SN - 1883-1958

ER -